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By B. Weyerman

U. S. Steel's Oak Grove Mine experienced several top hinge failures on their caving shields. It was determined that all the caving shields needed to be replaced with new caving shields before more thilures occurred. The cost and amount of time needed for several scenarios of caving shield change outs were compared. This paper discusses how Oak Grove Mine decided to and did change 126 caving shields in six specially designed jig stations underground during a longwall move using their own UMWA employees.

Jan 1, 2001

By Stephen J. Brower

Located in Central Nevada, The Round Mountain Gold deposit has been continuously mined since 1977. Present proven and probable reserves are 226 Mt (250 million short tons) at 1.1 g/t (.032 oz per short ton). The current open pit mining rate of 118 Kt (130,000 short tons) per day is producing 41 Kt (45,000 short tons) per day of ore to be processed by heap leach methods. At this rate, the current reserves provide a 16 year mine life. The high mining rate and strict ore delivery requirements mandate comprehensive and realistic mine planning. The mine planning process is described in three general steps: Deposit Modeling; Mine Design; and, Production Coordination and Support.

Jan 1, 1989

By J. A. Zimmer, M. S. Hillis, D. Moredock, J. A. Organiscak, A. B. Cecala

Enclosed cabs have been used on surface mining equipment for many years to protect equipment operators from health and safety hazards. The surface mining and quarrying process is a highly mechanized process that generates large quantities of respirable dust. Due to economic factors, more older mining equipment is being used today than in years past. With this older equipment, it is common to observe deterioration of many components on the enclosed cabs, which greatly reduce their protection effectiveness. NIOSH has performed a number of different field studies, as well as a comprehensive laboratory study, evaluating various factors and parameters regarding enclosed cabs. NIOSH has recently completed a cooperative research effort to evaluate the effectiveness of a newly designed unidirectional powered precleaner, filter and pressurizer that brings clean filtered air in at the roof of the cab and extracts all recirculated air near the floor. This research effort provided another example of the enhancement in air quality that can be achieved in an enclosed cab from the implementation of an improved filtration system and by establishing positive pressurization from increased intake air volume and sealing the cab. This testing showed a significant reduction in respirable dust levels in the enclosed cab when comparing baseline versus post-testing results. Since dust levels were similar near the roof and floor of the cab during post-testing, the unidirectional flow pattern did not appear to significantly improve the performance over the conventional design in this study.

Jan 1, 2009

By Michelle Pienaar, Musa S. D. Manzi, Thabang Kgarume, Glen T. Nwaila, Raymond J. Durrheim, Abrie Oberholster, Hennie Grobler

The South African Mining, Extraction, Research, Development and Innovation (SAMERDI) strategy was launched in 2019 with the goal of modernizing the mining industry. It comprises three major research initiatives: improvement in the efficiency of extraction and health and safety in current mining operations, development of fully mechanized systems to mine narrow tabular ore bodies in hard rock, and development of extraction systems to break rock without using explosives. The crosscutting Advanced Orebody Knowledge (AOK) program seeks to develop and implement drilling and geophysical technologies that can characterize the rock mass ahead of mining and identify potentially hazardous geological features. This knowledge will be integrated with information derived from seismic monitoring. Mining methods, layouts and rock support systems will be adjusted accordingly to mitigate the risk of rockbursts. Boreholes are routinely drilled ahead of mine workings using diamond-impregnated bits. The drill core is logged to identify lithology and geological structures (especially dykes and faults that may be seismogenic), sample the ore body for grade control, and detect areas that may contain water and/or flammable gas. Methods and technology to improve the efficiency of drilling and maximize the information obtained from the drilling process, borehole core, and the borehole itself are being investigated. A range of geophysical technologies are being developed to map the rock mass from the skin of the excavation to a distance of several tens of meters. Light Detection and Ranging (LiDAR) is used to map the geometry of the excavation, including prominent joint, vein and fracture sets and the presence and performance of rock support elements and systems. Ground Penetrating Radar (GPR) is used to penetrate deeper into the rock mass and image joints, fractures bedding planes that influence the stability of the hanging and side walls. Image processing techniques known as ‘seismic attributes’ are being applied to the radargrams to improve interpretation. Electrical Resistivity Tomography (ERT) and various active and passive seismic techniques (e.g. Tunnel Seismic Profiling (TSP), ambient noise tomography) achieve even greater penetration into the rock mass. Finally, machine learning is used to improve the processing and interpretation of seismic and radar data.

