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By William R. Yernberg

Santa Fe Pacific Gold, headquartered in Albuquerque, NM is expanding its operation at the Twin Creeks Mine in Nevada. The $250-million sulfide expansion project, including the Sage Mill, is under construction and is 80% complete. Also, additional mining equipment has been purchased to haul the sulfide ore to the mill. With the expansion, employment at Twin Creeks is expected to reach approximately 970 people by the end of 1996. Santa Fe Pacific Gold now owns and operates three gold mines in the United States and is involved in several other gold projects. The three currently operating mines are the Twin Creeks, Mesquite and Lone Tree mines. The Mesquite Mine is located in California’s Imperial Valley. Lone Tree is located 55 km (34 miles) southeast of Winnemucca, NV. The company’s total gold production from these operations is expected to be in the range of 26.3 to 26.6 t (845,000 to 855,000 oz) in 1996. This compares to a total production of about 124 kg (4,000 oz) for the company in 1989. Production costs range from $6.90to $7.25/g ($215 to $225/oz). At the end of 1995, the company reported proven and probable reserves of 556.7 t(17.9 million oz) of gold.

Jan 1, 1996

By Donald W. Gentry

This paper presents some of the results of a rock mechanics in¬strumentation program designed for, and implemented at, longwall panel 4N at the York Canyon Mine near Raton, New Mexico. The objective of this particular instrumentation program was to determine the response of the rock mass to longwall mining of a thick coal seam utilizing shield-type supports. Measurements were made in the rock along the ground surface, above the coal seam, in the coal seam and immediately below the coal seam. Longwall test panel 411 had a total developed length of 762 m (2500 ft) and a face width of 168 m (550 ft). The seam mining height in the panel area was approximately 3 m (10 ft). The average depth of overburden above the panel is 107 m (350 ft) al¬though it ranges from 73-134 m (240 - 440 ft). Roof support at the face was provided by Hemscheidt shields. These shield-type supports weigh 11.4 metric tons each.

Jan 1, 1977

By F. Djahanguiri

The U.S. Bureau of Mines is conducting research on underground stope leaching of metalliferous ores to minimize the environmental impact of ore processing on the surface and to maximize minable reserves. An aspect of this research is to minimize pregnant solution losses and/or groundwater contamination by leach solutions. Bulkhead design and construction are important issues for solution control and stope leaching economics. A reinforced concrete bulkhead was designed, constructed, and tested for solution control in an underground mine near Idaho Springs, CO. This paper presents the bulkhead design methodology and construction procedure.

Jan 1, 1995

By Derrick Chambers, George Kevin Chapin, M. Shawn Boltz

Seismic monitoring is one of the few noninvasive technologies with the potential to provide sub-surface geomechanical information to operators of large open-pit mines. Although passive seismic data has been used to refine emerging failure geometries and provide advance indication of surface deformations in the literature, doing so reliably in an operational context is much more difficult. This is due in part to difficulties in estimating and interpreting source locations and parameters in complex, low-stress open-pit environments. Additionally, the high costs associated with implementing, operating, and maintaining deep borehole seismic networks, which are most commonly used to monitor large open pits, can be difficult to justify, especially if monitoring benefits are not readily apparent. In this study, we explore the use of a near-surface nodal seismic deployment, which is commonly used in oil and gas exploration, for monitoring open-pit mining-related seismicity on a short-term basis. A deployment of 18 geophones was conducted on the surface in and around the Bingham Canyon Mine, a large open-pit mine near Salt Lake City, Utah, USA, where we find the small seismic array can detect and locate a variety of mining-related seismic sources, even with an extremely simplified velocity model. We outline the process of creating an idealized velocity model, developing a local magnitude scale, and interpreting the observed seismicity. Of note, we analyze a sequence of mining-induced events associated with a known structure on the south pit wall. We conclude with discussion on how surface-based deployments may be used to augment, or in some cases supplant, borehole seismic networks at large open-pit mines depending on monitoring requirements and objectives.

