I've been fortunate to work with a number of great mentors and colleagues during my time as an archaeologist for the Forest Service, and as a graduate student at Michigan Tech. A benefit of being in academia is the opportunity to listen to other researchers present their own work.  A recently retired history professor from MTU, Fred Quivik,  who I've worked with during my MS and PhD research, presented a paper in November of 2015 on mill tailings in Montana. During this talk Fred highlighted an important fact, one that I had overlooked as I've studied mining - simply that "Ore is an economic term".

Whoa! 

​That cogent sentence changed the way I understood the mining industry, and changed the way I looked at concepts like value and waste.  In mining, what is value today, might be waste tomorrow - and vice-versa - judgments based on economics, technological development, and culture. In mining heritage we can see similar parallels, as what we value collectively can change with time, with politics, and with economics. Both of these fields,  mining and mining heritage, ascribe value judgements to things, such as minerals, machines, and memory, based on shifting, and abstract cultural constructs.

Since Fred's talk and as my research has progressed, I've found myself writing and reflecting about concepts like value and waste - especially how it  relates to mining, heritage, and the environment - examining closely the often  blurry line that we draw to divide the two.

I will return to this idea later - but for now we will explore the history of the Harrison Concentrator,  the third beneficiation plant constructed in the Mesabi Range, which the Butler Brothers Mining Co. used to convert a material previously considered waste into an abundant source of value in the form of iron ore concentrates.

Unlike other iron ranges, from its inception in the early 1890s, the Mesabi Range has been dominated by open-pit mines. When a mining company wants to develop an open-pit mine, one of the first steps is to expose the iron ore deposit itself, effectively isolating value- or the ore- from the surrounding waste.
​
Exposing a shallow ore deposit involved peeling away the organic layers (called overburden) from the  mineral deposit which it was encasing. The Butler Bros. of St. Paul were a prominent mine-stripping company active in the Mesabi Range during early part of the 1900s. By 1914, Butler Bros. expanded their activity from mine developing toward actual mining, and opened a swath of land just south of Nashwauk, and north of historic Cooley, MN, which contained a large quantity of low-grade washable ore. ​

 As you will notice in the title of this post, the Harrison concentrator was also known as the Harrison-Quinn concentrator, due to the plant processing the ore from both mines. The dual naming of the plant made tracking down information on the plant a little tricky, since it might be labeled as either the Harrison concentrator, the Quinn concentrator, the Harrison-Quinn concentrator, the Quinn-Harrison concentrator, or the Cooley plant - I even thought they might be two separate plants to begin with - but I digress.

The Harrison concentrator processed ores from nine separate mines, all within a relatively close 2-mile radius to the plant itself, including: the Harrison (1914-1967); the Quinn (1914-1965); the Crosby/Hoadley (1916-1950); the Mace No. 2 (1920-1959); the North Harrison (1915-1956); Harrison Annex (1923-1940); the North Harrison Annex (1925-1940); and the Halobe (1930-1959) - collectively called The Harrison Group.
​Note that the dates given for these mines include sporadic periods of inactivity.  

The Harrison concentrator operated from 1914 to the mid-1960s. Towards the end of its operating life, shipments from the Harrison Group were composed primarily of stockpile concentrates, rather than newly mined ores.

During its operation the Harrison produced over 27-million tons of iron ore concentrates. To process that much ore, took even more water, nearly 25-billion gallons - used to help remove the lighter silica waste, and concentrate the valuable iron ore.

During the winter of 1917, Butler Bros. began developing plans to expand the concentrator to a full-one unit, a size comparable to the nearby Hawkins concentrator (Iron Trade Review 01-04-1917). The one-unit size would help the concentrator process more ore per year, up to the 8,000 tons per day goal seen in the citation above. 

From the time of its construction, the Harrison concentrator underwent continual modifications to its flowsheet, as Butler Bros. continued to implement new technologies in an attempt to capture more value. In 1929,  a nearby beneficiation plant, the Stanley, was dismantled. The Stanley plant was equipped with the first system of jigs in the Mesabi Range, which upon dismantling were installed in the Harrison concentrator. By 1939, a process of heavy-medium separation was introduced to the concentrator, which used cone-separators to help further concentrate the iron ore. 

In 1948, the holdings of the Butler Bros., including the Harrison property, were sold to the larger M.A. Hanna Co, who operated it for the next twenty years. By the late 1950s, the low-grade deposit of the Harrison Group was becoming exhausted and the mine operated sporadically for the next decade - often shipping concentrates from stockpiles, rather than new ore.

The Harrison concentrator was likely scraped by the Hanna Co. during the late 1960s, as the ore body from the once profitable Harrison Group became exhausted. 

Ore is not simply something that is dug out of the earth. This advertisement, for the still functioning Naylor Pipe Co., elucidates that the materiality of what is, and what is not ore, can change. That for a mineral to be considered ore, it needs to have some sort of value on the market. If there is not market value then it is not an ore. In this advertisement, the tailings that the dredge is reclaiming were once deemed waste, separated from value and laundered into a pond. But as new technologies developed and economic systems changed, so too did our perception of these tailings as waste, they now could exist as something entirely different. Suddenly they had value, that could be reclaimed and converted back into an ore.  

What remains of the Harrison concentrator is its footprint of transportation and waste. As I continue my research on low-grade iron ore mining in the Mesabi Range, waste continues to dominate the story.  

What role can historical mining waste play in shaping contemporary environmental policy and mine management plans?

Can valuing waste - in a heritage context - engage the public with not only how the waste got there, but what the waste consists of, how to best negotiate it, and why understanding its history matters?  

In terms of industrial heritage I believe that waste needs to be at the forefront of our current discussion, which is too often focused solely on tourism and preservation.

What do you think?

​"Almost everything is a dull rusty red. This is the color of the railroad ties, of the soil, of the stockpiles, and even the buildings of the mines.
​The landscape has a blasted and forlorn look, even though most of the mines are operating, somehow (it) always seems lifeless and desolate."
​ - George F. Brighten, 1941

​At a site about 100 miles south of the Mesabi Iron Range on the Cuyuna Iron Range an unusual ore refinement process was conducted during the mid-20th century. It was unusual because it was the only example of its type in the Great Lakes region and also for its scale, as the largest of its kind in the United States while it was in operation. The Portsmouth Sintering Plant operated for 42 years, even for 8 years after its local mine closed, because it processed the unmarketable portion of fine-grained iron ores found across the Cuyuna Range into a marketable product called sinter.

Sintering mixes small iron ore particles with coal fines and then heats the mixture to the point the iron fuses together into larger clumps. Portsmouth Sinter became what one writer called a “cracker jack man-made ore” that was “a well known trade name” throughout the iron industry of the time[1].

​Reports from this site show its daily production grew over time from around 800 tons in 1925 to nearly 1700 tons by 1950 as the machinery and management of resources were improved. In 1944, the output of this sintering plant was estimated to contribute 204,000 tons or 34% of the 589,000 tons of annual output from its mine location.

This process of excavating, transporting, and heating fine grained ores created a significant amount of dust which had a noticeable impact across the region. George F. Brightman, an economic geographer, gave a fascinating description of the height of mining in the Cuyuna Rage during World War II. Shortly after describing the massive tailings piles connected by radiating “ribs” of railroad lines to benefaction plants, he then describes the incredible amount of dust present everywhere he went.

He said:“Almost everything is a dull rusty red. This is the color of the railroad ties, of the soil, of the stockpiles, and even the buildings of the mines. The landscape has a blasted and forlorn look, even though most of the mines are operating, somehow always seems lifeless and desolate”[2].

