Rock mechanics issues in the trona patch agapito associates. National institute for occupational safety and health niosh conducted two controlled recirculation tests over three days at a wyoming trona mine, utilizing an inline booster fan to improve airflow to a remote and difficulttoventilate development section. The diagram below shows how mined trona is refined into soda ash using the mono process. Apply to environmental engineer, miner, maintenance person and more. The method has an average 45% mining recovery, which is higher than the 30% average mining recovery from solution mining. The trona mines in the green river basin, commonly known as the trona patch, present an interesting set of rock mechanics issues stemming from mining in a unique underground environment. It is used to remove sulfur from both flue gases and lignite coals. Cdc mining case study of controlled recirculationat at. There are 4 distinct methods used to mine the wyoming trona ore. Us2388009a us506841a us50684143a us2388009a us 2388009 a us2388009 a us 2388009a us 506841 a us506841 a us 506841a us 50684143 a us50684143 a us 50684143a us 2388009 a us2388009 a us 2388009a authority us united states prior art keywords trona brine formation solution sodium prior art date 19431019 legal status the legal status is an assumption and is not a legal conclusion. All the wyoming trona mines use room and pillar mining with multiple entry systems. All of the current mining activity is concentrated in the northern part of the trona district. Application of the solution mining process to the turkish. Turkish trona deposit the turkish trona deposit was discovered by the mineral research and exploration institute mta in 1979 during coal exploration.
Trona is a sodium carbonate compound, which is mined and. Longwall mining involves dividing the seam into rectangular panels or blocks and cutting drifts along the sides of the blocks for material transport and ventilation. River basin since 1947 using numerous mining methods. Numerical analysis of longwall mining layout for a wyoming. It is the most common supported pillar method, designed and used primarily for mining. The recovered trona is then dropped onto a continuous conveyor system and moved to the surface. Longwall mining and roomandpillar mining are the two basic methods of mining coal underground, with roomandpillar being the traditional method in the united states. A field study of longwall mine ventilation using tracer. The museum will hosted a lecture and booksigning on the history of trona. Hustulid, editor society of mining engineers 1982 1794 pages. Mining industry response to the book continues to be incredible. From about 1957 to 1960, fmc tested the practicality of solution mining trona. In our current implementation of this technology, water and insoluble tailings are injected into mined out areas that still hold unrecovered trona.
Both methods are well suited to extracting the relatively flat coalbeds or coal seams typical of the united states. The market is anticipated to be driven by increasing demand for trona from animal feed, air pollution control, and soda ash industries. Mining methods, surface mining depend on wa ter or another liquid e. The open pit mining is a mechanical extrac tion method. Trona is a common source of soda ash, which is a significant economic commodity because of its applications in manufacturing glass, chemicals, paper, detergents, and textiles. Laboratory experiments were conducted to investigate the dissolution system and the crystallization parameters of these processes. One company operates in beds 19 and 20 and another company mines beds 24 and 25. Trona is a sodium carbonate compound that is processed into soda ash or bicarbonate of soda, or baking soda, as it is commonly known. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Taking into account the whole features of the deposit, it is possible to state that the turkish trona deposit is the second largest natural sodium carbonate formation in the world. Trona trisodium hydrogendicarbonate dihydrate, also sodium sesquicarbonate dihydrate, na 2 co 3 nahco 3 2h 2 o is a nonmarine evaporite mineral. It is a product of carbon sequestration of flue gases. Catastrophic failures of underground evaporite mines jeff whyatt, mining engineer floyd varley, acting branch chief niosh spokane research laboratory spokane, wa abstract deformation of underground salt, trona and potash mines is generally time dependent, providing for gradual adjustment of strata to mining induced stresses. Trona has been mined continuously in several mines in the green river basin since 1947 using numerous mining methods.
