New Underground Technology Mines One of World’s Oldest Chemicals

If you grow it, process it, eat it, wear it, clean it or cleanse with it, watch it, listen to it, ride in it or ride on it, somewhere along the line soda ash derived from trona is involved. While the use of soda ash dates back more than five centuries, its modern source—from mined trona—is measured in mere decades.

After salt and lime, soda ash is the third chemical known to have been used by man, dating back at least 3,500 years to the Egyptians who extracted it from wood ashes—hence the name. Today, soda ash from trona is involved in virtually every aspect of life, through the manufacturing of glass, in chemical manufacturing, fertilizers, soaps and detergents, pulp and paper, flue gas desulferization, and water treatment.

It wasn’t until 1791 that LeBlanc discovered the process for extracting soda ash using sulphur, salt, and coal gas; and 1860 that Ernest Solvay modified the process to achieve a better soda ash using brine, ammonia, salt, coal gas, and carbon dioxide.

In 1938 trona was found in a core sample while drilling for oil at the John Hay No. 1 Well south of Westvaco, Wyoming. Trona was first deep-mined in 1947 by Westvaco Chlorine. Shortly after that, FMC Corp. acquired Westvaco’s chemical business, including the mine, and then added the Granger mines. Today, Philadelphia-based FMC is the world’s largest natural soda ash producer. The company, founded in 1883, maintains a leading position in three chemical markets: agriculture, specialty, and industrial. 

Wyoming trona is also mined by General Chemical Industrial Products, Solvay Minerals, and OCI Chemical. The beds in which they all operate began forming 50 million years ago when deposited volcanic ash later was covered by Lake Gosiute, which reportedly once spread over a 15,000 square-mile area. The deposits resulted in more than 42 beds of trona in the Green River Basin of southwest Wyoming, stretching from the Uintah Mountains of Utah in the south, along the Wyoming Range to the west, the Rock Springs uplift to the east to the Wind River and Gros Ventre Mountains in the north.

Beginning in the 1950s, soda ash from trona steadily replaced Solvay “synthetic” soda ash in the U.S., with the last Solvay plant closing in the 1970s. Today, more than 90% of the soda ash used in the U.S., along with more than 30% of the world’s supply, comes from Wyoming,.

In the Green River Basin, 25 of the thickest beds contain 127 billion tons (115 billion mt) of trona with 40 billion tons considered recoverable—sufficient for 2,350 years of extraction at today’s rate of mining. Bed 1 is 3,500 ft (1070 m) beneath the surface and Bed 25 is 800 ft (245 m) down.

Typically, trona is processed into soda ash (sodium carbonate, Na2CO3) at a recovery rate of 1 ton of soda ash for every 1.7 tons of trona. Industry-wide, Wyoming trona mines employ more than 2,225 people, annually mining more than 17 million tons (15 million mt) of trona to produce more than 10 million tons of soda ash, shipped from the mine by rail bagged or in bulk.

About 44% of the trona in Wyoming is produced from federal owned lands and some 56% from state and private lands, all of it deep-mined using boring machines with continuous haulage, continuous miners with continuous haulage and shuttle cars, and, at the Solvay and FMC mines, longwalls.

The most successful application of longwall mining has been at the FMC Westvaco Mine. “Here, we have 225 people involved in the mining some 4.6 million tons of clean soda ash,” said Tim Davis, senior mine engineer and longwall project manager. “We run 10 hour shifts, 24 hours a day, 7 days a week, usually 11 production shifts a week, and six or seven maintenance shifts.

“Presently,” Davis said, “we have two borer miners on longwall development work and a third machine working on our bleeders, all working in tandem with JOY 10SC-32 shuttle cars. The shuttle cars dump onto conveyor belts that transport the trona to skip hoists for transfer to the surface and the processing plant.

“Unlike in coal mining,” Davis explained, “in addition to the headgate and tailgate, we drive a third entry up the center of the longwall panel, about 125 feet from the headgate, then mine through those pillars as we advance the longwall.”

Westvaco’s longwalls typically measure 750 ft (230 m) across the face by 9,400 ft (2865 m), with 1,600 ft of cover. According to Davis, two problems in mining trona can be excess water and the size of the material as it comes off the longwall face.