Residents that lived through this era in the mid-20th century told me they could not leave clothes out to dry on certain days because it would become covered in red dust if the wind blew from the wrong direction.
Other references to the air quality near this plant were not recorded in documents I have been able to find, but must have certainly been an issue in the daily life of mine workers and their families. A current issue involving the fine grained materials from former mines is protecting water quality.
​This fine grained iron rich material erodes easily, causing significant shoreline loss and water contamination issues around former mine pit lakes. Efforts at planting and managing trees along these shores is an ongoing challenge [3].

“Portsmouth Sintering Plant is operating at a high rate and is steadily sending out loaded railroad cars to the ore docks. The plant is a lone operation of its kind and favors sintering ore at the source instead of sintering at the point of consumption -a controversy held in abeyance for years. Portsmouth Sinter is a well known trade name noted for its excellent structure, high iron content, and low moisture. Its crunchy appearance might lead to its being called the ‘cracker jack man-made ore’ of the Cuyuna Range.” 
Skillings' Mining Review, 1951

The ruins of this sintering plant remain on private property, but there is a public walking trail crossing County Route 30 north of Crosby that goes within eyesight of the concrete remains. The ruins are listed on the National Register of Historic Places, incorrectly, as the ‘Ironton Sintering Plant’[4].

​The site is within the municipal bounds of the City of Crosby and it was only called the Evergreen or Portsmouth Sintering Plant while it was in operation. The legacy of this site is that it was an important facilitator of regional iron production, even after its local mine closed. It was also an outlier for its size and approach to refining iron ore in the Great Lakes Mining District. The environmental legacy appears to be tied to the fragile shorelines and bodies of water around the remnants of the open pit mines the sintering plant helped to sustain in the 20th century.

Upper Panasa Lake is small, murky, and unspectacular. Viewed from above, Upper Panasa Lake stands out from the dozen or so other lakes that surround Calumet, MN not because of its size or shape, but due to its pale green color - reminiscent more so of pea soup than as the aquatic home for bullhead, northern pike, and pan fish. 

​Although its appearance may be drab, Upper Panasa's industrial past is quite vibrant, and it begins in part with the Hill-Trumbull washing plant and the 24-billion gallons of water it sucked from Upper Panasa Lake over half a century to process silica-laden low grade iron ore.

Located just south of Calumet, MN and within the western Mesabi Range, Upper Panasa Lake was bordered historically by two low-grade iron ore washing plants, the Hill-Trumbull plant on its northwest bank, and the Hill-Annex plant on its eastern (-the latter of which stands as the sole washing plant within the Mesabi Range that has been recognized as a heritage site-). ​

Unlike some of the custom mills this blog has examined in the past, the ore that was treated at the Hill-Trumbull washing plant came solely from the Hill-Trumbull mine, a long ore body that runs for nearly a mile. The Hill-Trumbull mine,  which was first opened in 1909 by the Oliver Iron Mining Co., and the Mesaba Cliffs Iron Co, is actually two individual mines that were eventually consolidated, with the Trumbull mine lying within the western half of Section 17, and the Hill mine within the eastern half.  The Hill mine's likely namesake was the noted "Empire Builder" of the Mesabi, the prominent railroad tycoon and land baron, James J. Hill.

As the open pit mining operations at both of these mines expanded along the ore body their excavations eventually met, crating a vast cavity, seen in the aerial image above as the long lake just north of Calumet.

For nearly the first decade of its operation the Hill-Trumbull mine employed selective mining - extracting only the pockets of high-grade direct shipping ore, found primarily at the Hill mine, while avoiding the vast tracts of silicious ore that made up the majority of Section 17. But, in 1919 the Mesaba Cliffs Iron Co. (the mine owner, nee Cleveland Cliffs)  purchased a tract of land south of the mine and began drawing plans for the construction of a standard washing plant, tailored specifically for the siliceous ores of the Hill-Trumbull mine. 

Constructed in 1920, the Hill-Trumbull Washing plant joined the Hill-Annex washing plant as the two primary ore processing plants in the Calumet region.  The location of the plants near Upper Panasa Lake was not happenstance, as we've seen with all ore processing plants, an abundant supply of water was as nearly as important to a mining company as was a profitable ore body - and Upper Panasa Lake just happened to fit that bill.  Water for the Hill-Trumbull washing plant was pumped from Upper Panasa, by means of a pumping plant (situated on the southeast side of the levee line portrayed on the topographic map above).  The pumping plant consisted of two pumps, a primary and an auxiliary, and delivered roughly 2,000 gallons per minute to the washing plant by means of a "20-in. spiral-riveted pipe line."
​H.C. Bolthouse, "Beneficiation of Hill-Trumbull Mine Ores", in The Mining Congress Journal, Oct. 1929, pp. 756).

"It is worthy of note that, from the time the first piece of steel was erected until the first ore was put through the plant, a period of just 90 days was consumed."
H.C. Bolthouse, "Beneficiation of Hill-Trumbull Mine Ores", in The Mining Congress Journal, Oct. 1929, pp. 753).

The Hill-Trumbull plant was a standard one-unit plant, meaning that is consisted of specific technological components, including a primary crushing house, an ore conveyor, and, within the washing building itself, a trommel, log washers, and concentrating tables.  The ore that arrived at the Hill-Trumbull washing plant came via train, and the plant was originally designed to handle "80 cars per shift ", a number that would grow along with the plant as it was retrofitted with improved technologies over the next forty years. 
(EMJ, Vol. 110, No. 10, 4 Sept. 1920, pp. 498)

Within standard washing plants, water was introduced at almost every stage in the classifying and concentrating process.  Briefly, the process at the Hill-Trumbull washing plant was as follows (though a more thorough description of individual technologies is provided in the write-up on the Coons-Pacific Iron Ore Concentrator):

-After the ore was delivered to the plant, it was first classified and sized at the crushing plant, which consisted of the ore being dumped onto a grizzly, with the oversized material sent to a jaw crusher to further reduce the size of these larger chunks of ore, while the fine material fell through the slats of the grizzly onto a conveyor belt.  Once the oversized ore was reduced to a size copacetic for treatment, a conveyor sent the ore up an elevated and covered conveyor to the washing plant.  
-At the washing plant, the ore was fed into a revolving trommel, where jets of water were introduced to the machine in order to help break up and remove any loose sand and debris from the ore as it was passed against the trommel's internal screen.  
-Next, the material from the trommel (both the classified ore and the water), along with additional fresh water are processed within a log washer, which, in the case of the Hill-Trumbull, were 25-foot long machines set at a declined tilt, that contained paddle-lined shafts rotating at a moderate speed of 15 rpm.  The log washers were arranged at a tilt so that the lighter fine material and tailings would travel downward and flush out of the washer's bottom opening, while the heavier and coarse material would be forced upwards thanks to rotation of the paddles.  
-The coarse material would be discharged through the elevated end and sent to concentrate bins. The overflow and the material that was flushed out of the washer's bottom were next introduced into a series of turbos, a device similar to the log washers, except the shaft rotated at a slower speed, aimed at processing much more delicate material.  The fines from the turbos laundered into the nearby tailings basin. 
​​H.C. Bolthouse, "Beneficiation of Hill-Trumbull Mine Ores", in The Mining Congress Journal, Oct. 1929, pp. 755-756).
​
The amount of water needed to wash the silica-laden ores in the Mesabi Range varied by ore body and by technology, but on average 900 gallons of water were required to process one ton of washable ore.  In the case of the Hill-Trumbull, which shipped a total of 27,128,463 tons of ore during its operation, this equates to nearly 24.5 billion gallons of water, a hefty sum considering the meager size of Panasa.  