Laboratory experiments were conducted to investigate the. Underground roomandpillar mining, using a combination of conventional, continuous, and shortwall mining equipment, is the primary method of mining wyoming trona ore. The lqd regulates the permitting of coal production in the state. Classification of underground mining methods mineral production in which all extracting operations are conducted beneath the ground surface is termed underground mining. Concise guide to wyoming trona and soda ash wyoming mining. Like other minerals occurring in tabular deposits, trona is mined using highproductivity roomandpillar and longwall methods. This method has an average 45% mining recovery, whereas average recovery from solution mining is 30%.
These machines, traditionally used for coal mining, are custom built to cut the harder trona ore. There are maintenance shops, bathrooms, electricity lines, and streets. Comparison to synthetic methods of producing soda ash. It is also effectively used to reduce air emissions.
A ventilation research study was conducted by the national institute for occupational safety and health and a cooperating trona mine in the green river basin of wyoming, usa. In addition to mechanical mining, we developed and patented solution mining technology here. Although nahcolite may not have a significant effect on mining and processing the mineral for soda ash by the methods now used at the wyoming trona mines, its. Background ofthe invention a field of the inventionthe invention relates to the method of mining trona mineral in order to obtain gradual, controlled bending of the mine roof, as an integral layer, in the mined areas until these areas are completely caved in. Lecture on the history of trona and searles valley youtube. However, labor is costly, and manual mining tech niques are inefficient.
Political influence mineral deposits at the borders of two countries may not be exploited as a dispute may arise concerning whom mine it e. Tis lecture was given in the coso room of the maturango museum on wednesday, december 9,th. A crosscut connects the parallel drifts, along which the longwall cutter is installed. This study was conducted to investigate the applicability of the solution mining technique to the turkish trona deposit. Although widely used in other countries, longwall mining. Method of mining trona using a continuous miner us31732a us3116a method of mining trona using a continuous miner.
All trona is mined underground and then processed into soda ash or baking soda. In this study, 116 gigatons gt of trona ore are estimated to be present in 22 beds, ranging from 1. Roomandpillar mining the roomandpillar system involves extracting the ore by carving a series of rooms 20 to 30feet wide while leaving pillars of ore. At solvay mine, located in southwestern wyoming, a subhorizontal trona. It is mined as the primary source of sodium carbonate in the united states, where it has replaced the solvay process used in most of the rest of the world for sodium carbonate production. Unfortunately, they have not been nearly as successful as in civil tunneling. Case study of controlled recirculation at a wyoming trona mine. In its heyday, there was a movie theater, a big dance hall, numerous bars, telford said. The mine operation uses the longwall mining method in trona bed 17, a commonly mined unit in the region. This would require the injection of hot, pressurized water through a vertical injection hole connected to a 500 m long horizontal well drilled along the base of the trona 800 850 900 950.
Most trona is mined through a roomandpillar system where a series of parallel drifts are driven. Modern day heap leaching, which has a relatively low level of energy consumption, is for example. This study presents the results of an indepth analysis of in situ trona production costs by employing a process engineering approach. Underground mine design, planning and engineering maximize your ore reserve value by using our operating expertise to customize your mining plan we have years of firsthand underground mine engineering and operating experience in most countries and across multiple commodities using all common mining methods.
Magadi town which originated from the mining of soda ash. Typically, underground mining methods involve more electrical equipment than surface mining methods. Open pit mining mining methods 5 open pit mines are used to exploit low grade, shallow ore bodies. Numerical analysis of longwall mining layout for a wyoming trona. Solution mining impact assessment solution mining method using horizontal wells is planned to extract the trona ore because of its depth and lowgrade. Pdf evaluation of flotation technology for the trona industry.
