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By Hitch M.

Many mining wastes, especially those from the metal mining industry, have traditionally been treated as a matter of little or no value and in practice a cost burden. Some wastes, due to their reactivity characteristics, have emergent values that go beyond purely economic and into the environmentally beneficial realm. This paper discusses the changing paradigm of mine waste management. Such fundamental parameters such as cut off grade, and strip ratio, are positively impacted by the revaluation of waste rock material. Mine rock waste can now be seen as a commodity of value, similar to the underlying ore being mined and influences the economic performance of suitable projects. This valuable material can be used for industrial purposes including acid neutralization as well as the capture and long-term disposal of anthropogenic carbon dioxide. The Turnagain Nickel project, located in northern British Columbia serves as an example of how waste rock material can become an important matrix for carbon capture and sequestration and can benefit economically from it. By producing material that has emergent economic value as well as carbon capture and sequestration capabilities, the sequestration matrix producer is a beneficiary of new carbon credits that have a market value and is looked upon favourably by regulatory authorities and affected stakeholders.

Jan 1, 2010

By Glenn A. Squibb

An example of market development is described. The market in rail-lake movement of coal is vital to a rail carrier because of its location. This market is threatened by nuclear and other competing fuel sources and by depressed all-rail unit train rates, The first step to develop the rail-lake transportation market consists of rate adjustments and tariff changes to force tighter scheduling of mines, railroad, port and boats, and thus reduce cost. The second step provides a surge pile at the port to eliminate most of the seasonal disadvantage of rail-lake movement and reduce car detention at the port to almost zero.

Jan 1, 1966

By T. Hackett

Western underground coal reserves are tremendous, but recovery in western seams can be poor because of mining problems caused by deep cover, geologic anomalies, and thick seams. For instance, many seams contain a rock parting too thick to be extracted economically with the coal. This forces the operator to mine the coal above or below the parting. Subsequently, the rock pressures induced by mining make the part left difficult or impossible to extract by standard mining methods. Because upper and lower parts of the seam are frequently of minable thickness, the presence of rock partings can result in a significant loss of coal. Given a longwall recovery of 60 pct and equal thickness for the two parts of the seam, overall recovery is reduced to less than 30 pct if one part only is mined. The coal left in place is unavailable to meet the nation's energy needs, or to produce revenues for coal companies or government. [ ] Multi-slice longwall mining has the potential to recover the portion of split seams that are now left in the mine. Using superimposed standard longwalls with chain pillars, overall recovery could be doubled, depending on panel and pillar widths. Using a combination of advancing and retreating longwalls in descending slices, overall recovery could be improved to more than 80 pct. Because of the potential for improved recovery, the Bureau of Mines is analyzing the ground control factors affecting multi-slice longwall under western mining conditions and is conducting field trials at a planned multi-slice operation.

Jan 1, 1987

By Geoff Beale

In terms of their hydrogeology, most open pit mines can be divided into three categories. There are mines that occur above the water table, mines that extend below the water table in high permeability rocks and mines that extend below the water table in low permeability, tight formations. Mines that occur above the water table do not experience major ground water seepage. It may some- times be necessary to construct in-pit trenches and sumps to remove water from precipitation. But dewatering or enhanced drainage measures are typically not required. Open pits that extend below the water table in high permeability rocks find it cost-effective to pump from dewatering wells. This is done to lower the water table below the working pit floors, creating dry or depressurized conditions in advance of mining. If the rocks in the mining area are homogenous, complete drainage of the entire mining area may be achievable by pumping from wells. In this case, it is not necessary to consider drain- age enhancement. However, there are many open pits and excava- [ ] tions that can lower the water table using conventional wells, but for which drainage enhancement is also an integral part of the dewatering system. The Sleeper Mine in Nevada is an example of this. Hydraulic layering at Sleeper has prevented downward drainage of water as the main water table is lowered. In addition, there are many mines that have areas of low permeability wall rocks that do not freely drain as the surrounding water table is lowered. Ground water seepage also creates difficulties in mines that occur below the water table but for which lowering of the water table using conventional wells is not feasible because of the overall low permeability of the rocks. The volumes of water involved may be small. However, it is necessary to deal with all of the water inside the pit as mining proceeds. It is not possible to dissipate pore pressures in the wall rocks in advance of excavation.