Why the Hill-Trumbull and other washing plants in the region decided to construct tailings basins rather than simply dump their waste in nearby waterbodies or swampland is unknown (although I do hope to discover this during my research). It is possible that legislation was already in place that forbid the direct dumping of mine waste into water bodies. It is also possible that Cleveland Cliffs planned on reclaiming some value from these tailings at a later date through an improved technology.  Nevertheless, the roughly 3,500-ft x 1,000-ft. basin was constructed around 1920 on a "tract of low swamp land...lying between the washing plant on the west end and Little Penacie Lake on the east side. This area is not a naturally inclosed basin, therefore it has been necessary to cast a dike along the north, east, south and part of the west sides in order to prevent the tailings from flowing into the lake." (note the spelling of Panasa Lake here as well as Panaca on the topographic map above).
​​H.C. Bolthouse, "Beneficiation of Hill-Trumbull Mine Ores", in The Mining Congress Journal, Oct. 1929, pp. 756).

 In the Mesabi Range, tailings basins contained both mineral waste, such as silica, as well as large amounts of wash water that was used during the beneficiation process. Mixed together, these ingredients create a brown stew with a constitution similar to the stuff found at the bottom of a pot of cowboy coffee - silty and murky, but still liquid.

Since the tailings produced in the washing plants of the Mesabi had a liquid consistency, the tailings basins constructed to contain them needed strong walls - and if the mining company was attempting to maximize the internal volume of the basin, a dewatering system would allow more room for the solids by removing the abundance of liquid. At the Hill-Trumbull tailings basin, Cleveland Cliffs installed such a dewatering system. The Hill-Trumbull system used adjustable overflow pipes to remove the water that sat atop the settled tailings.  These pipes could be raised or lowered depending on the state of the tailings, with a calm basin allowing for the pipes to depress further into the basin, while a turbid basin would suggest that the pipes should be raised until the tailings settled. The water removed from the tailings basin was simply pumped directly back to Upper Panasa Lake, as no filtration or treatment was deemed necessary.   

Although erecting the Hill-Trumbull washing plant was completed in a matter of mere months, the construction and maintenance of its tailings basin and dike required ongoing construction and maintenance in order for it to effectively contain the continual flow of tailings that emanated from its launders. The walls of the tailings basin at the Hill-Trumbull were constructed from the tailings themselves - which over the course of its lifetime amounted to over 40-million tons.  Cleveland Cliffs employed a gasoline powered dragline excavator to dig up the tailings at the bottom of the basin and then continually restacking them as it built up and fortified the basin's walls.           
​​H.C. Bolthouse, "Beneficiation of Hill-Trumbull Mine Ores", in The Mining Congress Journal, Oct. 1929, pp. 756). 

During the midst of the Great Depression, the Hill-Trumbull mine, like many other mines, was left idle.  There is little published accounts of the washing plant from 1929 until after WW2, and these accounts tend to be overly technical in nature, providing technical descriptions of new machines installed at the plant and the results of their operation. 

In 1948, Cleveland Cliffs added a spiral concentration section to the Hill-Trumbull plant in hopes that it would help capture some of the fines lost in the washing process.  The spiral section at the Hill-Trumbull was massive, and consisted of 84 spiral units which were able to treat roughly 120 tons of siliceous ore per hour.
Whitman E. Brown, "Humphreys Spiral Concentration on Mesabi Range Ores", in AIME Mining Transactions, June 1949, Vol. 184, pp. 187.

Two years later, the Hill-Trumbull plant expanded again, with Cleveland Cliffs installing a Hardinge Heavy Media Separator to the HMS section (this section was installed sometime between 1929-1949).
"Cleveland Cliffs Iron Company Uses Separator on Trumbull Ore", Mining World, August 1950, pp. 37. 

A final addition was made in 1953, with Cleveland Cliffs erecting a cyclone plant, a relatively novel technology within the Mesabi at that time.  By 1955 the Hill-Trumbull washing plant was treating 85 long tons of ore per hour,  a significant decrease from the 1948 operation.
R.A. Derby, "Cyclone Plant Improvements Up Recovery of Mesabi Iron Ore", in Mining World, March 1955.  

By 1973, the majority of the Hill-Trumbull washing plant and its ancillary structures were disassembled and scrapped, as Cleveland Cliffs sought to reclaim whatever value was left within the obsolete steel structure of the plant, crushing house, and conveyor. The historical record never mentions the construction of a secondary tailings pile located to the west of the washing plant, but aerial imagery and LIDAR data tell a different story.

A  strength of industrial archaeology is that it treats industrial landscapes as artifacts - that is these landscapes coupled with the historical record can help unravel new narratives about our past that we might not have uncovered otherwise.  And unlike historical records, landscapes don't lie.

Although it was constructed out of organic material, the tailings basin of the Hill-Trumbull washing plant is the last physical vestige of this ghost plant and it's half-century of operation. While Cleveland Cliffs boasted about the speed in which it erected the Hill-Trumbull washing plant, the modernizing of the plant with cyclones and spiral units, and the savvy nature of their metallurgists willing to tackle the ongoing challenge of beneficiation, it remains somewhat ironic that these piles of siliceous waste serve as the Hill-Trumbull's legacy.  

At certain scales, Upper Panasa Lake looks more like the creation of an unorthodox alfalfa farmer than a natural waterbody.  This is because Upper Panasa Lake is categorized as eutrophic  - meaning that it contains an abundance of nutrients, such as nitrates and phosphates - ingredients commonly found in fertilizers employed to accelerate the growth of plants. When these nutrients are introduced into lakes at an industrial scale, the response is similar to a farmer's field that has been treated with fertilizer. Plant matter begins to flourish, and competition for sun light soon favors those species that tend to grow and expand the fastest. In the case of Upper Panasa Lake, that species is algae. The rapid growth of algae in lakes, called blooms, creates a wealth of ecological problems, as the shortlived plants not only feast on the nitrates and phosphates, but as they die and decay they also consume vast amounts of oxygen, which slowly suffocates other aquatic life.  The eutrophic state of Upper Panasa Lake is owed primarily to the sewage treatment plant that serves as one of its inlets, but I'd be willing to gamble that the industrial legacy of the Hill-Trumbull ghost plant, its tailings basins, and water plant continue to silently add to its distress.     ​

Historic mining landscapes can be read as palimpsests, featuring the the ongoing conversation between an evolving technological system and its changing environment.  Sometimes these conversations are easy to follow, but more often than not, they tend to resemble the creative genius of Sokal - convoluted, cacophonous, and confusing. When reading mining landscapes it is often difficult to remember that many of the mining features that may seem ubiquitous today were not always there.  Instead, these features are products of an evolving technological system - artifacts of the conversation between technology and nature.  In the historic Mesabi iron range, tailings ponds and tailings basins are mining features evident throughout the range's 100 mile stretch, running from Grand Rapids to Babbitt, but less than a century ago, these mining features were absent, as the concentrating plants that created them were still only nascent features on the landscape.       ​

This brings us to a question I continue to dwell on:  What impact did the sudden visibility of tailings in the Mesabi Range have on public perceptions regarding iron mining, ore processing, and the environment?   

Part of the answer to this question is found near Nashwauk, MN and the O'Brien Lake ecosystem, where a handful of Hibbing "publicans" saw the shoreline of their summer retreats turn red during the summer of 1912.

