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By Ernest M. Spokes

Starting in 1980, a committee of the National Research Council studied the question of why some underground coal mines are safer than others and what could be done to improve the ones with poorer performance. The results indicated that safety is improved by management commitment to safety, by cooperation between labor and management on safety matters, and by quality training of employees and managers. Younger mines have higher accident frequencies, but are less likely to be killed or permanently disabled by a lost-time accident. Methods for improving safety performance are proposed.

Jan 1, 1983

By Dennis K. Mortensen

The warm southwestern desert of Arizona is an ideal location for ASARCO's new Sacaton Unit. The climate of this arid region played a major role in the design considerations of the Unit's crushing and concentrating facilities. Low yearly rainfall and relatively high yearly temperatures are a combination that was taken advantage of when designing the surface facilities. The plantsite, located due west of the mine pit, is in an area originally covered with sparse desert vegetation, underlain to an average depth of 125 feet by desert alluvium. The entire plantsite area slopes gently to the southwest at approximately 1%. Ground conditions at the plantsite area were not acceptable for construction due to the collapsability of the wetted soil when under loaded conditions, Overburden from the pit area was used to form the foundation for the entire plantsite. This waste material, entirely devoid of rock, was placed and compacted to an elevation approximately 20 feet above the desert floor. Elevating the plantsite by filling with waste material not only provided an adequate construction foundation but also eliminated the possibility of flooding from run-off in the surrounding desert areas.

Jan 1, 1974

By Andrew J. Petruska, Rik Banerjee

This study explores implementing a machine learningbased system to generate a 3D surface repre- sentation of the roof and support straps in the mine. Event cameras have been chosen for their performance in high-dynamic-range lighting conditions and for their low latency. To enable automated drilling and bolting, 3D vision using eventbased cameras has been developed. A ground-truth set is created using two, time-synced event cameras and a LiDAR camera. These sensors are used to construct a ground-truth dataset of corresponding event- camera images and surface maps from the LiDAR. The network is tested with stereopairs of event images and produces a depth image with ±5 mm RMS error on average across 1000 test images.

Feb 1, 2024

By Brian Ulrich

The majority of individuals involved in the mining industry can appreciate and under-stand that mining is an activity that is necessary to satisfy the very basic needs of society, and to assist in accommodating our ever-changing world. As the expression goes, ?if it can?t be grown, it has to be mined.? And at this point in time, society has granted the mining industry the right to go about the business of mining, with the general anticipation that the work will be carried out without causing undue harm to the environment or populations in and around the mining operation. The term ?sustainable development? is gaining momentum as a popular concept, and indeed it has become something of a catch-all phrase, but it is important that the idea behind the term is not cast aside as a nonsense buzz word, as it simply is an indication that development (e.g. mining) can be satisfactorily carried out with an eye toward stewardship of the environment and society. On Feb. 19, 2010, a round-table discussion (Roundtable 2010) on ?Strides Toward Sustainability in Mining? was hosted by Knight Piésold and Co. (Knight Piésold) at the Red Lion Inn and Casino in Elko, NV. Knight Piésold had local representatives (Bryan Ulrich and Steve Boyce), as well as representatives from other office locations (Cynthia Parnow and Rick Damiani from Denver, CO, and Rick Frechette from Tucson, AZ) to help facilitate the discussion. The meeting played host to 30 attendees from five states. Attendees included personnel from nine mining properties and various corporate offices. The majority of participants were people who are directly involved with environmental work on a day-to-day basis. Others were project managers whose jobs involve some level of environmental focus.

Jan 1, 2010

By A. K. Snelgrove

At a time when water resource planning is proceeding on a continental scale, such as the proposed $100 billion North American Water and Power Alliance, which would redistribute water among three nations, including seven provinces of Canada, 35 of the United States, and three States of Mexico, the selection of a single river basin for study may seem to require an apologia. None is offered because of ( 1) the magnitude of the Indus , itself a part of the great Indo-Gangetic Plain drainage system, with Himalayan sources, upon which the thickly populated northern sub-continent of Indo-Pakistan depends for agriculture and hydroelectic power; (2) the extraordinary problems created by dismemberment of the world?s largest irrigation system through legal beheading of the Eastern Waters under the Indus Waters Treaty of 1960; and (3) the herculean effort to contain the twin encroachments of waterlogging and salinization in a basin which faces a shortage of fresh water. The British irrigation system of barrages and canals on the Indus was a venture admirable in conception. Unfortunately, it is now a legacy burdened with unwanted consequences, due to interference with the hydrological regimen, particularly the rise of water table occasioned by leakage.