For the room and pillar underground mining method, using the battery powered. The mine safety and health administration msha defines trona operations as gassy type iii metal nonmetal operations that liberate methane, often in significant amounts pritchard et al. Solution mining includes both borehole mining, such as the methods used to extrac t sodium chloride or sulfur, and leaching, either through drillholes or in dumps or heap s on the surface. The mining rate is greater than 20,000 tonnes per day tpd but is usually much greater. The trona industry in sweetwater county green river, wy. In addition to mechanical mining, we developed and. In the mining of a substantially horizontal bed of trona, stronger than the overlying and underlying strata, the method of driving substantially parallel entries into the trona formation, connecting said entries by at least one primary passage thereby defining the main trona pillar to be mined, supporting the roof of a primary passage by means of a movable roof supporting structure and mining. Wyoming trona industry overview wyoming legislature. Mar 07, 2016 the town was designed in 1914 to house the workforce of the american trona corp. Bedded trona na2co3nahco32h2o in the lacustrine green river formation of eocene age in the green river basin, southwest wyoming, constitutes the largest known resource of natural sodium carbonate in the world. Application of the solution mining process to the turkish trona deposit. For this purpose, sesquicarbonate and alkali extraction processes were applied to turkish trona. Mining industry soda ash mining a variety of mining methods are used in soda mining.
Coal, shales, potash, salt and trona encompass the majority of soft rock ores. The longwall method extracts 50 percent more of the trona deposit than traditional mining methods. Wyoming produces natural soda ash from four trona mining. One of the main sources of trona production in the green river basin is solvay mine, located in western wyoming, approximately 6. This thesis covers the determination of the dimensions of the initial vertical caverns formed in underground by use of a computer modeling trademark. Application of tunnel boring machines in underground mine. Evaluation of instrumented cable and rebar bolts as ground. Mining is a source of market for goods and services e. The trona in sweetwater county was created by an ancient body of water which became known as lake gosiute. The longwall face length is 228 m 750 ft, and caving on the face occurred up to the back of the longwall. Heap leaching is a tried and tested mining technique enabling the processing of different kinds of ores which could not otherwise be exploited under viable economic conditions.
The total reserve contains over 100 billion tons of trona, 40 billion tons are minable with conventional methods. The two industries ranked together as the primary or basic industries of early civilization. Sensitivity analysis for trona solution mining mineral. Classification of surface mining methods extraction of mineral or energy resources by operations exclusively involving personnel working on the surface without provision of manned underground operations is referred to as surface. Mining can be done if the mineral is in demand and if the prices are reasonable so that mining costs are offset and a profit is realised. The most common geographical layout for these ores consists of laterally extensive beds in a nearly horizontal inclination but with, at most, a shallow dip angle 25. The raw material for wyoming soda ash is mined trona ore, while california soda ash comes from sodium carbonaterich brine extracted from searles lake. An underground trona mine is like an underground city. Mining method trona is mined with a drumandborertype continuous mining machine. The mining process and equipment are very similar to roomandpillar coal mining, with permis.
Describe the occurrence and exploitation of trona in kenya till it is ready for marketing. Catastrophic failures of underground evaporite mines. Economics of trona solution mining was investigated for turkish trona deposit to offer comparative estimates of this method and conventional mining techniques. Five companies are presently mining trona in the green p. Trona interpretive plan3 the wyoming state historic preservation. With the loss of outflows, high amount of alkaline salt brine began to evaporate, depositing the beds of trona. Us3402968a us60323666a us3402968a us 3402968 a us3402968 a us 3402968a us 60323666 a us60323666 a us 60323666a us 3402968 a us3402968 a us 3402968a authority us united states prior art keywords trona pillars mined mining pillar prior art date 19661220 legal status the legal status is an assumption and is not a legal conclusion. Index map showing location of area of sodium carbonate brine and trona deposits. The earliest application of tbms in mining dates back to late 50s. Underground mining methods are usually employed when the depth of the deposit andor the waste to ore ratio stripping ratio are.
The first step in selecting the most appropriate mining method is to compare the economic efficiency of extraction of the deposit by surface and underground mining methods. Improved solution mining techniques, such as horizontal drilling to establish communication between well pairs, could increase this extraction rate and enable companies to. Some pits operate at a rate of more than 100,000 tpd. In the mining of a substantially horizontal bed of trona, stronger than the overlying and underlying strata, the method of driving substantially parallel entries into the trona formation, connecting said entries by at least one primary passage thereby defining the main trona pillar to be mined, supporting the roof of a primary passage by means of a. Thanks in large part to the efforts by john chadwick of the mining journal, and many other members of the mining community, the hard rock miners handbook has been distributed to over 1 countries worldwide.
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