Industrial Fertilizer in the USA
THE GROUND OUR FOOD EATS
PLANTS GET CARBON, HYDROGEN, AND OXYGEN from air and water, but the rest of what they need to grow comes from the ground, often from a nearly inert soil that is reconstructed and recharged with fertilizers between each planting.
As most gardeners know, the three basic elements of fertilizer required for plant growth are nitrogen, phosphorus, and potassium, often represented by their symbol on the periodic table of elements: N, P, K. In addition are other macronutrients and micronutrients like sulfur, calcium, magnesium, iron, zinc, and copper. In industrial agriculture, which provides more than 90% of the food Americans eat, these inorganic elements are mined, rather than grown—extracted using open pits and underground mines, and from fossil fuels pulled out of the earth.
Our collective appetite, therefore, extends through the plants and animals we eat, and even beyond the fields from which these staples are formed, for these fields are just a medium—an outdoor factory floor. The ultimate source of our food, you could say, are the places where the nutrients that make our food come from. In this way we are not herbivores and carnivores, but geophagists—people who eat the earth.
The Basic Elements of Fertilizer: NPK
Nitrogen is prevalent in the earth’s atmosphere, but in order for it to be absorbed into plants, it has to be fixed in the soil. This limitation on agricultural production was overcome by technology in the early 1900s with the Haber process, which uses gas to make ammonia, a highly reactive form of nitrogen. The Haber process created the synthetic fertilizer industry, and a global boom in agricultural productivity, dependent on fossil fuels extracted from the earth.
In the USA, dozens of companies produce nitrogen-rich fertilizer components at refineries that are fed by the nation’s network of natural gas pipelines. A few companies dominate the industry, but none more than CF Industries. CF stands for Central Farmers, and the company was established as a distribution network for a federation of agricultural cooperatives in 1946, when the post-war synthetic fertilizer industry expanded.
In the 1950s, CF began to produce fertilizer components (in addition to distributing them) with a nitrogen production plant in 1954, a phosphate complex in Idaho in 1955, and potash mining in 1958. By the late 1960s, CF was on its way to being one of the largest distributors and producers of nitrogen, phosphate, and potash products in the USA. In 2005 it ceased to be a cooperative, and became a publicly traded corporation. Since then it has sold its potash and phosphate operations, focusing on nitrogen production.
Though the company has several plants around the country, CF’s Nitrogen Production Complex in Donaldsonville, Louisiana, is by far the largest nitrogen plant in the country. The plant is located on the Mississippi River, in the nation’s principal petrochemical production area, a 100-mile-long stretch of river lined with industrial facilities between Baton Rouge and New Orleans.
Gas lines feed the plant, and nitrogen products, in fluid and solid forms, are shipped out by railcars, trucks, and ships. The plant is connected to the Gulf Central Pipeline, an ammonia pipeline built in the late 1960s, that connects plants and terminals in agricultural areas as far away as Nebraska and Indiana.
CF began nitrogen production at the big plant in Donaldsonville in 1966, expanding it in the 1990s, and again in 2016, when more than two billion dollars was spent on increasing its capacity. It now covers 1,400 acres and produces five million tons of nitrogen products for agricultural and industrial use. The plant produces ammonia and UAN (urea-ammonium nitrate), the most common forms of nitrogen fertilizer feedstocks, as well as granular urea, a solid form of fixed nitrogen. CF Industries operates several other significant nitrogen production facilities in the USA, including two in Oklahoma, one in Iowa, and another in Mississippi.
Nutrien is the second largest nitrogen fertilizer producer in the USA. It was formed in 2018, with the merger of two Canadian companies, the Potash Corporation, and Agrium, both of which were already among the largest NPK fertilizer companies in the world.
Nutrien operates a nitrogen plant in Geismar, Louisiana, on the Mississippi River, a few miles upstream from the big CF facility at Donaldsonville. The company operates other plants in Lima, Ohio; Augusta, Georgia; Kennewick, Washington; and Borger, Texas. Borger is a convergence point for many petrochemical products pipelines, including the Mid-America pipeline, that carries ammonia from the Nutrien plant to the Upper Midwest, and connects to other nitrogen plants in Oklahoma, Nebraska, and Iowa.