​The Hawkins washing plant was the second low-grade concentrator built on the Mesabi Range, erected 2 years after Oliver Iron Mining Company’s concentrator at Trout Lake went into service.  Built by the International Harvester Co., and operated by the Wisconsin Steel Co., the Hawkins washing plant was designed to treat an average of 5,000 tons of washable ore per day.  During its first year of operation the Hawkins concentrator was receiving between 50- 60 cars of ore per day from its namesake mine, resulting in the concentration of around 500,000 tons of ore for the 1912 season.
(Mining & Engineering World, 2 November 1912, pp. 819).

 Although it wasn't the first constructed (see the Trout Lake Concentrator),  didn't have the largest capacity, nor was it the longest running beneficiation plant in the Mesabi, the Hawkins washing plant was the first processing plant to create public outcry over its production and disposal of tailings in the Western Mesabi.        ​

One of the joys of research are those serendipitous moments when you locate a gem of information you didn't know you were even looking for.  Case in point with the Hawkins concentrator.  I began skimming through old trade journals from 1910-1914, looking for information regarding the plant's technical make-up, but instead stumbled upon a handful of entries regarding lawsuits and public reaction to the Hawkins' production and disposal of tailings.

Entry 1: During this time period (1913) the construction of tailings basins was unheard of in the Mesabi Range.  Dumping of tailings in water bodies was common place, and any negative effects felt by the public were simply written off as meager impacts from living with the many benefits of the industrial machine: ​

Entry 2:  Here, you can ascertain how the mining industry, and civil servants felt about complaints regarding the mining industry.  Environmental concerns were not taken seriously, and questions of environmental justice were viewed as fallacious.  ​

The only real change in the concentrating process as compared to the Trout Lake concentrator, which the Hawkins was modeled after, was the commission of tables for fines. This meant that the Hawkins plant's  required less water for washing than the Trout Lake concentrator, running on an initial consumption rate of around 1200 gallons of water per minute.   

Entry 3: The company response resulted in the the safe keeping of Swan Lake, but also the creation of a stagnant pond at O'Brien.  

The migration of tailings that moved from the launders of the Hawkins' concentrator, through O'Brien Lake, into O'Brien Creek, and eventually settling on the banks of Swan Lake resulted in one of the first instances of the public attempting to use legal avenues to protect their environment.  This action forced the International Harvester Co. to construct the first tailings remediation structure in the Mesabi Range.  This tailings dike that was constructed, was put in place to alter the route of the migrating mine waste, a strategy the company pursued to likely lessen the chance of future lawsuits and public ill will, and to thwart future legal intervention into the mining company's day-to-day activities.     However, this landscape alteration had a lasting affect on the O'Brien ecosystem, as it plugged up one of O'Brien Lake's main arteries.

During the 1952 season the original Hawkins concentrator was shut down and a new facility was opened adjacent to the Hawkins pit.  I've yet to discover if old plant was simply moved to the new location, or if an entirely new facility was constructed.  It does look like that in 1953, additions were made to new plant, including an additional sink-and-float Heavy Media section, as well as a 2-unit cyclone plant. 
​(EMJ, Vol. 154, No. 7, July 1953, pp. 202).

 -Updated-
Entry #4:  During the late 1950s the impending exhaustion of the Hawkins Mine became apparent to Cleveland Cliffs, and attention was placed on the nearly 8-million tons of tailings residing within O'Brien Lake.  As the company began to draw up plans to reclaim and retreat these tailings, questions of ownership were challenged by the State in court:

"The district court, in an action brought against the International Harvester Co., Cleveland Cliffs Iron Co., and others, by the state of Minnesota, held that iron ore tailings deposited in O'Brien Lake near Nashwauk did not belong to the state.  The tailings, amounting to nearly 8-million tons, came from the Hawkins mine, formerly operated by the International Harvester Co., between 1923 and 1951. The court held, however, that the state owns the land under the lake and that a trespass was committed when the tailings were deposited there.  The court ruled that the mining company had not abandoned the tailings, but had stored them in the lake until a process could be discovered for its economical treatment.  The Hawkins Mine, through 1951, had produced 18,719,321 tons."
(EMJ, Vol. 161, No. 4, April 1960, pp. 186-187).

Cleveland Cliffs closed the Hawkins mine in 1961, and during the winter of 1962-1963, the Hawkins washing plant and associated buildings were disassembled and removed from the landscape.  During its years of operation (at O'Brien Lake and at the mine), the Hawkins treated over 25 million tons of sandy ore. 
(L.F. Heising and R.C. Briggs, The Mineral Industry of Minnesota, pp. 591)

Like all of the other ghost plants, the Hawkins concentrator at Nashwauk is visibly absent from the landscape.  Its social and economic legacies have been forgotten - hidden in dusty trade journals and consolidated into a small collection of bankrolls. What does remain of the Hawkins ghost plant is the ecosystem modifications that it created at O'Brien Lake.
 
The processing of low-grade ores created new challenges for iron mining companies and mining communities.  These challenges were rooted in how to acquire the billions of gallons of water required for washing and laundering purposes, as well as where to deposit the millions of tons of tailings they produced in the concentrating process.  In terms of tailings, the operators at the Hawkins concentrator had a number of options, they could construct a basin for the tailings or excavate a pit to dump them in, but these were costly endeavors - the most inexpensive option was to simply dump the tailings into O'Brien Lake - which the Hawkins plant did.

The historic mining community of Leetonia, MN is located in the eastern section of the Mesabi Iron Range, roughly 3 miles west of Hibbing, MN and 1 mile south of the massive Hull-Rust-Mahoning Pit.  Shaped like an upside down "L", the community of  Leetonia is laid out in an orderly grid with five streets running north-south, and five streets running east-west.   The streets running north-south follow a numerical naming convention, while the names of the east-west streets bear the names of former mines, such as Morton, Dale, and Kerr - unintentional memorials to a handful of ghost mines consumed by the nation's growing demand for taconite.   Both the Dale and the Kerr produced low-grade washable ore, material that was treated for a handful of years at one of the more notable mobile beneficiation plants in the Mesabi, the North Uno washing plant.

Incorporated in 1946, the Pacific Isle Mining Co. was one of a handful of mid-sized mining companies that worked the incongruous tracts of low-grade ores in the Mesabi Range, which spread from Virginia,MN to just west of Hibbing.  By 1948, Pacific Isle was operating four open pit mines in the Eastern Mesabi along with conducting reclamation efforts at a handful of the lean ore dumps that were found scattered next to many of the exhausted direct shipping ore mines.  All of this low-grade ore needed to be beneficiated, and as we saw in the last post on the Coons-Pacific Concentrator, the Pacific Isle Mining Co. decided that the most economical way to treat this ore was through custom milling - and the North Uno washing plant acted as a custom mill, treating a variety of low-grade ores within the eastern Mesabi Range. 

 A custom mill is a processing facility that treats diverse ores, meaning that its flow sheet has built in flexibility, rather than those mills that were tailored to only process ore from an individual  mine.  

Custom Milling allowed smaller mines and mining companies, such as Pacific Isle, the ability to process ore at a single facility, rather than expending additional resources in constructing and operating individual beneficiation plants.    The North Uno also featured a savvy technological innovation - it was mobile - designed with the flexibility to move to a new orebody when an older one became exhausted.     