Apr 26, 2022

By Loic Galisson

"Urban tunneling projects are usually extensively monitored. Most of the instruments used rely on benchmarks providing a sustainable datum throughout the life of the project. The monitoring program also is based on a predicted model of deformation induced by specific construction methods. Events can interfere with those assumptions and eventually alter the stability of these datum. In addition, the anticipated ground conditions and hence the theoretical deformation model often differ from reality. Satellite Radar Interferometry provides useful information to overcome the weakness of the hypothesis made before construction. It is also a powerful tool to ensure the continuity of the monitoring program throughout the life of the project, accurately describing the true effect of the project on the surrounding environment. This paper emphasizes the benefits and limitations of this technique for urban tunneling applications, illustrated by examples of major tunneling projects around the world. MONITORING URBAN TUNNEL PROJECTS Why Monitoring? Retrofitting existing tunnels or constructing new tunnels – including access and retrieval shafts, portals and cross passages – implies an alteration of the neighboring soil structure. Excavating, dewatering, grouting, loading tie backs, etc. artificially modifies the natural equilibrium of the pore-water pressure, of the water table level and of soil stability. In many cases, the effects are immediate: ground loss, deformation of utilities, settlements of buildings, and distortion of infrastructure are a few examples resulting from construction activity.Instrumentation and Monitoring Scope To control and mitigate the risks of damage associated with the above effects, tunnel projects usually include an instrumentation and monitoring program. Depending on the level of geotechnical, structural and environmental risk, the magnitude of this program varies. Projects with a low exposure to risk may restrain the program to conventional methods such as limited topographical surveys and intermittent manual readings of geotechnical instruments. On the other hand, iconic projects with high risk or with controversial history may implement complex and extensive instrumentation plans, involving highly technical solutions such as Automated Motorized Total Stations (AMTS – see opposite Picture 1), Multi-Point Borehole Extensometers (MPBX), In-Place Inclinometers (IPI) and a wide series of fully automated geotechnical, structural and environmental sensors. In this case, all the devices are usually connected to field data loggers collecting raw data around the clock at frequencies ranging from days to seconds, depending on the sensors."

Jan 1, 2016

The need for an integrated approach to optimization of unit operations in both the pit and the mill has long been recognized, but the complexity and nature of the overall problem has up to now resisted solution. This paper reports on a modeling methodology which couples symbolic and numeric computing to unify operations in both the pit and mill. The ultimate goal of this work is to optimize all operations that are influenced by blasting. Blasting plays a key role in all facets of operations. Obviously, drilling and blasting costs are determined by blast design, but the down-stream costs that are closely related to blasting results are often treated as separate functions: loading, hauling, cleanup, and crushing and grinding are all heavily influenced. Diggablilty and bucket fill factor are a function of fragmentation, the condition of the floor and uniformity in the shape of the muck pile. Likewise, cycle times and loading delays partially determine haul cycles, while fragmentation distribution and size determines the efficiency of truck loading. Removal and breakage of oversize causes loading delays and increases cleanup costs. The influence of blasting doesn't stop at the crusher. Mill productivity, power consumption, and maintenance are a function of the feed. Even at the SAG mill a reduction of a critical particle size during blasting can increase throughput. Thus, a bottle-neck for production far removed from unit operations in the pit can be alleviated by a modification in blast design. The question is: how do we optimize blasting with respect not only to itself but to al\ related mining and milling operations? For that matter, how do we even model blasting so that we can control the results of a blast?

Jan 1, 1991

By Harry Perry

The Bureau of Mines is glad to have this opportunity to discuss its present Coal Research Program and its significance to the industry with a group which has for many years been representative of the coal producing community. We believe we have a dynamic program that will help our vast coal resources to find their proper place in the U. S, economy. The present coal research activities of the Bureau are conducted in three organizational subdivisions: Minerals Research, Mineral Resource Development, and Health and Safety. All investigations are carried out in Bureau research facilities located in different sections of the country, Since its creation by the Organic Act of 1910 and subsequent amendments, the Bureau has worked closely with the coal industry--first by providing assistance in mine safety for anthracite and bituminous coal mining, and since that time, in providing information on conservation, safety, mining, preparation, and utilization.