Koch Fertilizer, LLC is the third largest producer of nitrogen fertilizers in the USA, and is part of Koch Industries, the multi-national energy and chemical company owned by the notorious Koch brothers, and often ranked as the second largest privately held company in the USA (after Cargill). Koch got into nitrogen in 1988, when it purchased ammonia pipelines that connect many of the plants in the USA with distribution terminals, such as the nitrogen fertilizer plant in Beatrice, Nebraska, which is located on the Mid-America Pipeline, a six-to-eight-inch-wide ammonia pipeline that runs from Borger, Texas to Mankato, Minnesota, more than 1,000 miles away.
Koch also operates a nitrogen plant near Fort Dodge, Iowa, located on the Gulf Central Pipeline, one of the longest pipelines of any kind in the USA, which runs for 1,900 miles, connecting nitrogen plants along the lower Mississippi to terminals in cropland as far away as central Nebraska and Indiana.
Though nitrogen fertilizer production in the USA is dominated by big companies like CF Industries, Nutrien, and Koch, dozens of other companies also produce the material in varying amounts. Trammo, for example, is a privately held international fertilizer commodities marketer, based in Manhattan, that operates terminals, train cars, and barges for ammonia, as well as a few plants. Another, Cherokee Nitrogen, operates a 160-acre plant on the Tennessee River, in Cherokee, Alabama, a few miles downstream from the former federal fertilizer research facility at Muscle Shoals.
The government’s plant at Muscle Shoals was the American center for industrializing the Haber process for fertilizer, and explosives, another important use of ammonium nitrate. In WWI, Muscle Shoals was likely the largest explosives production plant in the nation. After the war, with the coming of the Tennessee Valley Authority, the site was expanded into the Muscle Shoals Reservation, a diversified fertilizer and chemical production center, where more than 4,000 people worked at the peak of WWII. After that war, its phosphate production plants continued to make fertilizers, and chemical weapons. The innovations in industrial fertilizer production at Muscle Shoals were instrumental in creating the modern industrial agricultural revolution worldwide.
The chemical connection between nitrates for fertilizers and explosives are close, and several companies produce both, while others focus on one or the other. Apache Nitrogen, for example, was formerly known as the Apache Powder Company, and now produces ammonium nitrate for use as mining explosives, as well as for fertilizer at a plant located in a remote desert region of southern Arizona. Another company, the privately held Trademark Nitrogen Corporation, operates a nitrogen plant in an industrial park in Tampa, Florida, which supplies highly concentrated ammonium nitrate to explosives companies like Dyno Nobel.
Dyno Nobel—its corporate roots are with the Swedish inventor of dynamite, Alfred Nobel—is likely the largest explosives company in the USA. It operates two large ammonium nitrate plants in the country, one in Missouri, serving primarily the mining and quarrying industries in the south and eastern USA, and the other, in Wyoming, serving the larger-scale excavations of the west, including the coal mines of Wyoming’s Powder River Basin.
It is common for nitrogen plants to be sited within larger chemical production complexes, as they can symbiotically share feedstocks and byproducts. CVR Energy’s nitrogen plant in Coffeyville, Kansas, for example, is next to its oil refinery. This plant is unique because it uses petroleum coke, a byproduct from the oil refinery, to make the hydrogen component of ammonia (instead of natural gas, which is typically used to do this).
Another example is AdvanSix’s chemical plant in Hopewell, Virginia. The plant is one of the largest producers of caprolactam, a feedstock for nylon. The creation of nylon (invented by the explosives and chemical company DuPont), involves a lot of nitrogen-related material, including ammonia, so the site is also a major producer of ammonium sulfates used for fertilizer.
In 2018, BASF and Yara opened their jointly owned $600 million ammonia plant at BASF’s chemical complex in Freeport, Texas. The plant uses hydrogen (produced at the massive Dow Chemical plant next door) to make ammonia, instead of using natural gas. BASF, a German company that is often ranked as the largest chemical producer in the world, was the company behind the Haber process, initiating the large-scale production of synthetic nitrate fertilizers in the first place.