​The North Uno plant was a pre-fabricated "Wemco Mobil-Mill" designed by the Western Machinery Co. of San Francisco, CA.  Erected first in Michigan, then disassembled and freighted to Leetonia, the North Uno washing plant started processing low-grade ores at the tail end of the 1948 mining season.  Originally designed with a capacity of up to 35 tons per hour, by the end of its first season, the North Uno was upgraded to a capacity of 100 tons an hour by doubling the washing and magnetic sections.
("Pacific Isle's North Uno Mill Upgrades Varied Iron Ores", in Mining World, June 1950, pp. 12)  

During its operation the North Uno Plant treated ores from a number of mines, including the North and South Uno (both N.P. and G.N.), the Chataco, the Cyprus and Cyprus-Rust, Dale, Kerr, the Lamberton and Lamberton Annex,  the Midget, Shada, and the Smith.   The ores from these mines were of variable constitutions, meaning that each ore required a slightly differently treatment from the next.

Although the North Uno was a relatively small washing plant, it had a mighty thirst.  During its first year of operation the plant consumed upwards of 2,500 gallons of water a minute, due in part to the ore of the North Uno Mine having a paint-rock consistency.  
(E.S. Tillinghast, Mining World, July 1948, pp. 28)  
Most low-grade washing plants required around 900 gallons of water per minute to process ore, which helped remove the high quantity of silica from the sandy washable iron ore.

​Paint-rock ores were treated much like taconite for the first 40 years of open pit mining in the Mesabi Range, seen as having such small value that they were considered to be waste more so than they were thought of as orebodies.   

Once in the plant, the ore was crushed and screened much like the process employed at the Coons-Pacific, and as the classified material made its way further through the North Uno's flow sheet, it was subjected to spiral concentrating and a heavy-media section.  Roughly half of the material that entered the North Uno plant was eventually treated by the heavy-media section, which employed Hardinge Separators - machines that resembled ball mills that helped concentrate the slurry of iron fines away from the gangue material.   
("Pacific Isle's North Uno Mill Upgrades Varied Iron Ores", in Mining World, June, 1950,  pp.15)

The material that passed through the HMS was further treated by magnetic separation, a spiral section and a hydroseparator - with waste material accumulating in three distinct areas.  The large scalped barren chucks of gangue removed at the receiving bin were hauled by trucks (see image above) to waste rock piles.  Coarse tailings were sent to a coarse tailings pile, while fine tailings were pumped and deposited into a tailings pond.
​("Pacific Isle's North Uno Mill Upgrades Varied Iron Ores", in Mining World, June, 1950,  pp.13-14).

By 1950, the North Uno washing plant had doubled its processing capacity and expanded its technological infrastructure, adding a "circuit of Humphrey's spirals for the treatment of fines".
(​Mining World, 1950, Mine Development and Directory, pp. 56C).

The expansion of the North Uno washing plant represents the industrial optimism of the Pacific Isle Mining Co., symbolic of many mining companies in the Mesabi who continued to invest,  expand, and refine their beneficiation plants in an attempt to elevate the quantity of iron in their concentrates.

The 1950s saw the eastern Mesabi transform into a landscape dominated by taconite mining, and the activities of the North Uno washing plant and Pacific Isle began to garner less attention in the press than the sprawling taconite mines.

​Pacific Isle seems to have retained controlling interest in the majority of the mines listed above up to 1957, when mining production appears to stop at all of the mines with the exception of the North Uno.  The North Uno mine, and likely the North Uno washing plant were transferred to the M.A. Hanna Mining Co. soon after, and Pacific Isle soon became a producer of the past.  

In 1963 the M.A. Hanna Mining Co. deemed the ore body exhausted and closed the mine - leaving the North Uno washing plant as another redundant technology on the landscape.  My assumption is that the washing plant was likely scrapped soon after 1963 - though I've yet to uncover what happened to any of the physical technologies within the ghost plants of the Lake Superior Iron District.    

This is a video I shot of the Hull-Rust open pit mine at Hibbing, MN.  The expansion of this mine, and the increasing role of taconite led to the eventual closure and abandonment of the North Uno washing plant. 

Unlike the other ghost plants covered in this blog, the North Uno's industrial legacy is embedded with ephemerality - reflected in the plant's mobile character along with its lack of a superstructure to house the washing plant's functioning technologies.  The plant also operated for a relatively short time span - less than 15 years - never truly reaching industrial maturity, nor producing the visible environmental legacies we've become accustom to seeing in many of the other ghost plants, such as the Hunner or Trout Lake Concentrator.  
By 1961, the massive Mahoning open pit mine was already encroaching on the North Uno, digging away at the plant's rapidly shrinking foothold atop a small swath of taconite.  
​Today, nothing remains of the North Uno plant.  As you can see in the video and image above, the consolidation of the Hull, Rust, and Mahoning mines have devoured an industrial landscape - reclaiming the landscapes of the Leetonia, Kerr, Dale, Cyprus and Midget mines and sentencing the North Uno washing plant to death by redundancy.   But, the Hull-Rust-Mahoning mine has produced an entirely new mining landscape, one that features massive industrial benches and taconite terraces, emblematic of the physical, social and environmental transitions in the industrial heritage.         

Located at the southwestern corner of the intersection of Grant Ave. and Monroe St. in Eveleth, MN, stands the world's largest free-standing hockey stick (and puck) - over 100 ft. in length and weighing in at 5 tons (the largest hockey stick is actually in Canada and is nearly twice as long as the monument in Eveleth).  Dubbed by locals as the "Stick", the landmark was first dedicated by the city of Eveleth in 1995, and after seven years of harsh northern Minnesota winters the "Stick's" aspen body began to deteriorate, leading to the erection of a new "Big Stick" (measurements above) in 2002.   
The "Big Stick" and the associated US Hockey Hall of Fame serve as tourist attractions for the community of Eveleth, designated as "The Capital of American Hockey" - but  Eveleth's contemporary hockey heritage owes much to its industrial past and the large open pit mines and processing plants that fueled the city's cultural and environmental landscape for nearly a century.  
​ 
Located in the far eastern extent of the Mesabi Range - a region known more for its rich supply of direct shipping ore and taconite deposits than for low-grade washable ore - the community of Eveleth was also home to the Mesabi's first custom beneficiation plant - The Coons-Pacific Iron  Ore Concentrator - a product of savvy engineering and corporate foresight.  

The Coons-Pacific washing plant was a custom beneficiation plant built in partnership by the E.W. Coons Mining Co., and The Pacific Isle Mining Co., as a facility to process ores from their mines near Eveleth, MN.  A custom mill is a processing facility that treats diverse ores, meaning that its flow sheet has built in flexibility, rather than those mills that were tailored to only process ore from an individual  mine.  Built in 1952, and with a daily capacity of 300 tons,  the Coons-Pacific Washing Plant originally treated ores from the nine mines operated by the E.W. Coons Co. and Pacific Isle located in the far eastern portion of the Mesabi Range.  

Since it generally wasn't economically practical for smaller mines to design and construct their own beneficiation plants, custom mills were developed in the mining industry to function as specialized facilities- acting as middle men between individual mines and secondary processing facilities such as blast furnaces and smelters.  ​

​The Coons-Pacific was designed with five distinct sections for treating low-grade ore: a scalping (removal of dirt, foreign material and general crud by means of vibration) and crushing section; a washing section; a Heavy Media Separation (HMS) section; a jigging section; and a spiral section.  The design of the Coons-Pacific Concentrator drew from the success of Pacific Isle's portable North Uno concentrator (the next post in this series) which treated low grade ores in the Mesabi since the late 1940s.  However, unlike many other beneficiation plants, such as the Trout Lake Concentrator, the equipment of the Coons-Pacific was arranged without a "building to house it - made possible by the fact that the plant only operated during the shipping season."
(Skillings' Mining Review, 31 Oct. 1953, pp.4) 

The design of the Coons-Pacific flow sheet allowed so "that any time any size fraction may be rejected, sent to a concentrating section, or loaded as a concentrate.  In essence, the entire plant has the flexibility of a laboratory." 
(R.L. Burns, "Custom Milling Mesabi Iron Ores", in Mining World, July 1953, pp. 43)

​During the Coons-Pacific first years of operation, the beneficiation plant eventually treated ores from over 20 different mines, processing between 100-120 cars of ore daily.  This material was composed of varying grades, which required a variety of ore processing equipment found in the processing sections of  the Coons-Pacific Concentrator's flow sheet. (Skillings' Mining Review, 7 Nov. 1953, pp.4). 