Apr 26, 2022

By P. C. Thakur

The productivity in coal mines, measured in terns of the output per manshift depends largely on the efficiency and speed of men and materials transport between working faces and the surface. The mechanization of coal winning and material handling processes has led to a great rise in the mine productivity (1). Early applications of power in U. S. coal mines were mainly electrical. The excellent traction available with the DC motor and the ease of the distribution of the DC power have made trolley wire installations for haulage very popular. In shallow mines with very limited emissions of methane it did not constitute a major hazard but as mine depths increased and corresponding emissions of methane also increased fire and methane ignition hazards have become very serious. Conveyors have proved economic where intense mechanization of coal faces generates a large output of coal from a single face, but the fire and respirable dust hazard associated with them are no less serious. Recognizing these shortcomings, the Federal Coal Mine Health and Safety Act of 1969 laid down numerous provisions for the safe use of trolley-wire haulage and conveyors (2) which generally improve safety but in some cases complicate mining operations and have decreased productivity significantly since 1969. In course of time as coal mines become deeper and hence gassier and as the emphasis on safety increases it would be inconceivable to use trolley-wire haulage under ground as already witnessed in several other countries with deep coal mines. With rising capital investments and cost of the protection against fire and respirable dust, the use of conveyors may also have to be limited to special areas, e.g. main entries. Indeed, there are only two alternatives available, namely; (1) Degasify the coal seams prior to mining and use conventional electrical power, or (2) Develop alternate sources of power which would be safer and yet efficient and cheap.

Jan 1, 1975

By William Gleason

Since 2004, Dave Kanagy has served as the executive director and chief executive officer of SME. In that role, he has worked with 22 SME Presidents, traveling the world to represent the Society. His prestigious one-million-mile status with United Airlines is a testament to these efforts. He has been to six of seven continents while leading the Society on a journey from a struggling association in 2004 to the largest and arguably the most influential professional mining society in the world. In the following pages, some of those past SME Presidents reflect on their time with Kanagy and paint the picture of a visionary leader who was willing to make the hard decisions for the betterment of the Society while remaining open to new ideas and opportunities. One of his first accomplishments as the executive director was to streamline the SME Boad of Directors from 29 members to nine, making it much more effective. With a keen financial sense, he was able to add value while cutting excess to expand the Society in every measure. As the leader of SME, Kanagy helped facilitate much of the Society’s growth and innovation as the world’s largest mining related organization. He has a B.S. degree in industrial education from the University of Maryland, an M.S. degree in technology education from Eastern Illinois University and is a certified association executive by the American Society of Association Executives. Under his leadership, several unique programs were created or advanced, including OneMine.org, the world’s foremost online mining research library. He enhanced legacy programs and increased collaboration with international organizations. Kanagy is the recipient of prestigious awards, including the Colorado Society of Association Executives’ Professional of the Year award and the Mining and Metallurgical Society of America’s Gold Medal award.

Feb 1, 2026

By L. Sandbak

The Turquoise Ridge Joint Venture (TRJV) is located in northern central Nevada, and is situated within the Basin and Range province, near the northeast end of the Osgood Mountains (see Figure 1). The TRJV mine consists of typical Carlin type- gold mineralization characterized by low strength rock of altered limestones, siltstones, and mudstones. The weak nature of the ground facilitates the underhand cut and fill mining methods. TRJV has been working to optimize ground support and mechanize top cut drift sizes and eliminate operating hazards associated with jackleg drilling. Safety Factor analysis based on bolt strengths has allowed us to pursue larger sized top cut drifts and to evaluate bolt length sizes and spacing. Switching from jackleg sized drifts of 10?W x 10?H to a mechanized 12?H x12?W top cut drift design has the potential to decrease overbreak, provide more uniform drift design sizes and bolt patterns, and increase ore production by at least 38%.