The Basic Elements of Fertilizer: NPK
Phosphorus is essential to root growth and other plant functions. It is naturally found in most soils, but in limited amounts. Therefore, soil is commonly enhanced with fertilizers, including phosphorus (the P in NPK). Phosphorus can be found in things like bone meal, but the largest source is from phosphate rock deposits, associated with ancient sea beds.
The United States was the world’s largest producer of phosphate rock from the end of the 19th century until 2006, when US production was exceeded by China. Today the US still supplies more than 20% of the world’s phosphates, and 75% of that comes from one region in central Florida called the Bone Valley. The Bone Valley phosphate formation underlies hundreds of square miles in central Florida, a region that has been transformed by a hundred years of phosphate mining.
Dozens of companies have been active here in that time. Engaged in strip mining, draglines (giant shovels on cranes) are used to uncover the layer of phosphorus rock that lies ten to 50 feet below the surface, to dig it out for further processing into fertilizer. This being Florida, groundwater is just a few feet below the surface, and the process of extracting the rock is a wet one. Puddles, pools, and ponds of curious shapes are created, making a complex landscape.
Increasingly, reclamation has gotten more organized, and the land is often leveled and reengineered for reuse, as tomato fields, golf courses, wildlife areas, recreational parks, and other developments. Much, however, remains off limits, as the residual effects of phosphate processing leaves chemical remains, which have to be contained almost perpetually.
Companies that have operated here over the years include ARCO, Agri-Chemicals, Beatrice, Cargill, Conoco, Conserv, Estech, Kaiser, Kerr-McGee, IMC, PPG Industries, the Williams Companies, and CF. After decades of mergers and acquisitions, today the Bone Valley is basically owned and operated by one company, Mosaic.
Mosaic is a new company made up of old companies, formed in 2004 by merging Cargill’s crop nutrition division and IMC Global, both of which were already among the largest fertilizer companies in the nation. Headquarters are in Plymouth, Minnesota, just a couple miles up the road from the headquarters of Cargill, which remains the nation’s largest privately held company. The merger instantly created the largest US-based producer of potash and phosphate fertilizer.
Mosaic owns almost 300,000 acres in the Bone Valley, and leases the rest of what it needs, with expansion plans for two more mines in the southern end of a mined and potentially mineable area of 40 by 80 miles. Mosaic operations officially list two active production plants in the Bone Valley, fed by four active mines; however, the company keeps busy throughout the region, managing dozens of former mines, ponds, tailings piles, plants, and waste sites, covering hundreds of square miles.
Each mine is really a network of surface excavation areas, overburden storage, water retention ponds, berms, ditches, pipelines, pumping facilities, and preliminary processing plants.
The first step in the mining process is to dig trenches and berms around the immediate area to be mined, so that some of the groundwater drains into the perimeter ditch, keeping the mining area from becoming more of a mud puddle than it already is.
Then draglines remove the sandy soil that covers the ore body, some ten to 50 feet below. Mosaic has around 20 draglines in the area. The company says they are the largest earth-moving machines on the planet. They run on 72,000 volts of electricity, and have two operators.
After the outer layer of overburden is moved to the side, draglines extract the ore body, known as the matrix, which is around 1/3 clay, 1/3 sand, and 1/3 phosphate rock. Each scoop of matrix is dumped in a pool, where high-powered steerable water-jets break down the material into a slurry. The slurry goes in a 20-inch pipeline to the beneficiation plant.
Each mine site has a beneficiation plant, a large facility, which, by washing, screening, flotation, and other means, separates the sand, clay, and ore. The sand is stored until it is used for filling in mine pits, and the clay goes to clay ponds, as a slurry.
The clay ponds are generally around a square mile in size, and grow to be 40 to 50 feet tall, as more and more clay is deposited. The water leaches out of the clay into pipes controlled by a valve at the bottom of the pond. The clay ponds are also used to store water, which helps keep dust down.