“For one thing, trona is water soluble. When we get it outside, the first thing we do is calcify it, drive off the water, so the less water the better. Also, when trona and water do mix, it runs into places you don’t want it to run and then sets up like concrete,” Davis added. “Fortunately, while extracting trona does generate dust, it is a nuisance dust, not a hazardous dust, so we don’t have to use as much water for dust suppression, as they do in coal mining.

“The second problem we encounter is the size of the slabs of material that comes off the longwall face,” Davis continued. “While we continue to work on that problem, making adjustments to the shearer, the shield operators still have to, at times, break up large slabs using jackhammers.”

As explained by Davis, FMC’s Westvaco mine is 1,550 ft (475 m) below ground and has more than 2,500 miles (4000 km) of tunnels stretched out over 36 mi2. Entries are 16 ft (5 m) wide, 9 ft (3 m) high and the mine operates at 1,000 t/h, with an additional 100 t/h per hour coming from a unique solution mining process involving the injection of water in another area of the mine.

According to Scott Lewis, Joy sales engineer, “Allied Chemical (now General) pioneered longwall mining of trona in 1973. FMC began longwall mining in 1981. Longwall mining was halted briefly in 1987 for retooling. In 1993, the mine replaced the longwall system with a Joy longwall system, adding a JOY 6LS5 shearer in 1996. Now equipped with a Joy 7LS5 shearer, the current longwall is recovering 50% more of the in-seam trona than the mine had been realizing in borer mining.”

Along with the Joy 7LS5 shearer, the FMC Westvaco longwall installed this past January consists of 131 Joy 2 x 870-ton shields, 2 x 1,000-hp Joy armored face conveyor and 42 x 146 flat link chain, and a 450-hp stage loader with a 42-mm Joy Broadband low-profile chain. The longwall system also features Joy’s Faceboss control platform.

According to Lewis, “With a combination of assistance tools, Joy’s Faceboss control platform provides the operator with automated cut sequence settings, advanced diagnostics with on-board graphic displays, and machine performance monitoring and analysis. Combined, this system ensures the operator can achieve the optimal balance of production rate and cost.

“Since its introduction in 2006,” Lewis added, “the Faceboss control platform has proven so successful that today it is standard on all Joy 7LS shearers, as it is on all continuous miners, flexible conveyor trains, and armored face conveyors.”

Cats on a Long Hot Road

Recent events and coverage have raised Mongolia’s profile a notch or two with the general public in some Western countries, but this Far Eastern nation is still an adventurous choice for most travelers. Especially if you are driving a 102-ton mine truck.

Energy Resources, one of perhaps 200 Mongolian and foreign-owned mining companies operating in the country, needed seven new Caterpillar 785C haulers delivered to the new Ukhaakhudag coal mining operation in southern Mongolia. The project is near Tavan Tolgoi, where coal has been mined since 1967. Caterpillar and Wagner Asia, the company’s dealer covering Mongolia, were happy to oblige. However, while del;ivery from the Decatur manufacturing plant in Illinois, USA to China and then on to the Mongolian border was more or less standard procedure— they were shipped from the US to Xingang, China, trucked to the Mongolian border and assembled—the final transit to Ukhaakhudag certainly was not, Caterpillar reports.

The first two trucks arrived at the border-crossing town of Dzamin Uud where Wagner Asia technicians assembled them for the 650-km trip to the mine site. The journey to the mine required two drivers as well as the technicians, accompanied by Battur, sales director for Wagner Asia (Mongolians have no inherited surname).

“We drove across the Gobi desert, there’s nothing out there but bare wilderness. There was no other way to deliver these trucks to the mine. It took us in total 48 hours, and we camped in a tent the night between the departure and arrival,” said Battur. But he added that it was not only for the Wagner Asia personnel that this adventure was unforgettable: “At one point we drove past a camp of herders. A man came out of one of the gers—a traditional nomad dwelling—and you could tell he was really astonished and even a bit frightened by the massive machines driving by. It’s not every day you see a mining truck thundering past your backyard!”

Perhaps the herders are getting used to these visitors. A month later three more of the trucks followed the first two and the remainder will follow by the end of 2009. The 785C mining truck has an operating weight of 102 mt and is more than 11 m long, 5 m tall and 6 m wide.