Jan 1, 1966

By Richard H. Johnson

White Pine Copper Company began operating a plant designed to recover copper matte particles from its discarded reverberatory furnace slags in April, 1972. Seasonal operation, generally the months of April through November, continued through October, 1974, shutting down due to feed exhaustion. White Pine reverberatory furnace slags contained economically recoverable amounts of copper for a variety of reasons. Among them: 1. White Pine concentrates yield extremely high matte grades (65+% Cu) and viscous slags. The viscous slags hinder matte settling causing matte "prill" entrapment in the slag 2. White Pine's total refined copper output is accomplished through fire refining requiring special techniques for impurity removal, especially small amounts of nickel introduced from purchased pyrite and chalcopyrite fluxes. These special techniques result in high-copper slags, refractory to smelting, being reintroduced into the reverberatory furnace. 3. Furnace bottom build-ups resulting in mechanical matte entrapment through the formation of "dams" hindering matte flow. 4. Occasional concentrate fluxing and furnace atmosphere control problems.

Jan 1, 1975

By J. D. Miller

The sedimentary western phosphate deposits of Idaho, Montana, Utah, and Wyoming tend to be calcareous and generally carry a significant amount of dolomite along with collophanite. In some cases, such as the Smokey Canyon Mine, Afton, Wyoming, the ore will also contain mudstone, and in this case the aluminosilicate minerals (clay, feldspar, etc.) together with some dolomite are floated from the collophanite in column flotation cells with an amine in order to meet product specifications (31 % P205) (Service et al.). In other cases, such as the SF Phosphates Limited Mine, Vernal, Utah, the ore is treated by traditional fatty acid flotation of the collophanite with mechanical flotation cells (Weber, 1986). Preliminary tests have now been conducted to evaluate air-sparged hydrocyclone (ASH) technology for the flotation of western phosphate ore. For this preliminary study, samples were taken from the hydrosizer overflow stream (18-21 % P205) at the SF Phosphates Limited Plant in Vernal, Utah for scavenger flotation testing with the 2-inch ASH system in laboratories at the University of Utah. Selected design and operating variables are being studied, and the initial results show that satisfactory separations can be achieved by high-capacity ASH flotation at appropriate operating conditions. For example, with single-stage ASH flotation 80% recovery can be obtained with a scavenger concentrate grade of about 26% P2O5. These results are comparable to, or better than, those obtained at SF plant operations with conventional flotation cells and suggest that ASH flotation technology can be used to good advantage in the phosphate industry. Of course, research should be continued to consider other process streams, optimize the separation efficiency, and evaluate larger diameter ASH units.

Jan 1, 1993

Since 1955 Gaspe Mines has produced 144 million tonnes of ore, averaging 0.87% Cu, mined from two open pits and underground workings. In 1994, four exploration drill holes discovered a buried porphyry/skarn Cu-Mo deposit at depths of between 1000 m and 1700 m below the top of Porphyry Mountain. The mineralization and alteration associated with the Porphyry mountain quartz monzonite does not outcrop. A total of 19,500 m of drilling in 12 drill holes has outlined 200 million tonnes grading 0.73% Cu and 0.08% Mo. Mineralization occurs as veins and disseminations of chalcopyrite and molybdenite. Drilling and feasibility studies continue.

Jan 1, 1998

By Gerald V. Jergensen, Edward J. Samuel

Slurry system are the principal method for storage and transportation of solids within and between concentration operations In a mineral processing plant. A slurry 1s a mixture of solid particles In water, or a chemical solution, that behaves like a liquid. The design of slurry transportation systems is generally analagous to pumping and piping water, but with a few notable exceptions: • The interaction of particle on particle affects slurry transport. • Particles often interact with the fluid, particularly when chemicals have been added to the system. • Particles have a frustrating tendency to settle from the slurry suspension, especially into locations not considered In the design. • Solids have an affinity for wetted surf aces and tend to wear them away. Slurry transportation systems Include a number of separate components, each requiring special design considerations. A systematic evaluation of each component of a slurry transfer system will help overlooking the small details that could cause operational headaches. Most slurry transport systems include: • A receiving sump or tank that provides for mixing and/or momentary storage of slurry. • A driving force.. by a pump, atmospheric pressure or gravity. • A suitable conduit for transportation.. pipes or launders. • A delivery objective.. another sump or process vessel, or distribution system to several process points. • A control strategy and design to regulate the transfer operation. The design of the slurry transportation system normally evolves through the following steps: • Finalizing the process flowsheet and establishing the weights and volumes to be handled. • Identifying and characterizing the various process fluids and slurries. • Defining critical and minimum transport velocities of fluids. • Selecting a pipe diameter (or dimensions and gradient) and