Jan 1, 1997

By H. Kempton

New methods for remediating metals-contaminated groundwater include in-situ emplacement of highly adsorptive substrates to permanently retard solutes. Substrates are introduced by sequential injection of soluble components that precipitate in the aquifer, forming a permanent high-retardation zone. This method overcomes the factors that limit pump-and-treat remediation; i.e, long-term source loading and slow desorption. Column tests demonstrated efficient substrate emplacement, increasing retardation coefficients of Cr(VI) by 20 and As(V) by 40. Similar effectiveness is expected for other heavy metals. Simulations using a coupled advective-geochemical model accurately matched substrate emplacement and arsenic attenuation, allowing extrapolation to other constituents and larger-scale applications.

Jan 1, 1999

By Dave G. Osborne

With the growing exportation of coal from North America to the Pacific Rim countries and Europe, has come an increasing awareness of the need to determine economically optimized amounts of incombustibles (ash and moisture contents) for the shipped product. Despite the fact that demand bas caused a steady improvement in selling price, particularly for thermal coals, growing production and transportation costs have compelled producers to keep a sharp eye open for ways and means of minimizing the latter since this probably represents the greatest single potential for making savings. Consequently the Coal Industry has become acutely aware of the economic ramifications of eliminating moisture in particular, thereby producing further saving in the cost of transportation of product from the mine to the consumer. There is, however, a lower limit to which dewatering or drying can be taken and this relates to dustiness which is a function of the characteristics of the coal and the methods used for handling and storage during trans-shipment. Overdrying can lead to serious dust losses and difficulties in handling particularly if the coal contains a large proportion of fines. The ways and means for achieving this "happy medium" of optimization in moisture removal are seemingly undergoing gradual modification largely assisted by the following factors. a) Improvement in effectiveness of coal dewatering and drying equipment. b) Improvement in operational availability and utilization of the equipment. c) The development of surfactants, polymer flocculants and other agents which in many cases can be almost tailor made to suit specific applications.

Jan 1, 1982

By Silver Miller, William A. Vogely, J. C. Emerick

After location and verification of exploitable mineral resources, mineral development re- quires capital goods, labor, and energy to extract the deposit. In addition, a growing social awareness of the need for a healthy environment re- quires inclusion of environmental burdens to the total costs incurred. This is because mineral development is detrimental to the environment in a number of ways. All mining .operations involve the separation of valuable minerals from the surrounding waste rock, which in turn re- quires permanent disposal of unwanted or un- used materials. Mine overburden, wastes, and tailings are often transferred to peripheral areas where they remain as unsightly features in the natural landscape. Some mine spoils contain harmful or contaminating substances as heavy metal salts or acid forming materials which subsequently are released to the environment. Many types of mining operations handle significant quantities of water during extraction or beneficiation processes. When discharged, the quality of such water often is unsuitable for residential, agricultural, or recreational use. Since mining activity disturbs the natural vegetation in the project area, water may be allowed to transport soil materials into streams, causing erosion and siltation. In particular, surface mining operations disturb the top layers of soils, resulting in losses of productivity for long periods of time. Excavation, transportation, and further processing of large volumes of both ores and waste materials generate substantial quantities of particulate and gaseous emissions, some of which contain metal dusts or compounds of sulfur. Such fugitive and point source emissions can be transported beyond the confines of mineral operations to cause annoyance and damage at more distant locations. Environmental degredation or pollution can be viewed as the alteration of the environment by man through the introduction of materials which represent potential or real hazards to hu- man health, disruption to living resources and ecological systems, impairment to structures or amenity, or interference with socially desired uses of the environment. The significance of environmental degradation is reflected in its effects on a range of receptors, including humans as well as the resources and ecological systems upon which we depend. Pollution also is judged in the social context of damage to environmental structures and amenities. The demand for restoration and maintenance of environmental quality presents the mineral industry with a challenge to successfully man- age discharges and returns to the environment in order to avoid undesirable and harmful consequences. AIR QUALITY Impacts of Mining and Beneficiation Operations Air quality generally is degraded by mining operations through the addition of dust or total suspended particulates (TSP), carbon monoxide (CO), sulfur dioxide (SO2), nitrogen oxides (NOx), and hydrocarbons (HC) to the atmos-