Feb 23, 2014

By R. A. Wyman

"The froth flotation process was patented by E.L. Sulman, H.F.K. Pickard, and John Ballot in 1906 . . . . . . . . . .James M. Hyde installed the first froth flotation process in the U.S., about August 1, 1911, at the Basin Reduction Co. plant, Basin, Montana . . . . . . . . . .By 1914, 42 mining companies were operating or experimenting with the flotation process . . . . . . . . . .The period 1930 to 1960 saw the application of flotation spread to nonsulphide ores and become the key factor in the economic production of many industrial minerals". So states FROTH FLOTATION, 50th Anniversary Volume, published by AIME in 1962. It is interesting, to observe that the Mines Branch, now part of the Canadian Department of Energy, Mines and Resources, was established in 1907 through an act of Parliament entitled, "The Nines and Geology Act". In 1911, a mineral dressing group was formed and a laboratory was constructed. By 1921, an engineer was devoting full time to industrial mineral processing problems.

Jan 1, 1971

By D. J. Barratt

The application of autogenous and semi-autogenous grinding circuits in recent years has contributed toward substantial savings in capital and operating costs compared to conventional circuits, particularly for large scale copper and molybdenum operations. Such savings have been realized from the deletion of operating, maintenance, equipment purchase and substantial civil/structural costs associated with secondary-/tertiary crushing and screening, fine ore storage and conveying. In spite of the downturn in the copper- moly industry in North America, there is still an interest in autogenous and semi-autogenous grincting for copper-zinc, gold and silver ores and in the overseas market. Both single-stage and two-stage circuits are in operation. Primary circuits operate autogenously or semi-autogenously in either open or closed-circuit. Critical sizes are extracted and crushed for recycle in some cases (e.g. ABC circuit). Secondary grinding is conducted using ball mills or pebble mills.

Jan 1, 1985

By W. D. Blackburn

If there is a single key to managing a mineral extraction company, it is the control of productivity. American labor costs, in general, tend to be in the range of 10%-15% of total costs. American coal mining labor costs, however, exhibit ranges of 30%-60% of total costs. Is it any wonder that the industry finds itself at a competitive disadvantage? When labor costs take as much as sixty cents of every dollar of revenue, there is little room for profitability. The American coal mining industry must set as a long range goal the reduction of labor costs to the 10%-15% range of total costs in order to be competitive.

Jan 1, 1986

By R. Srikanth

Dust control in high production longwalls is a major problem requiring, among other things, careful attention to the design of operating practices, and ventilation schemes. Several studies have shown that the shearer is the major source of dust on a longwall face. Support movement has not been regarded as a major source of dust in U.S. longwalls; yet under certain conditions, 31 percent of the shearer operator's dust exposure can be due to support movement. Several methods have been developed for the control of shield-generated dust. Yet the need for better methods is apparent. In this paper, the amount of airborne respirable dust generated per shield move is estimated from specially designed experiments on longwall faces. A total of ten experiments were conducted in five longwall faces in four different mines. Each experiment involved one face visit and lasted three to six hours. The contribution of shield movement to the airborne respirable dust concentration immediately downwind of the shield moved, varied between 0.12 and 1. 75 mg/m3 in the five longwall faces. The mass of airborne respirable dust generated by shield movement was found to vary between 39 and 386 milligrams per shield move. The results from this study reveal that control of dust from longwall shields requires a combination of approaches involving alternative operating practices, reducing shield dust generation rate, increasing face air flow, and decreasing personnel exposure.

Jan 1, 1994

By B. K. Cantrell

A miner working in an underground coal mine with diesel equipment is exposed to a wide array of pollutants from the diesel exhaust. These include CO, CO2, NO, NO2, SO2, diesel-exhaust aerosol, and a variety of hydrocarbon compounds. A quantitative definition of the health risk resulting from these exposures remains elusive, but during the past several years, progress has been made in defining the problem. Results from epidemiological studies by Garshick, et al. (1988); animal inhalation studies by Mauderly, et al. (1986); Iwai, et al. (1986); and Brightwell, et al. (1986); and in vitro studies by Lewtas, et al. (1986), have provided sufficient data for the National Institute of Occupational Safety and Health (NIOSH) to recommend that "whole diesel exhaust be regarded as a 'potential occupational carcinogen,' as defined in the Cancer Policy of the Occupational Safety and Health Administration," NIOSH (1988). NIOSH further stated that "though the excess risk of cancer in diesel-exhaust-exposed workers has not been quantitatively estimated, it is logical to assume that reduction in exposure to diesel exhaust in the workplace would reduce the excess risk."