Jan 1, 1986

By T. S. McGahey

The southeastern region of the United States has long been a major market area for coarse and medium particle size natural ground calcium carbonate fillers. The primary market for calcium carbonate in the southeast traditionally has been as fillers in building materials such as carpeting, joint cement and roof shingles. In these applications the economic value of the calcium carbonate in the final product is weighted more toward lessening the cost of the final product, as opposed to contributing any desirable physical characteristics. For example, in carpet backing applications the calcium carbonate filler does little more from a physical standpoint than add weight and body to the backing adhesive. The important factor in the use of calcium carbonate in carpet backing is that it can be used at high loading levels to replace the more expensive latex binder, thus lessening the cost of the final product. It is estimated that calcium carbonate producers in the southeast sell in excess of 200,000 tons (181,436,000 kg) annually for use in latex compounds for carpet backing applications.

Jan 1, 1986

By Donald E. Steif

The Tower Mill is a vertical stirred mill using steel balls or pebble grinding media. This device is designed for fine grinding at significant power savings when compared to conventional tumbling mills. This paper describes the machine, its operation, application, and performance for wet grinding.

Jan 1, 1984

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

By Haydn H. Murray

This paper presents the results of test work performed with a Pacific Electric Motors (PEM) high intensity magnetic separator (20 kilogauss) , a unit capable of separating weakly, as well as strongly, magnetic minerals in the particle size range of sands to clays. Tests were performed on some 40 industrial minerals. With some minerals excellent separations were attained and with others intermediate and poor separations were accomplished. This study is a preliminary survey and many of the intermediate and poor results can be improved as separation problems are worked out with additional test work. It is demonstrated that with a number of industrial minerals high intensity magnetic separation is a viable beneficiation technique that is economic ally feasible.

Jan 1, 1976

By Nick Tessitore, Ryan Marsters, Alex Warren, Dylan Fawaz

The West Gates Deicing Industrial Waste Pond Expansion project at Denver International Airport seeks to expand utilities to accommodate additional terminal gates. The project includes six tunnel crossings beneath taxiways and runways with lengths ranging from 239 to 2,025 linear feet. Excavation methods include shielded tunnel boring machines and steerable auger boring. Designed initial support includes liner plate, steel ribs and lagging, steel casing, and Fiberglass Reinforced Pipe and ranges in size from 24" to 132". This paper will discuss challenges associated with the overall layout and design of the project, including contingencies to protect critical infrastructure. In addition, a construction update is provided.

Jun 23, 2024

Peru has become an established mining country. The industry and industry-related businesses account for a significant amount of the country´s revenue, on state and local levels. But like other countries with thriving mining industries, Peru has seen its mining industry revenues fall off in recent years due to a lackluster global economy. And the mining industry in Peru must also deal with increasing concerns about mining?s environmental impacts, local community and other social issues, as well as a regulatory environment that has placed more restrictions on what miners can do. That said, the Peruvian government is beginning to realize how important mining and natural resource development is to building the nation?s economy, improving its infrastructure and lifting its population out of poverty. The government support was evident during the Perumin 2013 mining convention, held in September in Arequipa. In addition to Peru?s President Ollanta Humala speaking at the closing ceremony, the country?s ministers of Energy and Mines, and Economy and Finance participated in the event, as well as numerous other federal and state authorities. Perumin is put on by the Instituto de Ingenieros de Minas del Peru (IIMP, or Peruvian Institute of Mine Engineers). The 31st edition of the convention, billed as the ?world?s largest mining convention? by the IIMP, this event was led by Abraham Chahuan CEO of Antamina and Romulo Mucho (SME member) as president of IIMP, attracted about 118,000 participants from more than 48 countries. This was more than the anticipated 75,000 attendance and well past the 51,000 people who attended the 2011 convention. The last edition of PERUMIN was led by the CEO of Compañía Minera Antamina, Abraham Chahuan and Rómulo Mucho (SME member) and representative of the IIMP. The event attracted more than 1,000 journalists from all over the world, the IIMP said. A total of 2,213 booths from equipment and machinery supplying companies from the five continents were present at the Mining Technology Exhibition (Extemin), including companies from the United States, Canada, China, South Africa, Germany, Australia, Brazil and Chile, among others. The convention has grown so large in recent years, that the IIMP shifted its location from Tecsup vocational school in Arequipa to the Cerro Juli Convention Center. The venue is 116 percent larger than Tecsup, the IIMP reported, covering about 20 ha (40 acres). It was reported by Latinomineria magazine that about 10 million Peruvian soles were invested in the new venue to create a world-class events center. It was also estimated that the event generated more than 234 million soles to Arequipa?s economy.