Jan 1, 1985

By Kan Aketa

The Japanese iron and steel industry has been developed remarkably, supported by the increase of steel demand. In particular, progress in various technical aspects of the ironmaking process, including burden materials, equipment, and operation has greatly contributed to the increase in productivity and the reduction of the fuel rate in blast furnaces. With the recent rise in the price of petroleum, the conversion of the energy source from oil to coke has resulted in a temporary increase in the fuel rate of blast furnaces.

Jan 1, 1982

The surface of chalcopyrite was studied in situ in aqueous solution by an atomic force microscopy (AFM). The AFM images showed that some absorbate in patches was detected on the mineral surface, after the chalcopyrite sample was soaked in 5x10-4M potassium ethyl xanthate (KEX) solution at pH 11 for 10 minutes. These patches increased in size with time elapsing. At the same time, as shown by the obtained AFM force curves, the adhesion between the AFM tip and the substrate increased greatly due to the adsorption. Rinsing with ethanol removed the absorbate from the chalcopyrite surface, as well as the big adhesion observed in KEX solution.

Jan 1, 2010

[The development of economically effective and safe methods of mining thick coal seams enables to involve considerable coal reserves into the energy resources in different countries all over the world.]

Jan 1, 1975

By F. N. Kissell

The Bureau of Mines used sulfur hexafluoride (SF6) tracer gas to evaluate the effectiveness of gob ventilation and/or sealing practices at three coal mines, each having different problems associated with their mined-out areas. The purpose of these ventilation studies was to better understand whether current techniques employed for ventilation or sealing are successful at minimizing the potential for gob fires and explosions. The work performed at each mine is discussed: One is a longwall operation that uses ventilation to carry off hazardous gases, and two are room-and-pillar operations, each with far different concerns, that seal off the gobs to isolate them from the main mine ventilation. In all cases, employment of the Bureau's SF6 tracer gas technique resulted in answers to questions raised by the mine operators concerning the effectiveness of their gob ventilation or sealing practices in preventing mine fires.

Jan 1, 1987

By J. A. Luppens

Five years ago, Phillips Coal Company decided replacing mainframe/workstation programs with a new package of PC software was clearly the best solution for computer reserve modelling. The system chosen was actually three programs distinguished by their power, cost, flexibility and integration, and ease of learning and use. Phase I involves the use of the "StratiFact" program for borehole data management and seam correlation. This phase is probably the most neglected, yet critical aspect of reserve evaluation. Phase II employs the "PC/Cores" package for modelling and volumetrics. Phase m is "PC-Cut" which provides mine planning tools including an automated cut generator.