Jan 1, 1967

By Paul Wellman

The energy problem of the U. S; was emphasized by the oil embargo of late 1973 and early 1974 and it seemed for a time that the Federal Government, under pressure from the general public, might take some corrective action. However, this was not the case. With the gasoline lines gone and an apparent plentiful supply of petroleum products, public concern quickly dissipated., This country is more vulnerable to an oil embargo today than we were in 1973-1974 and this fact should be of concern to all our people. Since 1968, we have used oil and natural gas at a much more rapid rate than we have been able to find new domestic sources; thus, there is an increasing gap between domestic production and consumption and we have filled the gap with ever increasing oil' imports. These imports have increased at an alarming rate in the recent past, some 58 percent in 1976 compared with 1975. Imports are nearing 8 million barrels per day. Then, by applying some simple arithmetic, at $12 per barrel, the resulting trade deficit is $96 million per day or $35 billion per year. Obviously, this cannot be tolerated by our economy over a long period of time. Historically, we have shifted from one fuel to another as is shown in this slide. In 1850 about 90 percent of our fuel requirements came from direct combustion of wood, by 1900 we shifted to coal for 70 percent of our fuel, and now about 78 percent of fuel requirements comes from oil and natural gas. The difference is that the previous shifts were voluntary and the one facing us now is of necessity.

Jan 1, 1977

By B. A. Ashley

Rosebud Mining Co. (RMC) is based in Kittanning, PA. As of October 2013, it operated 24 active underground mines in Pennsylvania and Ohio. RMC?s Tracy Lynne Mine is located approximately 5 km (3 miles) east of Apollo, PA, (approximately 48 km or 30 miles northeast of Pittsburgh, PA) and mines the Lower Kittanning coal seam. The coal seam averages approximately 1.1 m (45 in.) thick and is of steam coal market quality. The mine is a single unit operation. Coal is mined using a continuous mining machine and is transported from the face to the conveyor belt using a continuous haulage system. Typical ventilation in the mine consists of an exhausting fan that draws air through isolated intake, belt and return air courses (Fig. 1).

By V. T. McLemore

New Mexico Bureau of Geology and Mineral Resources (NMBGMR) has been collecting data on uranium mining districts, mines and mills since it was created in 1927 and has converted years of historical data into a relational database that can be imported in ArcMap. The database includes information on mining districts, mines, mills and geochemistry, as well as photographs and bibliographic resources. The available data includes location, production, reserves, geologic, geochemical, resource potential and other data. The National Uranium Resource Evaluation (NURE) stream-sediment data provides geochemical analyses for >27,000 samples collected in New Mexico during the 1970s. The NURE hydrogeochemical data provides analyses of water samples. ArcMap includes the location of individual ore bodies as polygons and incorporates the mines and NURE data as individual site locations. The purposes of these databases are to provide computerized data that will aid in identifying and evaluating resource potential, resource development and management, production and possible environmental concerns, such as physical hazards (i.e., hazardous mine openings), indoor radon, regional exposure to radiation from the mines, background geochemical data and point sources of possible pollution in areas of known mineral deposits.