The first step in all beneficiation plants is converting crude ore into a medium that can be effectively fed into a concentrator.  This generally involves some degree of primary crushing, as well as screening or classifying the ores into sizes - either oversized or minus-grade and undersized ores - which were amenable to concentration.  At the Coons-Pacific plant, oversized material was any ore that failed to fall through one of the many 5-inch slots that made up the surface of a vibrating screen, or grizzly.  A grizzly is simply a series of parallel bars with uniform spacing that is used to classify ore by a specific size.  

​The oversized material was crushed in a jaw crusher to an appropriate size, or was picked off and hauled to the reject pile as waste.  It is important to note that not all material sent to a beneficiation plant was actually ore.  Ore is an economic term, meaning that the material contains something of value.  If the pickers at the grizzly deem that some of the material is not ore but gangue or waste, it was rejected for treatment. 

The undersized material that passed through the 5-inch slots of the grizzly was sent next to the  washing section (see image above), which processed the ore by wet screening, a process that involved the ore traveling down a series of vibrating screen as jets of water helped disarticulate the ore from its associated loose gangue.  The washing section further classified the ore into three sizes, with the largest ore, that material greater than 1 1/2- inch sent to a secondary crusher while the remaining fines were treated on a second wet screen with a smaller classifying system than that  used by the first.
​  
​The classified material was next sent to either a concentrate bin, or it was processed further, with coarser material sent to the HMS section while the fines were sent to either the spiral section or the jigging section.
(R.L. Burns, "Custom Milling Mesabi Iron Ores", in Mining World, July 1953, pp. 43)

The purpose of ore concentration is to take a large amount of economically negligible material and convert it into a more compact and profitable commodity.  The next processing sections in the Coons-Pacific concentrator were some of the more sophisticated beneficiation methods employed in the Mesabi during the 1950s.  
Heavy Media Separation (HMS) at the Coons-Pacific Concentrator involved a trommel like device called a Wemco drum separator, that rotated on an axis and relied on gravity and centripetal force to help concentrate the ore.  Once in the HMS section, ferro-silicon was added as a separating medium to the fine washed ore which helped classify the lighter waste material as float product, and the heavier ore as sink product, which eventually found its way to the concentrate bins.   

In the washing section at the Coons-Pacific Concentrator, the finest material (that under 1/4-inch) was treated in a Wemco classifier - a long tilted machine that looks like a massive slow turning auger placed within an open box.  Inside the classifier the fines were mixed with water and as the classifier's auger rotated, the content that spewed over the edges of the box was sent to the jigging section.  

​Jigs were used to concentrate very fine washable ores.  Jigs utilized gravity much like the Wemco classifier described above to concentrate ore, but jigs were arranged vertically and relied on a slow plunging effect that would cause lighter material to overflow from the sides of the jig as waste, while heavier, valuable material concentrated towards the base of the machine.  The overflow from the jigs was hauled to the tailings pond while the concentrated ore was sent to the concentrate bins.

While HMS and jigging were both well developed concentrating techniques used in the Mesabi beneficiation plants, spiral concentration was still a somewhat novel process, not introduced to the range until 1947.
(Judson Hubbard, "Spiral Concentration", in Mining World, Sept. 1948, pp. 41-44) 
​
Like most forms of concentration, the spiral section also relied on gravity and the equipment's shape to help concentrate heavier material towards the center of the spiral as the feed traveled downward towards its base.  The Coons-Pacific Concentrator was equipped with 36 spirals, each of which had 5 turns, or levels in which the ore spun around the machine.
(R.L. Burns, "Custom Milling Mesabi Iron Ores", in Mining World, July 1953, pp. 45)

All of these concentrating methods created waste - some coarse and others fine.  In the Coons-Pacific Concentrator two distinct types of waste were produced - tailings and waste rock.  The tailings at the Coons-Pacific Concentrator were those fine materials that overflowed in the concentrating sections, as they happened to be lighter and less dense than the concentrated iron ore.  These tailings were pumped into nearby settling ponds.  The coarse waste rock was dumped adjacent to the plant, close to the crushing and scalping section, as the majority of this never ventured farther than the scalping table. 

In 1968, Pacific Isle Mining Co. suspended its mining operations and the newly formed Coons Pacific Co. assumed ownership of the Coons-Pacific Concentration plant.  By 1969, the Coons-Pacific Concentrator  was subsumed by the larger Pittsburgh Pacific Co., who apparently operated the plant until the early 1980s.    

I've been unable to locate reports of the Coons-Pacific's closure, but from analyzing aerial imagery and examining published production totals from Pittsburgh Pacific mines, I believe the Coons-Pacific shut down around 1982.  The scrapping and removal of the plant likely happened soon after, as by 1989 all that remains of the plant are the concrete pads that once supported the five concentrating sections, pockmarks of concentrating bins, and the linear routes of abandoned rail lines.  The walls that supported the massive tailings basin remain, as they do at the majority of the ghost plants in the Lake Superior Iron District- the ubiquitous vestiges of a forgotten envirotechnical system within a postindustrial landscape.    

Today, the triangular shaped tailings basin produced from the Coons-Pacific Concentrator is the most visible signs of the plant's existence - and like other ghost plants, this waste serves as the Coons-Pacific Concentrator lasting legacy on the postindustrial landscape.    ​

The waste piles produced from those industries whose business it is to extract and process mineral deposits have a tendency to outlive the mines, plants and mining engineers who created them.  
With the exception of the tailings produced by the Reserve Taconite Plant at Silver Bay, MN (which sent its tailings directly into Lake Superior), the waste piles from iron beneficiation in the Lake Superior Iron District are not ghosts - in fact they often serve as the last physical reminders of a forgotten and scrapped industry.  Although the square concrete footings of the Coons-Pacific Concentrating Plant remain visible, they are dwarfed by the triangular tailings pond and its distinct geometric walls -  appearing more like Incan geoglyphs than the rejects of beneficiation.  

The historic Canisteo mining district lies within the far western end of the Mesabi, running a length of nearly 10 miles beginning near Grand Rapids and moving northeast towards the town of Holman.  I've covered this region in two other posts - the first on the Trout Lake Concentrator, and another on the Hunner Concentrating Plant.  The Canisteo District was home to 10 beneficiation plants which operated for nearly 70 years, from 1907 to the early 1980s.  All of these facilities now exist as ghosts on the landscape, visibly absent yet environmentally persistent.  The former location of the Canisteo Washing Plant is submerged within the flooded cavity of the Canisteo Mine, where largemouth and smallmouth bass, northern pike, bluegill and cisco now swim over the roadbeds where 15-ton dump trucks used to busily transport ore from mine to mill.  