Jan 1, 1990

By K. Marutiram, T. Umadevi, R. Sah, K. Abhishek

Low-grade iron ore received from the West Singhbhum area of Jharkhand state in India was used to develop a beneficiation flow sheet to remove alumina (Al2O3) and silica (SiO2 ) from the ore to get iron (Fe)-rich product for steel plants. Mineral characterization showed that the main mineral constituents present in the head sample are goethite, limonite, hematite, quartz, clay and gibbsite. The head sample contained about 49.2 percent Fe, 8.79 percent alumina and 12.01 percent silica. The received iron ore sample is amenable to upgradation through beneficiation to get pellet grade concentrate. The beneficiation process was established, involving crushing, screening, jigging, spiral separation, size reduction, desliming and magnetic separation. The process showed significant enrichment in Fe values to 63.5 percent Fe in concentrate, from 49.2 percent Fe. From the developed flow sheet, it is possible to obtain pellet grade fines with 63.5 percent Fe, 2.92 percent SiO2 and 2.61 percent Al2O3 with 50.6 percent weight recovery. The overall tailing loss is 49.4 percent with 34.3 percent Fe, 21.28 percent SiO2 and 14.64 percent Al2O3

Contents

Jan 1, 1985

By B. J. Arnold

During the past three years, coal samples covering a range of coal rank, ash content, size consist, grindability, and moisture content have been tested for their flow properties using a triaxial shear tester that measures the unconfined yield strength in a compressed sample of coal. The ratio of this unconfined yield strength to the sample bulk density is part of the equation used by handling system manufacturers to calculate the critical arching or critical ratholing diameter needed to ensure that coal will flow from bunkers or bins. This ratio also serves as an index to compare the flow tested. To test the applicability of the index to predicting problems with coal flow, a series of tests were conducted at CO Inc.'s Coal Quality Development Center (CQDC) in Homer City, Pennsylvania. Tests covering ranges in size consist, moisture content, and ash content were conducted by first filling a small two-ton bin with coal and then emptying the bin at a pre-set discharge rate. The actual discharge rate from the bin under the various conditions tested was measured. Samples of the coal discharging from the bin were collected. One sample was analyzed for ash, moisture, and size consist; another sample was sent to the Iowa state University for trivial shear tests (supplying an index measurement). Actual flowability results from the bin were then compared to the measured index to determine the applicability of the handleability index in actually predicting coal flow problems. This paper describes the correlation between handleability index and bin flow and explains the next stages of the project.

Jan 1, 1992

By David L. Giles

The alkalic igneous province of Montana consists of centers of laccolithic and stock-like intrusive complexes with associated sills, dikes, and breccia pipes (e.g., Judith, Highwood, Little Belt Mts.); isolated plug-like mafic bodies (e.g., Smokey and Eagle Buttes); and clusters of kimberlitic diatremes and ultrabasic dike swarms (Missouri River Breaks). The province extends in a belt throughout central Montana from the North Absaroka Range in the south to the Sweetgrass Hills on the Canadian border. Intrusive activity ranged in age from Late Cretaceous to late Miocene, peaking at about 50 m.y, ago. Diverse types of significant epithermal gold mineralization occur at many of the laccolithic centers. This mineralization took place in large part during the waning stages of, or following, igneous activity. Large remnant travertine blankets in the region attest to comparatively recent hydrothermal activity. The quartz-pyrite-gold mineralization ranges from igneous- hosted stockworks or fracture sets (Zortman-Landusky and Neihart districts) and breccia pipes (North Moccasin Mts.) to replacement zones in flanking and upwarped Madison Group limestone (Gilt Edge and Kendall districts). The latter are mostly localized by intraformational solution breccias in the upper Madison, notably near porphyry contacts. Gold mineralization in the province was accompanied by varying amounts of silver, base metals, sulfosalts, and tellurides, with quartz, fluorite, carbonate, and barite and gangue. Gold occurs as auriferous pyrite, sylvanite, or in native form. Since the 1880's, primary gold production from numerous scattered deposits in the Judith, Moccasin, and Little Rocky Mountains, along with byproduct gold from the Neihart silver district (Little Belt Mountain), has totalled around 2 million oz. The major deposits were in the 1-2 million ton range at an average gold tenor of 0.3-0.6 oz per ton. Most of the ore was mixed oxide or carbonaceous sulfide ore and was treated either by amalgamation or by roasting-cyanidation. Current activity includes heap-leach operations on bulk- tonnage low-grade (approximately 0.03 oz per ton) ores at Zortman-Landusky, and several small-scale, experimental leach or mining operations on carbonaceous replacement ores, as in the Kendall district and Spotted Horse mine. Current exploration efforts for gold are focused not only in the old established districts, but also in and around other alkalic centers, which have been unproductive to date, such as the Crazy Mountains, Sweetgrass Hills, and Bearpaw Mountains. Target concepts in these efforts are porphyry-hosted stockwork or disseminated gold ores and Carlin-type replacement lodes in the flanking Madison or other favorable carbonate units.