Jan 1, 1996

By F. W. Brackebusch

Paste backfill is a pumpable, flowable, non-Newtonian fluid consisting generally of mine tailings and cement. Paste is prepared from dilute slurries of tailings. This is done by dewatering the slurries with conventional thickening or filtering. Backfill with a paste consistency is prepared by mixing dewatered tailings with cement and water to obtain the desired consistency of medium slump concrete. The paste is pumped with concrete pumps over relatively long (1 km or 0.6 mile) horizontal distances. More commonly, though, it flows by gravity down a mine shaft and then horizontally to the void being filled. Alternatively, cement can be added near the end of the pipeline. A certain proportion of fine particles <20 µm (<625 mesh) must be present in pastes but particles of aggregate can be added without significantly affecting the flow characteristics. Detailed testwork is necessary to design a system to prepare and place paste backfill. Testwork must determine dewatering characteristics, strength of mixes and friction in pipelines. Plants must be well engineered and controlled with PLCs because high quality control is necessary to prevent plugged pipelines and excessive pressures. Relatively small amounts of cement (3% to 5%) produce stiff backfill material 1.5 to 3.5 MPa (217 to 507 psi). The advantages of paste backfill in a mining operation include reduced mine dewatering, labor and materials savings, reduced tailings impoundment requirements, good support properties and reduced spills underground. In certain cases where more than 30% of the weight of the ore is sold as a product, the entire tailings stream can be placed underground. Paste technology can he used for surface or underground placement of tailings.

Jan 1, 1995

By John P. Cummings

Glass is the most unique substance which man has made. It is understood that Phoenician sailors playing on the beach in Mesopotanmia around 12000 BC, produced glass by the fusion of sand and soda in their campfire. Glass is unique for many reasons. However, let us consider the following. It is made of materials which are opaque and yet glass can be translucent, transparent, or opaque. It can be as soft as cotton or stronger than steel. It transmits light readily and yet is totally impervious to gases and liquids. It is chemically an inert, creates very little pollution in its manufacture. It is made of the most abundant raw materials on earth. It is readily recyclable and has little pollution in its disposal. Glass containers are made principally from sand (that is, silica), soda, which is sodium carbonate, and lime, which is calcium carbonate, plus decolorizers or colorants and cullet. The proportion of cullet, broken glass, in most glass tanks today is roughly 10 to 20% of the glass product. In most cases, the cullet used in the plant is glass from off-ware, or broken ware, which is a waste product within the plant. Cullet has the following advantages. It contains all of the raw materials normally used in a batch. It tends to melt at a lower temperature than batch, thus saving some fuel, and, finally, by forming a crust above the normal melting system, there is a tendency to cut down air pollution.

Jan 1, 1975

By Shan Mafi

he Broken Aro coal mine is located at the Woodbury Wildlife Preserve 11 km (7 miles) west of Coshocton, OH on State Route 541. Underground min¬ing at the 16-hm2 (40-acre) site took place during the 1910s. During the past five years, surface mining has occurred along the western and northern perimeters of the underground region. The Ohio Department of Natural Resources (ODNR), R&F Coal and American Electric Power (AEP) are involved in a project to remine the abandoned underground complex. The program also includes installing a mine seal made of fixated flue gas desulfurization (FGD) material. Previous mining activity in this area has resulted in an acid mine drainage (AMD) problem on portions of the reserve. In particular, a prominent AMD source is present in the Simmons Run drainage. The project goal is to eliminate or reduce the AMD that is discharging into the watershed. It was initially hoped that the Simmons Run drainage area could be economically mined. Accordingly, this area was included in the mine permit. However, experience with other previously mined areas on this reserve showed that the old mine workings were more extensive than originally thought. Old mine workings present several problems. The most significant are reduced coal recovery, poor coal quality and AMD liability. All of these problems increase mining costs. And the more extensive the old workings, the more significant the increase in cost. Based on R&F&apos;s experience with old mine workings in this area, it was decided that economic recovery of the Simmons Run drainage reserve was not possible. As a result, R&F excluded the Simmons Run drainage area from its early mine plans. Some time after it was decided not to affect the Simmons Run drainage area, R&F and ODNR&apos;s Division of Mining and Reclamation discussed the possibility of removing this area from the permit and attempting to correct the AMD problem as an Abandoned Mine Lands (AML) project. Specifically, the discussion centered around mining through a portion of the old mine workings to expose the mine openings in the highwall. Once exposed, the mine openings would be sealed using FGD material from the nearby Conesville power plant operated by AEP. In addition, there was interest in reclaiming the old tipple and associated gob pile located adjacent to Coshocton County Road 17 on the opposite side of Simmons Run. R&F attempted to eliminate the AMD problem by sealing the mine openings with FGD material. Once the seals were installed, they were covered with overburden. Monitoring wells were installed to determine the effectiveness of the seal and the inundation progress in the old mine workings as well as monitoring the quality of ground water. The project was jointly funded by revenue from the sale of the coal recovered during the project and AML funds. The FGD seal is expected to cause well water levels to increase above preseal elevations. However, the additional head pressure due to increased water depths in the underground mine may cause seepage through the bottom of the mine or out through the perimeter. The in¬creased water depth in the underground mine is expected to cause lower oxygen concentrations in the underground mine water. Since acidity is produced by oxidation of iron pyrites, less oxygen should result in better quality water. Monitoring wells will be installed before seal installation so that pre- and postseal water levels and well water quality can be determined. Surface sampling locations will be identified. These will be monitored before and after seal placement.