The phosphorus rock material, separated and dried at the beneficiation plant and in granular form, is shipped by train to processing plants, to be turned into fertilizer products. Other source material is moved by slurry pipeline, where it is dried out at the processing plant.
The initial material produced at Mosaic’s processing plants is phosphoric acid, which is created by combining processed phosphate rock with sulfuric acid. Sulfur for creating sulfuric acid comes to the plants by rail or truck from oil refineries, where it is an abundant byproduct. Mosaic owns a sulfur terminal in Houston (for shipping sulfur) and another in Tampa (for receiving it).
The principal finished product produced at these plants is diammonium phosphate (DAP), which is made by combining phosphoric acid with anhydrous ammonia. This combination produces slurry, which is pumped into a granulation plant and mixed with more ammonia to produce DAP, a solid granular product that is applied directly or blended with other solid plant nutrient products such as urea (N) and potash (K). It takes more than 1.5 tons of phosphate rock to make one ton of DAP. Most Mosaic plants also produce monammonium phosphate (MAP), which is similar to DAP, but has more phosphorus. The plants also produce a bulk fertilizer product called MicroEssentials, an ammonium phosphate product with additional micronutrients, like sulfur and zinc.
When phosphate rich ore is mixed with sulfuric acid to make phosphoric acid, it produces phosphogypsum as a byproduct, which is piled high at these plants in a waste mound known as a gypstack. The material arrives as a slurry, and a liquid pond is usually present at the top of an active gypstack.
Mosaic has two currently active processing plants in the Bone Valley (the Bartow Facility, and the New Wales Plant), as well as some plants on standby. It also has major production plants outside of the Bone Valley, including the Riverview Plant, on Tampa Bay. Because of Mosaic’s operations inland and on the shore, Tampa Bay is the largest port for phosphates and nitrates (ammonia) in the nation. Mosaic’s Tampa Marine Terminal is a storage and shipping facility, used for the export of DAP and MAP, the two primary phosphate fertilizers it produces at its three active central Florida plants. From here the material is shipped by barge around the Gulf Coast, and up the Mississippi to the corn belt and other agricultural areas.
Mosaic uses facilities at the port to receive and store the large amounts of anhydrous ammonia it needs to make phosphoric acid and other products at the plants. One of these is the Hookers Point Terminal, acquired from CF Industries, with a 38,500-ton ammonia storage tank and a deep water dock. The terminal is connected to a 75-mile underground pipeline system that delivers ammonia to the Riverside Plant, and to the other plants in the Bone Valley. Ammonia is normally a gas, so it is kept pressurized in order to condense into liquid form for storage and transport. Around two million tons of ammonia comes into the Port of Tampa in this form every year, to feed Mosaic’s production. The ammonia comes by tanker ship from Mosaic’s ammonia production facility at Donaldsonville, Louisiana, and from other nitrate companies, like CF Industries.
Mosaic is not the only phosphate fertilizer company working in Florida and Louisiana. Though it is more prolific in its production of nitrogen and potash fertilizer products, Nutrien is the second largest phosphate fertilizer production company in the USA. It operates two mining areas, one in Florida, and the other in North Carolina, as well as one in Canada, where the company is based. These facilities were previously operated by the Potash Corporation until 2018, when Nutrien was formed by the merger of that company and Agrium, its chief competitor.
Nutrien’s Florida operations are in the northern part of the state, near the border with Georgia, and cover a ten by ten square mile region around White Springs, most of which has literally been turned over by years of strip mining phosphates, with two separate production plants. Nutrien is also the new owner of PotashCorp’s phosphate mine and plant in Aurora, North Carolina. Not as vast as the northern Florida site, the Aurora operation, measuring six miles by six miles, is large enough to be called the largest integrated phosphate mining and chemical plant in the nation, since it has just one plant, surrounded by its mines and waste ponds and piles. The mine produces around five million tons of phosphate ore a year, which the plant turns into around one million tons of phosphoric acid.
There is another cluster of phosphate mining and fertilizer production in the western United States, centered around a remote corner of southeastern Idaho, where a Permian-age sea bed deposit known as the Phosphoria Formation is mined. More than 30 mines have operated there over the last century. Today there are a half dozen or so active mines, operated by a few different companies, and they are small and scattered compared to the operations in Florida and North Carolina.