Although Mongolian companies are eager to develop the country’s extensive and varied coal and mineral resource base, financial and technical resources are quite limited. For these reasons Energy Resources is on the one hand being backed by the EBRD, which is putting equity into the company, and has on the other signed an agreement with the Australian-based Leighton Mining Contractors group for the provision of various services. Under this agreement, arranged via the Leighton Asia office in Beijing, Leighton Mining and Infrastructure Mongolia Ltd. will undertake removal of overburden, mining of coal and provision of mine planning and engineering services for a six-year period starting in March this year. Leighton, which set up an office in the Mongolian capital Ulanbaatar during 2007, said the deal is the result of continuing cooperation between the two companies.

US coal producer Peabody completed a buy-in to Mongolian coal development in May when it acquired a 50% interest in the holdings of Polo Resources, creating Peabody–Polo Resources B.V. Meanwhile Vancouver-based SouthGobi Energy Resources is ramping up production at the Ovoot Tolgoi mine.

Normet: Best Year Ever in 2008

For Finland’s Normet Group, results for 2008 were the best this manufacturer of mining and tunnelling machinery has ever achieved. Turnover reached €107 million, representing a growth of 38%, and the value of orders rose by 43% compared with 2007. With 83% of sales being made outside Europe, the company’s reorganization in 2007 proved to be an immediate success. The number of employees increased by some 30%, and at year-end just exceeded 450 people. Normet will continue its expansion activities during the recession. New sales and service companies will be established, product development resources will be increased, and the development of the service business will be further strengthened.

“Signs of a declining mining market started to show from November 2008. However, operations in the tunneling market remain active, as many countries allocate their development programs to infrastructure projects. The demand for Life Time Care services has likewise remained at a good level,” said Jari Osmala, CEO of Normet. “During the early part of this year, Normet’s turnover has slightly increased compared to last year. We started the year with a good order book from last year and have also received a fair amount of new orders thanks to the booming tunneling market.”

During 2008, Normet continued the development of its international operations and currently counts 23 locations in 15 different countries around the globe. Two corporate acquisitions involved Semmco in Chile, a manufacturer of concrete and sprayed concrete equipment, and Rock-Tek in the US, a specialist in spare part and service operations.

“The next step will be to deepen our knowledge of the customer processes and to expand our offering accordingly. The objective is to continuously increase the added value which the customer obtains from his Normet investments in his work processes,” said Aaro Cantell, chairman of the board of Normet Group. “Normet wants to be the global top-of-the-range expert in sprayed concrete and explosive charging processes and to provide customers with solutions to improve productivity, safety and added value,” added COO Tom Melbye.

“The duration of the global financial crisis is still unknown, but the need for underground mining operations and infrastructures will continue, and will grow rapidly," concluded Osmala.

Behre Dolbear Expands Consulting Services with A&S Acquisition

Behre Dolbear Group has acquired the assets of management consulting firm Anderson & Schwab, Inc., through its subsidiary, Behre Dolbear Management Consulting.

Anderson & Schwab, with offices in Australia, Canada, and the United States, offers a broad variety of management consulting services to the international minerals and coal industry. The firm's focus is to assist top management of producers in its decision making in areas of strategy, corporate development, business analyses, management organization planning, management controls, management development, executive compensation, asset sales and purchase, acquisition search, general problem solving, and executive staffing.

Behre Dolbear is a minerals industry advisory firm providing advisory and consulting services in the technical, financial, managerial, and business-related aspects of the industry.

Boart Longyear Sheds Some African Assets

Boart Longyear announced the sale of certain of its sub-Saharan African operations to Tranter Energy and Mining Services, a subsidiary of Tranter Holdings.

The business, to be renamed Tranter Rock Drills, consists of Boart Longyear’s percussive rock drills and hard rock tools product lines for sub-Saharan Africa as well as all manufacturing operations located in Roodepoort, South Africa. The business generated approximately $14 million in revenues in 2008. As a result of the sale, all 260 employees associated with the business are transferring to Tranter Rock Drills.   Boart Longyear will continue to supply rock drills and hard rock tools outside of the sub-Saharan Africa region, and under the terms of the sale, Tranter Rock Drills will become Boart Longyear’s exclusive supplier of rock drills for a two-year period.

Johannesburg will remain as the sub-Saharan Africa regional sales headquarters for Boart Longyear along with its distribution point for the region for exploration drilling products as well as drill rigs and consumables for the construction, overburden and percussive drilling industries. In connection with the sale, the company expects to record a one-time, non-cash charge of approximately $3 million in the first half of 2009, primarily related to foreign exchange losses.

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