Jan 1, 1998

By Dale S. Preece

INTRODUCTION The Waste Isolation Pilot Plant (WIPP) is a research facility located in Southeastern New Mexico. The WIPP is being developed by the U. S. Department of Energy (DOE) to demonstrate the safe storage of defense-related radioactive wastes in bedded salt. Since the WIPP is a research facility. a number of large-scale in situ experiments have been planned and are currently under construction (Munson, 1983). These experiments were designed to study various aspects of nuclear waste storage in bedded salt such as mechanical responses and creep closures of drifts, thermal response due to heated canisters, and thermally-induced fluid migration. One purpose of the WIPP is to develop and demonstrate a general predictive structural analysis capability for a bedded salt repository. One set of experiments, called the Geomechanical Evaluation (Room G), is heavily instrumented to study the creep around several rooms with different configuration. A Layout of the Geomechanical Evaluation room is shown in Figure 1. One portion of it consists of wedge shaped pillar where two drifts intersect at an angle of 7.5 degrees. The pillar can be seen at the bottom of Figure 1. One purpose of the wedge pillar experiment is to study progressive pillar failure in the tip region. Another is to determine how nonuniform pillar thickness affects creep closure of the drifts. An important aspect of the experiments is the correlation between experimental data and corresponding pretest finite element analyses of the site. The finite element simulations serve two purposes. First, the computer simulations aid in understanding the experimental results by providing calculated stress. strain and displacement fields that cannot be measured directly. Second, comparison of calculated and measured drift closures serves as a method for validating or improving the finite element models and the constitutive models employed. The wedge pillar geometry required a 3-D finite element creep calculation. Results from these 3-D calculations will be presented in this paper. A 2-D plane strain double drift model which approximates the wedge pillar geometry at a slice perpendicular to the drift has also been performed and will be compared to the 3-D results in this paper. FINITE ELEMENT COMPUTER PROGRAMS Two finite element computer programs. JAC (Biffle, 1984) and JAC3D (Biffle. 1986), were used. JAC is a 2-D finite element program developed for quasi-static analysis of non-linear solids. It employs the conjugate gradient iterative technique to obtain a solution Spatial integration is performed using a single gauss point in each four node quadrilateral element. An hourglass viscosity technique is used to control the zero energy modes that occur with single point integration. The single point integration combined with the explicit nature of the program and exploitation of CRAY-1 computer architecture results in very efficient execution J4: results were compared to results obtained with eight other 2-D structural creep computer codes in the second WIPP benchmark exercise (Morgan, 1981) JAC3D was derived from JAC to treat 3-D finite element models and has many of the same characteristics including single point integration and hourglass viscosity. These characteristics have made 3-D creep analyses more reasonable by significantly reducing computation time The first exercise of the creep capability