Three large processing plants process the phosphates produced by these mines. One of them is the Conda Phosphate Operation, near Soda Springs, which produces approximately 540,000 tons per year of mono-ammonium phosphate, super phosphoric acid, merchant-grade phosphoric acid, and other specialty phosphate products. It is owned by Itafos, a Canadian phosphate fertilizer company, based in the Cayman Islands. Itafos recently acquired the operation, including some of the mines in the area, from Agrium, after regulators required Agrium to divest itself of some phosphate assets in order to join with the PotashCorp to become Nutrien.
Nearby is Monsanto’s Soda Springs Phosphate Plant, which has been operating since the 1950s. It is currently supplied mostly by the Blackfoot Bridge Mine, the latest of several mines that have supplied the plant over the years.
Monsanto, based in St. Louis, is one of the largest and longest lasting agrochemical companies in the USA, notorious in more recent times for genetically engineering crops controlled by its branded herbicides. In June 2018, the company was officially sold to Bayer, the German life sciences corporation, which announced that it would be discontinuing the use of the Monsanto name.
Despite the end of “Monsanto,” it is expected that the plant will continue to operate, as its capacities are unique, producing elemental phosphates used for foods, chemicals, fertilizers, and the company’s signature herbicide, Roundup. As a functioning superfund site, it will have to be maintained as an environmental management site for a while to come. Over the years its gypstack has been a local attraction, as cauldrons of glowing molten slag can sometimes be seen being dumped over the edge of the continuously growing mound, and flowing down like lava.
The third big phosphate plant in the region is the Don Plant, in Pocatello, operated by Simplot, with a growing black gypstack behind it, too. The plant has been operating since 1944, when it was the first fertilizer production facility built by the J.R. Simplot company. It produces more than a million tons a year of phosphate fertilizers, feed phosphates, and industrial products from around 1.7 million tons of phosphate ore annually, which comes from its Smoky Canyon Mine, in southeast Idaho, next to the border of Wyoming.
Simplot’s Smoky Canyon Mine was developed in the mid-1980s and has a beneficiation plant on site, which refines and grinds the ore into a powder. It is then mixed with water and moved via an eight-inch-diameter pipeline to the Don Plant, 86 miles away.
The Don Plant is the largest of four fertilizer plants operated by J. R. Simplot. Another is an isolated facility outside of Rock Springs, Wyoming, where the company makes monoammonium phosphate (MAP), as well as phosphoric acid. The Rock Springs plant was built by Chevron in the mid-1980s, and was taken over by Simplot in 2003. The company recently built a $300 million ammonia plant at the site, which supplies the Don Plant with ammonia too. The phosphate ore for the Rock Springs Plant comes from a mine north of Vernal, Utah, and is conveyed to the plant through a pressurized slurry pipeline 96 miles long.
The Basic Elements of Fertilizer: NPK
Potassium facilitates growth, photosynthesis, and other critical functions in plants. For fertilizer, it is mostly extracted from potash, which is found in salt deposits underground and on the surface (potassium’s elemental symbol K is derived from kalium, Latin for alkali).
Of the millions of tons of potash fertilizer used in the USA annually, most comes from other countries, especially Canada. 15% or so comes from domestic mines, and nearly all of that from three underground mines in southeastern New Mexico, with a little more from around the Great Salt Lake in Utah.
Three mines, producing 80% of the potash in the USA, are in the Carlsbad Basin, in the southeast corner of New Mexico. Potash was discovered here in the 1920s, and underground mining was underway substantially by the late 1930s, when the federal government set aside 43,000 acres to encourage potash mining over other uses. After a boom in production spurred by demand for explosives in WWII, the federal Designated Potash Area was expanded to cover nearly 500,000 acres. Oil and gas production, active in the region, has noticeably fewer wells inside the Potash Area.
Over the years mines and processing plants have opened and closed in the area, and mining companies have changed names and ownership. Today two companies own and operate the mines, which have left an interconnected complex of rooms and pillars a thousand feet below the surface, under an area that is around 20 by 25 miles in size.