Jan 1, 2013

By Elisa Comis, Jeffrey Peterson, Yama Ebrahimi

Construction of the Northeast Boundary Tunnel (NEBT), the last leg of the Anacostia River Tunnel System on DC Water’s Clean Rivers Project, started in September 2018 and was completed in April 2021. The 26-foot-bore earth pressure balance (EPB) tunnel boring machine (TBM) mined 26,737 feet at elevations between 80 to 160 feet belowground. Approximately 55% of the tunnel was cut through lower predominantly coarse-grained facies identified as the Cretaceous Patuxent Formation (undifferentiated) (PTX), and the remainder was cut through upper predominantly overconsolidated fine-grained plastic material facies identified as the Cretaceous Patapsco/Arundel Formation (P/A). Mixed face conditions were encountered in the transition from the P/A to the PTX and vice versa. This paper reviews the performance of the TBM that mined the NEBT through several unique challenges, including 8,000 feet of tunneling under the heavily developed Rhode Island Avenue corridor, major sensitive structures, cast iron water distribution mains, and other sensitive utilities.

Dec 1, 2022

By L. F. Ruppert, R. C. Milici

Coalbed methane (CBM) is currently being produced from a relatively small area in the Dunkard and Pocahontas basins, in the northern and central parts of the Appalachian Basin, respectively. In general, much of the production occurs where the coal beds are beneath 500 feet or more of overburden, where the rank of the coal is high-volatile B or greater (%Ro >0.8), and where the natural fracture system is enhanced by structural deformation. It is anticipated that near-term CBM development will continue within these areas and will expand in the Appalachian basin as technology improves and as the price of gas rises.

Jan 1, 2003

By Dairo E. Chaverra, Carlos Argumedo‑Jimenez, Oscar J. Restrepo‑Baena

This paper presents the results obtained by processing a gold and silver telluride mineral concentrate from a mine in Colombia. An acid wash, also known as acidification, was carried out, followed by oxidation with nitric acid as a pretreatment. Cyanidations of the pretreatment residues were carried out and the results were compared with results from cyanidations of base materials. The removal of carbonates in the acidification, a tellurium extraction close to 90% during the pretreatment, and a 30% improvement in the gold recovery compared to the conventional process were achieved.

Nov 8, 2023

By E. Bloomstein

The Lone Tree gold mine is located about 4S kilometers east from Winnemucca on the west flank of Lone Tree Hill in Humboldt County, Nevada. The deposit occurs at the north end of the low, rolling Havallah Hills and is about 1 kilometer south of Interstate Highway 80, in sections 11 and 14, Township 34 North, Range 42 East, Mount Diablo Base and Meridian (Fig. 1). The Lone Tree deposit is outside of any previously established mining district and all lands are owned or controlled by Santa Fe Pacific Gold or affiliated companies.

Jan 1, 1993