The history of many mines in the Lake Superior Iron District are both convoluted and fragmented - with mine owners often leasing mining property to mine operators who in turn might then contract out to smaller mining companies, creating a headache for contemporary researchers.  The Canisteo's history is equally fractured and confusing.  The Oliver Iron Mining Co. (OIMC) opened the Canisteo Mine in 1906, but leased the mine to the Canisteo Mining Co., who operated it until 1925 when all of the direct shipping ore within the Canisteo ore body had become exhausted, and the OIMC was left with a surplus of sandy, low-grade ore.  

"Foremost in importance is the fact that in mines on the western end of the Mesabi range the percentage of silica has become abnormally high.  This probably affects 100,000,000 tons of ore, hitherto considered merchantable as mined, or practically so.  Attention was directed pointedly to the matter when the Oliver Iron Mining Co. canceled the lease of the Canisteo mine, because the company was unable to remove the excess silica by the usual washing process."
​A.J. Hain, "New Era in Iron Ore Industry; Trade Outlook Bright", in Iron Trade, January 1, 1925, pp. 38.

That same year, 1925,  OIMC sold the mine to the Canisteo Mining Co., who left the mine idle for the next five years until it again changed ownership, this time to the Mesaba-Cliffs Mining Co., who constructed the Canisteo Washing Plant, and operated the mine until 1938, when the mine was eventually sold to the more formidable Cleveland Cliffs Mining Co.  

Constructed during the 1929-1930 season, and placed into operation in 1931, the Canisteo Washing Plant was the Mesabi's 44th beneficiation plant, and also one of the largest in the Lake Superior District, with a capacity of nearly 700,000 tons of concentrates per year.  Prior to building its washing plant, the Canisteo mine sent its washable ore to the nearby Trout Lake Concentrator at Coleraine, the flagship plant of the Oliver Iron Mining Co.   

"Could this worthless iron ore be made available for the furnaces, could the western Mesaba be subjected to the same tremendous development that had been carried on along other parts of the range, what an opportunity for effort, what a vision for the enthusiast!"
​- Dwight E. Woodbridge ("Concentrating the Lean Ores of the Mesaba Range", in The Iron Age, Jan. 6, 1910, pp. 48).

During the tail end of the 1930 season, Cleveland Cliffs pumped more than 2 billion gallons of water from the open pit Canisteo Mine - which due to a series of ownership changes - had been left idle for a period of 5 years - allowing ground water to slowly seep into the mine workings.  When the pumps in an open pit mine cease to rid the mine workings of water, a rapid landscape transition begins, turning a "good mine" into a lake, which has happened to the Canisteo more than once.

During the 1940 season, the Canisteo plant was moved from its northern location to the north edge of the Canisteo pit.  Moving the plant was undertaken by the Worden-Allen Co. (a Milwaukee-based company that specialized in structural steel) which required dismantling the large plant -- no easy task --, as the Canisteo Plant was one of the biggest concentrators in the Mesabi - and then re-erecting it (Skillings' Mining Review, Vol. 29, No. 28, pp. 1).    

Little information remains detailing the activity of the  Canisteo Washing Plant at its historical location - but, what we can discern is that it operated there for a little less than a decade and produced a visible tailings pile which was discharged to the northwest of the plant (see the LIDAR image below).

The reasons for moving the plant closer to the mine might seem obvious - the cost of transporting the ore would be much cheaper with the washing plant next to the mine - but the reasoning behind the move were a little more complex.  In addition to extracting and concentrating ore, all mines and beneficiation plants produce waste - and figuring out where to put this waste was a reoccurring theme for mining engineers and mine owners.  The new location next to the Canisteo pit had an ample amount of land available near the mine for disposing of overburden, as well as "An excellent tailings basin site was available within a half-mile of the proposed new washing plant location."
W.A. Sterling, "Improvements at the Canisteo Mine", in Mining Congress Journal, May, 1941, pp. 12-13

While the plant retained its original flow sheet after the move, the operation within the mine changed drastically -mainly in how the ore was transported from the mine to the washing plant.  Within the mine, the 15 miles of railway (this number probably takes into effect the distance of the former location of the plant) that once hauled ore from the mine to the washing plant was removed and replaced with 50 ft. wide roadbeds for dump trucks.  
Trucks made the transportation of ore from mine to the plant more economically efficient and divorced the mine from its dependence on costly steam powered equipment at the dawn of the diesel era.     ​

In addition to the use of trucks as primary movers, the Canisteo Washing Plant employed a revamped conveying system which sent the ore from the base of the bit to the top of the plant, described below:  

Once at the conveyor -  "Over 4-inch material passes to another apron where it is handpicked and discharged to the primary crusher and then deposited upon the protective layer of finer ore already on the belt, where it travels upward over three conveyor sections to the concentrator, one of the largest on the Mesabi range with a rated capacity of about 700,000 tons of iron ore concentrates per season."
​W.E. Philips, "Belt Conveyors in Metal Mining", in Mining Congress Journal, Vol. 28, June 1942,  pp.72).

The tailings from the washing plant were laundered through an 800 ft. - 16 in. pipe into a hydro pump, which sent them next into a 1700 ft. - 12 in. pipe that funneled them into the tailings basin roughly 1/2 mile west northwest from the Canisteo Washing Plant.  The tailings basin was massive (see image below) and was reinforced with an earthen dike constructed with 15 ft. walls that measured 18 ft.  width at their top.
​(W.A. Sterling, "Improvements and the Canisteo Mine", in Mining Congress, May, 1941, pp. 13)

All beneficiation plants, including the Canisteo Washing Plant, required a complex hydraulic infrastructure in order to bring water to the plant to wash the low-grade ore entering the facility, as well as  to launder the waste away from the plant to the tailings basin.  At the Canisteo plant, this was accomplished through the development of a clean water reservoir next to the mill (see aerial image above).  The reservoir had a 10,000,000 gallon capacity and was fed from the dewatering pumps within the Canisteo mine.  Since the reservoir was located below the mill, a system of gravity pumps were installed that transported the water from the reservoir to the ground floor of the washing plant.

During the 1961 season, Cleveland Cliffs began constructing an additional cyclone plant adjacent to the main washing plant, representative of the company's continued faith in the low-grade washable deposits of the Coleraine region.
(Skillings Mining Review, Vol. 50, No. 11, March 18, 1961, pp. 5)

The plant apparently continued to operate smoothly into the 1970s, and in 1974, Cleveland Cliffs' modified the flow sheet of the plant, adding cyclone, spiral and heavy media concentration units to the facility which were operated on a "17-shift per week schedule" (Skillings' Mining Review, June 1974, pp. 19.).
​
However, the benefits of this innovation were short lived - and like most other non-taconite mines in the Mesabi, the Canisteo was on its last leg.  The Canisteo Mine and the Canisteo Washing Plant were closed in 1981, with Cleveland Cliffs deeming that the mine had "reached the end of its economic life." At the time of their closure,roughly 200 workers were employed at the Canisteo operation, which extracted more than 50 million tons of sandy ores during its lifetime (Skillings' Mining Review, June 20, 1981, pp. 5.).  

The very mine that once fed ore to  the Canisteo Washing Plant now serves as the ghost plant's watery grave, an ironic resting place for one of the largest, longest running, and technologically savvy washing plants in the Western Mesabi. 

Here's a first draft of a time series map we've created exploring natural resource use within iron ore processing plants in the Lake Superior District. This video is showing the amount of water used in these plants to process low-grade ores. Taconite, which required additional water for the pelletizing process, comes into play around 1960, resulting in dramatic increases in the scale of water use.  Calculating the amount of water required was factored by averaging reported water use at these plants over time, with the more recent plants, such as the taconite ones, providing more concrete data.  