The largest of these operations is the potash mine and plant at Laguna del Sol. This plant and mine complex was operated for decades by IMC Global, which is now owned by Mosaic. Based in suburban Minneapolis, Mosaic, the largest US-based producer of phosphates, is also the largest US-based producer of potash. This, though, is the only potash mine owned by the company in the USA (most of its potash comes from mines in Saskatchewan).
The mine has been operating since 1940. It extends horizontally underground more than 12 miles from the plant, which sits on top of the main shafts. 700 people work at the plant and underground, running ten continuous mining machines, cutting out langbeinite and sylvite ore from two separate mine layers, around a thousand feet below the surface. This is turned into more than a million tons of potassium fertilizer products annually.
Mosaic’s operation is one of the largest underground mines in the nation, but it is smaller than the other network of mines in the area. This other network, under the northern part of the Designated Potash Area, has a number of connected mines, most of which are now owned by another company, Intrepid Potash. Intrepid, based in Denver, is the only US company dedicated solely to producing potash in the USA, and produces more than anyone else, from these two mines in New Mexico and two in Utah.
Located a few miles up the road from Mosaic’s plant is Intrepid’s West Mine facility, with two shafts connecting to a mining area with around 13 square miles of underground rooms and pillars. Above ground is a plant and a tailings pile covering a square mile. Opened in 1931 by the American Potash Company, this was the first potash mine in the region. Later it was owned by the Mississippi Chemical Company, until 2004, when it was purchased by Intrepid.
Over a period of more than 80 years, the West Mine extracted and crushed sylvite rock, which was turned into muriate of potash (the most common form of potash fertilizer) at the West Plant, and shipped by truck to the nearby North Plant for final processing and storage. In 2016, Intrepid placed the facility on care and maintenance status, idling mining there indefinitely, focusing its operations on other mines in the area.
Near the West Mine is a set of evaporation ponds covering a square mile. Intrepid built them a few years ago as part of a new potash mining operation known as the HB Solar Solution Mine, a hydraulic mining operation. The evaporation ponds hold water that has been pumped through flooded underground mines, dissolving ore from the walls and pillars, to settle and dry out here. After a year or so the dried residue is scraped up and processed into potash fertilizer.
Construction on the HB solution mine project began in 2012, and is costing up to $300 million, as it involves miles of pipelines and other infrastructure, including six injection wells that pump salt water into disused underground mines, and five extraction wells that pump it out and convey it to the ponds.
Four disused underground mines, including the Eddy Mine, connect underground, in a complex that covers nearly 50 square miles of room and pillar space. The solution mine flushes water through the rooms, creating underground leach lakes that dissolve pillars that were left to hold up the ceiling, but which are no longer needed. Up to 200,000 tons of potash a year is expected to be generated from the HB Solar Solution mining operation, for a run of 28 years. The company may expand the solution mining operations to cover more of the abandoned mine workings in the region, if all goes well.
Intrepid’s East Mine is an underground potash mine started by Kerr McGee in 1965. It was part of Mississippi Chemical’s operations when it was purchased by Intrepid in 2004. The East Mine is the largest of the underground mines in the area now owned by Intrepid. Around 25 square miles of room and pillar space has been excavated, and connect both the North and the West Mines. The working mine walls can be six miles from the shaft sites, making for long underground commutes for workers.
Still a dry mine, a few hundred people work in the East Mine, and mill. It stopped producing muriate of potash in 2016, and now focuses on mining the langbeinite ore body layer, which produces a more valuable form of potash with a lower chloride content, favored by higher value crops like citrus, vegetables, and sugarcane.
Intrepid learned about in-situ solution mining, which it applied in the HB Solution Mine project in New Mexico, at its mining complex outside of Moab, Utah, the Cane Creek Mine. In 1963 the TexasGulf Company opened Cane Creek as an underground potash mine, seeking to diversify from its increasingly obsolete sulfur operations in Texas and Louisiana. Soon after the mine opened, 18 people died in an explosion 3,000 feet below the surface.