Feb 1, 2014

By Emily Wortman-Wunder

While the mood at the 2013 annual joint meeting between the Pittsburgh Coal Mining Institute of America (127th Annual Meeting) and SME Pittsburgh Section (68th Annual Off-the-Record Meeting) in Canonsburg, PA was subdued following a rocky year in the coal industry, attendance was down only slightly, to 300, and overall, the meeting?s focus was optimistic about the future of coal. The conference began by addressing one of the central challenges of coal mining head-on with a keynote address on the status of safety in the mining industry. Noting that two more U.S. miners had died in 2013 than by the same date in 2012, the National Mining Association?s (NMA) Senior Vice President of Regulatory Affairs Bruce Watzman made a plea for a new approach to safety. He described the NMA CORESafety initiative, a program that promotes proactive safety measures versus a compliance-driven model. CORESafety, described in more detail on pp. 29 of this issue, focuses on developing successful ways to change company cultures of safety and behavior. Other industries that have adopted this approach have seen dramatic drops in fatalities, including the Australian mining industry, which has seen its annual fatality rate drop to nearly zero even while the number of people employed in the industry has soared. The rest of the morning?s sessions explored what is arguably the industry?s biggest challenge right now ? maintaining the social license to operate.

Jan 1, 2014

By V. M. Lepetic

Large tonnages of copper and molybdenum sulfide ore are treated by flotation. Substantial savings could be realized, particularly in high-capacity concentrators, by use of a simplified flotation technique involving lower reagent consumption. Chalcopyrite and molybdenite from some deposits can be floated by use of only a frother as a single flotation reagent; acceptable concentrate grade and recovery can be obtained. Separation of molybdenite from copper sulfides may become simpler and less costly. The genesis of the ore and the ions present in the flotation pulp liquid phase appear to be the major success-determining factors.

Jan 1, 1972

By M. L. Mellish

In 1989, for the third consecutive year, both the production and consumption of coal in the United States reached record levels. Domestic coal consumption totaled 806.5 Mt (889 million st) in 1989, a 5.4 Mt (6 million st) increase from the year before (Table 1). US coal exporters also had a banner year. For the first time since 1982, exports ex¬ceeded 91 Mt (100 million st). US coal production in 1989 rose by a surprising 27.3 Mt (30 million st), reaching 889 Mt (980 million st) for the year. To a certain extent, the sizable difference between production and demand growth was due to smaller consumer stock withdrawals. Coal consumers withdrew only 12.7 Mt (14 million st) of coal from their stocks in 1989, com¬pared to 22.7 Mt (25 million st) in 1988. Despite strengthening coal consumption, exports, and production, coal prices to all domestic sectors declined slightly during the year. That essentially continued the trend of the past several years. On the labor front, the United Mine Workers of America struck the Pittston Coal Group in 1989. It was a bitter work stoppage that was not settled until February of 1990. This was the first major coal strike since 1985. The strike also precipitated a series of wildcat outages by UMWA members in June and July. At their peak, more than 40,000 UMWA members participated in the wildcat strikes. Except at Pittston, however, most miners were back to work by August. It is estimated that perhaps 4.5 to 9.1 Mt (5 to 10 million st) of coal production was lost due to the Pittston and associated wildcat strikes. However, some of this production may have been recouped by other coal companies not affected by the wildcat strikes, and by the affected companies after the strikes ended.

Jan 1, 1990