Jan 1, 2010

By H. Verakis, M. A. Hockenberry, A. C. Smith, J. H. Rowland III

Four different types of fire suppression systems were evaluated in large-scale fire experiments to study the effect of air velocity on their effectiveness in extinguishing conveyor belt fires. The four different types of suppression system were water sprinkler, deluge-type water spray and two different dry chemical fire suppression systems. The large-scale fire tests were conducted with 1.8-m- (72-in.)-wide fire-resistant rubber belt that met the Mine Safety and Health Administration flame resistant requirement specified in Title 30, Code of Federal Regulations, Part 18, section 18.65 (also known as the 2G Flame Test). Each fire suppression system was tested at air velocities of 152 - 168 m (500–550 ft) per minute (mpm) and 411 - 457 mpm (1,350 - 1,500 fpm). Two tests were conducted at both air velocities for each fire suppression system. Both of the water-based fire suppression systems were able to suppress the fire to the point that a miner could extinguish it with a fire extinguisher. However, the amount of water needed to suppress the fire to the point where a miner could walk up to and extinguish any smoldering belting was greater than the current MSHA regulations required. MSHA regulations only require 10 minutes of water supply for a suppression system. In the test setup, neither of these systems would have suppressed the fire had the water been turned off to the system after 10 minutes. The dry chemical suppression systems produced mixed results. Dry chemical suppression system A did not suppress the conveyor belt fire at either air velocity. Dry chemical system B suppressed the fire at 152 mpm (500 fpm) air velocity, but produced mixed results at the higher air velocity. Details are presented on the large-scale fire test setup, arrangement of the fire suppression systems and conclusions regarding the effect of air velocity on fire suppression system design and performance.

Jan 1, 2010

By Klaus Schönert

In the analysis of comminution processes, it is necessary to have a detailed knowledge of such sub-processes as: (i) The transportation of the particles to the zone where they are stressed, (ii) The stressing of the particles to a level high enough for breakage, (iii) The removal of the fragments that are smaller than the limit size from the grinding zone, and (iv) The prevention of agglomeration of the fine fragments. The breakage phenomena of particles is the most difficult sub-process to understand. It can be understood only by applying the principles of fracture physics to obtain information about the stress-strain field in particles which are loaded either by compression or by impact, and by using this theoretical knowledge to interpret experimental results obtained from single particle crushing studies. It is not only of academic interest to know how a particle breaks, but also it is important for practical applications because it provides a basis for evaluating both the direction and limitation for any potential comminution improvement.

Jan 1, 1971

By D. Berberick

Hecla?s Lucky Friday Mine is a deep, underground producer of silver, lead and zinc in the Coeur d?Alene mining district of northern Idaho. Main access into, and production from, the mine is via the Silver Shaft, a 5.5-m (18-ft) diameter, concrete lined shaft sunk by J.S. Redpath to an original depth of 1,890 m (6,200 ft) in the early 1980s. The shaft is divided into four compartments (Fig. 1), with sets made of 225 mm x 175 mm (9 in. x 7 in.) hollow structural section (HSS) steel buntons and 150-mm x 150-mm (6-in. x 6-in.) HSS dividers spaced every 4.5 m (15 ft) down the length of the shaft. Two skip compartments on the east side of the shaft are equipped with 125-mm x 150-mm (5-in. x 6-in.) HSS steel guides and 9-t (10-st) skips with three deck trailer cages for men and materials. The west side of the shaft is divided into a manway, and a fourth compartment that was originally designed for a service cage. Shaft services consist of a 250-mm (10-in.) a compressed air line and 150-mm (6-in.) sandfill line along the south side of the shaft, and 250-mm (10-in.) discharge (gray) water and 150 mm (6 in.) fresh water lines on the north wall. The mine?s primary 13.8 kV power lines, as well as communication lines are located on the west wall of the shaft. The production hoist is a 3.7-m (12-ft) diameter, double drum, double clutch, 2,238 kW (3,000 hp), direct current unit equipped, at the time, with thyristor drives. The 30-year-old drives would prove to be problematic during the rehabilitation project, leading to an upgrade to modern ABB drives later in the project, after the shaft rehabilitation was complete. The shaft had been subjected to the typical wear and tear of 30 years of operation, including intermittent sandfill and muck spills, and, in the lower areas, some corrosion. During those 30 years, the west compartment, originally designed for the service cage, could only be accessed from a work deck on top of the skips or from the manway.