Jan 1, 1986

By C. Orf. Chukabarah

Acoustic pollution (noise) is a significant mine environmental system problem. The U.S. Bureau of Mines (USBM), Environmental Protection Agency (EPA), Department of Labor (DOL) and other researchers have all performed contributory research on noise in mining environments. The present study addressed the problem of unavailability of a computerized, practical, routine, user-friendly, and user-editable, prose-styled application program with which one can determine (a) the noise exposure indices among mine workers, (b) mine system noise exposure level on time-weighted average basis, and (c) predictive relationships among mine workers&apos; age, prior exposure to abnormal noise levels, prior auditory pathologies and the risk/degree of mining-induced hearing impairment. Results showed that such a program ("NEIL") is accomplishable. Additional results revealed that most U.S. mines operate within the statutory noise exposure levels. Furthermore, the mine worker&apos;s age was statistically confirmed to be the main predictive risk factor for mining-induced occupational hearing impairment.

Jan 1, 1992

By Charles H. Ricker

Simulation models have been widely used to analyze the operations and characteristics of a variety of systems. Such models mimmick a projected reality by analyzing the interaction of the events, transactions, and facilities which combine to make up the system. The models are structured as a computer representation of the system components and their logical, precedence and timing relationships. The operation of the system is then simulated over some finite time interval to gather analytical and staistical data. This paper presents a method whereby bulk handling systems, either actual or proposed, may be analyzed by means of simulation models to project the enconomic consequences which may be expected from the system over some future time interval. An example is given to illustrate the construction of bulk handling simulation models, the derivation of performance data, and the analysis of the information with an eye to effective decision making.

Jan 1, 1974

By D. E. Munson, T. M. Torres, D. A. Blankenship

The Thermal/Structural Interactions (TSI) In Situ Tests are a series of large scale, well instrumented tests that have been constructed at the Waste Isolation Pilot Plant (WIPP) in southeastern New Mexico. As a precursor to the TSI tests, a ventilation drift (Room D) was mined, drilled and instrumented. This room provided the contractor an excellent area to practice controlled construction methods and was a proving ground for construction monitoring and documentation methods. All gages in this first room have been monitored since their initial installation, which has provided a small, but representative, data base. These data also were the first to be available from any TSI area for analysis. This paper discusses the construction activities in Room D and the data generated from the construction and drilling. Deformation of the room is compared briefly to numerical calculations that used a rather simple creep model as a reference. The constitutive model for salt, it appears, must be improved before it can predict the underground deformations.

Jan 1, 1986

By PATRICK R. TAYLOR, NICHOLAS BELLUSCI, D. ERIK SPILLER, VICTOR BRAMAN

Most of the world’s production of natural soda ash comes from the mining and processing of trona found near Green River, WY. The processing of trona ores to ultimately yield a high-quality dense soda ash product and reject the insoluble gangue species, primarily in the form of oil shale, is water and energy intensive. It is speculated, however, that the glass-manufacturing industry, which is the largest consumer of soda ash, may be able to use product of a lower grade and consistent level of the insoluble constituents. Thus, the viability of using sensor-based sorting to produce a beneficiated trona stream that would be fed to calcination was investigated. The study encompassed the preparation of a run-of-mine (ROM) Green River ore sample; selection of specimens sized 25 to 75 mm; imaging of the specimens by sensors based on X-ray transmission (XRT), color and laser-induced fluorescence (LIF); insolubles analysis of the specimens; and a bench-scale sorting test. Results of the study established that a correlation between the color of the individual ore particles and their insoluble content exists, and that a surface-detection-based sensor, particularly LIF, is apparently more suitable than XRT to produce a beneficiated trona stream. The bench-scale sorting test demonstrated that a 65 percent separation efficiency and a 70 percent recovery of trona could be achieved.

Feb 1, 2023