It was converted into a solution mine in 1970, using water from the adjacent Colorado River to flush out the potash, no longer requiring people to work underground. Intrepid (Intrepid Oil and Gas Company at the time) bought the mine in 2000, and changed its name to Intrepid Potash. The mine can produce between 75,000 and 120,000 tons of potash annually, depending on evaporation rates, which vary widely, depending on temperature and rainfall.
After purchasing the Cane Creek Mine, Intrepid went deeper, and shallower, into potash, acquiring underground mines in New Mexico, and a surface mining operation in Wendover, Utah.
Wendover’s potash production dates back to WWI, when the Utah Salduro Company extracted potash here from 1917-1921. After that, operations ceased until WWII. In 1939 operations began again, expanded into almost 100 square miles of ponds and canals. Kaiser Aluminum and Chemical Corporation took over operations in 1964. When Intrepid took over in 2004, the mine was owned by Reilly Industries, one of the few remaining family-run chemical companies, which dissolved the following year.
The process involves around 100 miles of ditches, 20 feet deep, dug into the salt flats. With the water table just a few feet below the salty and muddy surface, the ditches immediately fill with water containing the dissolved minerals of the region held in solution. The ditches lead into a central canal—the mother canal—which ends at a pumping station.
The water is pumped into a network of evaporation ponds, first dropping out salt, which is scraped off and sold or dumped. The water moves on to a harvest pond, where it dries into a briny potash slurry, and then is scraped up and taken to the plant where it is crushed, flotated, and dried to become muriate of potash.
For more than 50 years, the plant has produced between 65,000 and 100,000 tons of potash a year, depending on the weather (especially rain, which dilutes the ponds).
The nearby Great Salt Lake, at the bottom of the Bonneville Basin, is a terminal lake, with no drainage to the ocean. All the minerals from the surrounding mountains fall into it, layering onto its bottom, or dissolving in its water, which becomes fully saturated with minerals by the relentless evaporation from the sun and dry air. And so, the waters of the lake itself are a mineral resource, mined by a few companies, including one that extracts potash in an elaborate, vast, and flat mining process.
On the northwest end of the lake, where the water is made even saltier by the railroad causeway that divides the lake in half, the Compass Minerals Company pumps water from the lake into evaporation ponds next to the lake, in an area known as Clyman Bay. After the heat and dry air of the region further concentrates the water in this pond, it is released into a canal heading east into the lake.
The canal continues across the lake, underwater, cut into the bottom, and continuously sloping downwards, as it heads eastward. Because brine released from the pond is denser and heavier with salts, it stays inside the canal, flowing slowly—water within water. The canal, called the Behrens Trench, was built in 1991 by the Great Salt Lake Minerals and Chemicals Company, which operated the salt and potash plant on the lake at that time. It is unique in the nation, if not the world. Dredges keep it maintained.
Taking a week or so to ooze its way to the other side (a distance of 21 miles) the brine is pumped out of the east end of the trench and over the railroad tracks of the causeway, into a more normal canal heading east along the shore of Promontory Point. The canal system ends at the older and larger pond complex at Bear River Bay, next to a potash plant that has been operating here since the late 1960s.
Here the lake brine, with additions from the more immediate waters of the lake, is slowly cooked, taking up to two years to reach the right concentration. The pregnant brine then enters the plant, where it is processed into sulfate of potash, a form of potash fertilizer that is used on high value crops, like fruits and nuts. Much of it is purchased by citrus growers in Florida.
Compass Minerals, based near Kansas City, took over the operation in 2003, and makes around 350,000 tons of sulfate of potash fertilizer here annually. They also produce a couple of million tons of salt, used on roads and in industry.
The two antithetical products, salt and fertilizer, one which helps plants grow, the other which kills them, come from the same salty place, and are separated from one another to perform disparate functions. Eventually, of course, they merge again, as nearly everything does, in the oceans that cover the planet. ♦
Industrial fertilizer in America was the subject of an exhibition at the CLUI in Los Angeles from August 10-December 23, 2018, called The Ground Our Food Eats: Industrial Fertilizer Production in the USA.