By William Detty

An architect representing the Atlanta office of the Brick Institute of America periodically presents a slide lecture to interested groups entitled "The First 10,000 Years of Brick". The title signifies the fact that brick, man's oldest manufactured building material, has been around for quite some time and will continue to be utilized by architects and builders in the foreseeable future. This is not to say that the brick industry can rest on its laurels and ignore the competition presented by newer more innovative products. The industry will have to be equally inovative and market oriented in order to maintain its market share of the predicted construction boom between now and the year 2000. The implication is made, however, that brick can be produced under rudimentary conditions and that the desire to use the product has been long standing. In addition, history has sham that there has been plentiful clay available to produce the product. This paper is an attempt to assess the climate in which the brick industry will operate during the next 26 years. An analysis of regulatory conditions affecting the manufacture of the product will be followed by an assessment of the materials environment in which the industry will be operating. These factors are then reconciled with a projected demand for the product to determine the ability of the industry to satisfy future demand for brick. From a mineral point of view this paper will address itself generally to the availability of and demand for clay. However, other than a brief overview of the uses of other specific types of clay, it will concentrate on the clays utilized in the production of structural clay products, specifically brick.

Jan 1, 1974

The most complete mining show ever held in the United States and the largest exposition of its kind to be held anywhere in the world in 1988. That's how the American Mining Congress is billing its "MINExpo International '88," to be held April 24-28 at Chicago's McCormick Place, the largest exposition facility in the country. MINExpo International '88 will combine for the first time two previously separate AMC-sponsored shows - the International Coal Show and the International Mining Show. Starting with the 1988 show, MINExpo International will be held every four years. The next show, in 1992, will be held in Las Vegas. The MINExpo in Chicago will feature more than 500 mining equipment and services exhibits covering 3 hm2 (320,000 sq ft) of exhibit space. Exhibitors will display products ranging from small safety devices to large earth-moving equipment. MINExpo is one of the few trade shows selected by the US Department of Commerce for its Foreign Buyer Program. Commerce is working with US embassies around the world to publicize MINExpo and to form delegations of visitors from many countries. Overseas visitors to the show will be assisted at an on-site International Business Center. It will provide currency exchange, translation, and other services to foreign buyers. Registrants at MINExpo will also be able to attend their choice of 27 morning-only program sessions. At these sessions, international mining experts from industry, government, and academe will analyze technical, strategic, and policy matters and discuss the outlook for the industry. "Toward the 21st Century" is the theme of this year's program. The technical workshops and managerial seminars are designed to assist mining executives, engineers, and geologists as well as mine superintendents, managers, and foremen in handling their responsibilities. Based on previous attendance at AMC international mining shows, the association says that more than 25,000 persons are expected to attend the Chicago show. It is expected that approximately 15% of the attendees will be from foreign countries. The Soviet Union will be among those exhibiting at MINExpo. The Russians have leased more than 2.8 dame (3000 sq ft) of space to display their mining machinery and equipment. It is the first time that the Russians have joined in an exhibition of mining equipment in the US. The two largest manufacturers of mining equipment in the Soviet Union, Setmash and Avtoexport, will put on display in Chicago a variety of Russian-made equipment. It will range from 100 t (110 st) heavy-duty dump trucks and diesel engines to drilling, hoisting, and conveying equipment. In addition to some 400 US exhibitors of mining equipment and services at MINExpo, nearly 100 companies will be present from other major mining nations such as Australia, Canada, Great Britain, Japan, the Netherlands, and West Germany. And, for the first time, a Chinese manufacturer will take part in the AMC show, participating with its US marketing partner.

Jan 3, 1988

By L. H. E. Weyher

Minerals beneficiation commonly requires initial crushing and grinding so that the mineral phase we seek to concentrate is adequately liberated to obtain a product of specified grade at optimum recovery. To some degree this also is true for coal preparation. In the comminution process we liberate not only the product but also the tailings phase. The true objective is, therefor, to eliminate from the comminution circuit whatever particulate matter has reached specified liberation, regardless of whether the particle is product or tailings material. Overgrinding either of the two phases ties up mill capacity and usually also burdens the downstream processing steps by increasing costs or decreasing recovery, or both. In view of this situation, one would expect concentration steps to be commonly incorporated into the cominution circuit. The reasons this is not done may vary, but probably include the desire to utilize large scale unit operations, e.g., large mills, in conjunction with very simple processes. Hydrocyclones have satisfied this desire but may not always be employed for the right reasons. Hydrocyclones are indeed simple. They also are rugged and forgiving. Unfortunately, these virtues are frequently misused. The direct results are inefficient classification and overgrinding. The indirect results are added costs through recovery losses, unnecessary recirculation, and so on,