​Let me know if you have any suggestions!

Keewatin, MN is located at the far eastern extent of Itasca County,  at the juncture of Itasca and St. Louis Counties in Northern Minnesota.  The Mesabi Range is bifurcated politically, but also geologically, as the western end of the Mesabi, those ore bodies within Itasca County, tend to be heavy in silica and light in iron, and were known historically as western Mesabi washable ore.  

During the 1929-1930 mining season,  the M.A. Hanna Co. began stripping the overburden encasing its new Mesabi Chief Mine, located just west of Keewatin,  and drawing plans for the construction of a  washing plant located south of the mine itself.  

Constructed in 1929, the Mesabi Chief washing plant had an initial treatment capacity of  roughly 400 tons of low-grade ore per hour.  The initial shipments of ore processed at the plant came chiefly from the newly electrified Mesabi Chief Mine (A.J. Hain, "Iron Ore", in Iron Trade Review, January 2, 1930, pp. 35).  Not all the ore coming from the Mesabi Chief was low-grade ore, about half of the product extracted in the early years was graded as direct shipping ore, and was not treated by the washing plant.

The most pronounced features of the Mesabi Chief washing plant was the structural steel ore stacker that lifted concentrates from the plant up a conveying belt to be stockpiled outside the facility.  The ore stacker had a stacking capacity of 100,000 tons of concentrate, requiring a surface radius of 165 feet with a 40 foot reach to the top of the pile (S.A. Mahon, "Iron Ore Stacker at the Mesabi Chief Mine", in Mining & Metallurgy, August 1935, pp. 334-335).  ​​

In addition to processing ore from its namesake mine, the Mesabi Chief Washing Plant treated ore from the nearby Aromac, Bray, Carlz No. 2, Gordon, Gordon Annex, Mississippi Group, and Stein mines.  The Mesabi Chief was the flagship mine of the M.A. Hanna Company in the Keewatin area.  Active from 1929 to 1966 (the mine did have a small shipment in 1913), the Mesabi Chief mine shipped more than 10 million tons of low-grade iron ore.  In order to process all of this ore, the Mesabi Chief, and other washing plants required a great deal of water, roughly 900 gallons of water for each ton of iron ore concentrate processed.  ​

Of the 33 known beneficiation plants in Itasca County, only one, the Butler Taconite plant in Nashwauk, was developed to process and pelletize taconite.  On the other hand, in St. Louis County there are 54 known beneficiation plants, and 10 taconite pelletizing plants.  This is an important statistic to keep in mind, when comparing the contemporary landscapes of the two counties. Taconite, too, is a low grade iron ore, lower in grade than even the washable ores of the western Mesabi. Similar to the washable ores of the western Mesabi, taconite needed to be processed before it could be fed to a blast furnace, through steps such as crushing, washing and concentrating (through magnetism).  However, due to its fineness, the processed taconite needed to be amalgamated through a process called pelletization, which tumbled the fine grained concentrate in a mixture of water and clay to produce taconite pellets. These pellets, and their physical uniformity, were the product of a unique envirotechnical system - one whose ability to produce a standardized product acted as a boon to the mines of St. Louis County, but also pushed many of the mines and beneficiation plants in Itasca County into relative obscurity.  The Mesabi Chief is one of the many ghost plants in the Mesabi Range that ultimately succumbed to the political and industrial fanfare of taconite. ​

​In 1956, near the southwestern corner of the Canisteo Pit the M.A. Hanna Company opened the Hunner Mine and began formulating plans for the construction of a modern, fully automatic concentrating plant adjacent to the mine.  The Hunner mine was active for a little over a decade - shipping a total of 8,552,182 tons of beneficiated ore from 1956-1967.   The development of the Hunner Mine began during the summer of 1955.   As with most open pit mines, the first step in opening a mine was the removal of overburden, or stripping, from the surface of the mine.  The stripping process employed heavy machinery to peel away the valueless organic material that was encasing the orebody.  Looking at the map below, take note of the massive mine dump to the west of Trout Lake.  This is likely a mixture of overburden from the Hunner mine as well as other open-pit mines in the Coleraine region.  

After the surface of the mine was stripped the steam shovels, bulldozers, and draglines began cutting away at the low grade ore, extracting buckets full of the washable ore.  To properly function, concentrating plants required a uniform material, and since the low grade ore extracted from the pits was irregular and lumpy, the ore needed to undergo an initial processing before being beneficiated.  This initial step took place at the primary crushers, often located within the mines themselves.    

Primary crushing plants employed a fairly straight forward technological system, that classified the ore and then reduced it to a size amenable to concentrating.  The first step in the primary crushing plant was classification, or sizing, where ore would be dumped over a plane of evenly spaced bars, called a grizzly.  The material that fell through would next enter a secondary crusher, such as a ball mill, while the material that was to big to fall through would be picked off and sent to the crusher, which reduced the ore to a size that allowed it to travel through the grizzly.  Operating like Pac-Man with an inverted mouth, jaw crushers often functioned as the reduction technology employed within these facilities.  Ore was dumped into the top opening of the crusher - the top section of the crusher would stay open while the bottom compressed and articulated, crushing the material into a size small enough to pass through the crusher and the grizzly below.  Once the ore had been sent through the primary crusher, the grizzly, and perhaps the secondary crushers, the material was hauled to the concentrating plant to undergo beneficiation.   

The Hunner Concentrating Plant treated upwards of 800 tons of ore per hour - requiring a significant amount of fresh water to wash the ore, as well as to launder the tailings away from the plant.  In addition to the rail lines and conveyors that moved ore and concentrates from mine to mill and mill to stockpiles, the Hunner Concentrating Plant utilized a fairly sophisticated water transportation system to bring the liquid commodity to the plant.  Pumps, water lines, and a radio-control system monitored the transportation of the 11,000-12,000 gallons of fresh water a minute that was being pumped into the concentrating plant through a  3.25 mile long pipe, while at the same time, the same system was pumping an equitable amount of tailings from the plant through a 3.5 mile-long, 16 inch tailings pipe (Mining News, 1957, Vol. 19, No. 09, pp. 43).  The tailings were deposited in a pit north of the mine and north of the eventual Canisteo Pit.     

Within the Hunner Concentrating Plant the ore was treated in a three cycle system, consisting of  washing, heavy-media separation, and spiral concentrating - each cycle entailing a further step in the beneficiation of the low-grade ore.  Heavy-media separation treats the oversized ore from the washing cycle through a process similar to floatation, where the specific gravity of the ore lends to it concentrating separate from the lighter gangue material.    The spiral concentrating plant treats the fines from the washing plant through a system of vertical screw-like machines, that rotate and swirl the pulpy ore and water mixture allowing for the heavier ore to sink, while the lighter waste material spills over the top of the spiral bowl.

Maybe since it operated for merely a little over a decade, or possibly due to the expansion of the Canisteo Pit, nary signs of the Hunner Concentration Plant are evident in either the social or environmental landscape of Coleraine.   Not visible in aerial imagery from the late 1980s, it is assumed that the Hunner Concentrating Plant was scrapped sometime in the 1970s.    From the LIDAR image above, the linear transportation routes of the Hunner Mine and Concentrating Plant still remain evident, lasting reminders of the flow of materials within the Coleraine industrial landscape.  The legacies of waste from the Hunner Mine and the Hunner Concentrating Plant also remain, found in the overburden pile south of the mine and a tailings basin nearly 3.5 miles north of where the plant once stood.