Jan 1, 1985

By James T. Tanner

Mica is a generic term that applies to a group of complex aluminosilicate minerals that have a sheet or plate-like structure and with different chemical compositions and physical properties. All micas form flat six-sided monoclinic crystals with remarkable cleavage parallel to the direction of the large surfaces, which permits them to be split into optically flat films; as thin as 1µm in thickness in some cases (Rajgarhia, 1987). Some micas are more easily split than others. For example, muscovite mica found in pegmatites is more easily split into thin films than is phlogopite. Mica found in mica schist is not as easily delaminated as mica found in weathered pegmatites. According to Dawson (1 949), the commercially important mica minerals are: Muscovite-potassium mica (colorless to pale green and ruby) Biotite-magnesium-iron mica (dark brown to black) Phlogopite-magnesium mica (pale yellow to dark brown) Vermiculite-hydrated biotite or magnesium-iron-mica (bronze yellow flakes) Lepidolite-potassium-lithium mica (pale lilac to deep purple) Some micas of less importance are: Zinnwaldite-lithium-iron mica (gray to smoky brown) Roscoelite-vanadium-potassium-magnesium mica (various shades of green and brown) Mica, principally muscovite, is widely used for industrial applications because of its exceptional physical, chemical, electrical, thermal, and mechanical properties (Table 1). Phlogopite and vermiculite follow muscovite in importance. Biotite finds very little commercial application at the present time. Commercially, mica is used in a number of forms. These forms and their description follow: Sheet mica refers to books of mica either mined from hard rock (pegmatites) or from loosely consolidated clayey material formed from the weathering of pegmatites and alaskites. These books can be readily split into thin film or splittings with specific thicknesses ranging from 0.0031 to 0.10 mm (Davis, 1985). Quality sheet mica is graded into 10 quality classifications (Tables 2 and 3). Books of mica that are flawed with excess inclusions, cracks, or folds (A mica) are called scrap mica and are either ground into commercial products by a dry or wet process. Built-up mica was developed in 1894 as a result of the cost and scarcity of sheet mica, and because many satisfactory electrical parts could be made from it (Preston, 1971). This type mica is formed by layering pieces of mica splittings upon one another and binding them together with inorganic or organic binders. These sheets are then pressed together under high temperature. Mica for this process is produced from pieces of sheet mica too small to be punched into electrical parts (Davis, 1985). Reconstituted mica is mica paper produced by forming a mat of very thin delaminated flakes of scrap mica. This mat is usually impregnated with an organic binder, but is also available unimpregnated. It is dried at 110°C. The mica for this process is either produced from the trimmings of a sheet mica operation or from blocks of A type mica (Davis, 1985, Chapman, 1983). Ground mica constitutes by far the largest use of mica, both quantitatively and application wise. It is produced by grinding and sizing scrap mica (also mica concentrate) obtained from five sources, 1) trimming from sheet mica, 2) A type mica blocks, 3) as a byproduct of spodumene and feldspar mining, 4) weathered pegmatites and alaskites, and 5) metamorphic schists. Synthetic mica is produced by crystal growth in a slowly cooled melt of accurately proportioned chemical oxides. Extended cooling times at a specific viscosity result in larger crystals. Many different micas have been formed by this process; however, fluorophlogopite is the most common.

Jan 1, 1994

By John Hanna

Over the years the coal industry in Alabama has generated about 150 million tons of fine waste coal, increasing at a rate of 2 million tons/year, during mining and cleaning operations. Reclamation of the fine-size wastes containing 20-60% by weight clean coal provides, free of charge, mined and crushed feedstocks for coal recovery and eliminates a major source of acid water pollution. Tests were made on the impounded wastes and current plant discharges to recover the coal fraction by sizing, gravity and flotation techniques. Gravity separation of the plus 100 mesh material produced commercial grade coal averaging 8.2% ash, 0.8% sulfur and 13,350 Btu/lb. However, the coal recovery was relatively low at 50-65%. Froth flotation using mechanical and froth column methods gave similar coal products at much higher coal recovery of 87-93%. The coal produced analyzed 10% ash and 1.1% sulfur.

Jan 1, 1991

By John B. Goddard

Crystallization of ammonium paratungstate (APT) is frequently the last effective purification step in producing high-purity tungsten. However, crystallizer mother liquors are often several times higher in tungsten than predicted by the solubility of APT. The formation of heteropoly anions, particularly those containing phosphorus and silicon, is largely responsible. Solubility of tungsten in APT mother liquor can be linearly correlated with the concentration of these and other impurities. The problem can be overcome by direct treatment of the crystallizer feed solution with alum. By appropriate treatment, the aluminum hydroxide flocculates and is easily filtered, resulting in a purified low-aluminum crystallizer feed from which high APT yields can be attained.

Jan 1, 1984

By D. W. Mitchell

Planning today for what hopefully will never happen is one of the surest ways to decrease the chance of it happening. As Napoleon proved and Ian Mitroff wrote, "The heat and stress of battle is the worst time to make decisions of strategic importance." Mitroff also wrote, "The value of a plan is not that it will ever perfectly match reality, but going through the process of planning speeds the process of recovery. It allows the organization to emotionally work through the worst before it actually happens." This paper concentrates on things miners must consider; on the need for plans to be like a belt conveyor strong enough to carry the load, flexible enough to stretch a little; on the criticality of throwing away fax machines and telephones, and having certain officials at the scene rather than back in head-quarters; on the training of fire brigades and mine-rescue teams; on having company-controlled chromatographs; on having people who can look at trends rather than numbers. Some of the things in this paper might anger some readers; for that, I can only ask them to consider first the problem not their position.

Jan 1, 1993

Water and wind erosion of toxic zinc and lead smelter waste is one of the most urgent environmental problems to be solved in the Silesia region of Poland. Over 87 x 106 Mg of various mining wastes were disposed of in uncontrolled piles leading to soil, water, and air pollution in highly populated areas. Welz and Doerschel process Pb/Zn smelter wastes were stabilized in the summer of 1994 by application of heavy loads of CaCO3 (30 Mg/ha), CaO (1.5 -15 Mg/ha), and municipal biosolids (150 -300 Mg/ha), followed by seeding with a mixture of acid-and salt-tolerant grass species selected in a pot experiment. Vegetation was successfully established on 85% of the Welz material demonstration plot area (0.5 ha), even though it was initially high in water-soluble Zn, Pb, and Cd ranging from 0.4 to 1311,0.1 to 5.8, and 0.05 to 55 mg/kg, respectively. Standing biomass averaged 3.3 Mg/ha on the stabilized Welz waste zone by the end of the third growing season (1997). The revegetation of much of the Doerschel material area failed initially because of extremely high salinity (16 dS m-1), high content of water soluble metals (Cd in particular), and heavy compaction. The area was capped (15 cm) with waste lime and retreated with bio-solids (300 Mg/ha) in 1995, and standing biomass averaged 2.9 Mg/ha in the fall of 1997. The observed plant response to bio-solids and lime indicates this approach to be an environmentally beneficial technology as compared to the traditional methods utilizing topsoil covers.

Jan 1, 1999

By Lance Kolbush, Alex Vaughn, James Fisher, Michael Barish, Tony Toney

Somerset International has worked to enhance the recovery of sub-20 micron particles in our patented Sub325 Systems by introducing chemicals in the systems prior to the centrifuge. This paper details four cases of such enhancement. Two on the fine coal recovery side at a 325 tph plant in Central PA and Warrior Met Coal 7 plant. Two on the tailings dewatering side at a 1200 tph Southern WV plant and at Warrior Met Coal 7 plant.

Feb 22, 2026