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By David R. Maneval

The mining of coal in Alaska receives special treatment in the Surface Mining and Reclamation Act passed by the U.S. Congress in 1977 (PL95-87). Section 708 of the Act required that the National Academy of Sciences (NAS) perform a study of "Surface Coal Mining Conditions in the State of Alaska, In Order to Determine Which, If Any, of the Provisions of the Act Should be Modified with respect to Surface Coal Mining Operations in Alaska'. The special committee on Alaskan Coal Mining and Reclamation of NAS completed their study in 1980 and prepared their report (NAS, 1980). At this time, the Secretary of the Interior and the Congress have taken no special action with regard to either special regulations geared specifically to Alaska or to submitting special draft legislation to the Congress requesting amendment of PL95-87. The Alaska Department of Natural Resources (DNR) has drafted legislation which was submitted to and passed by the 1982 session of the State Legislature. The State regulatory agency has also drafted the requisite regulations necessitated by the amendments to the State's Basic Coal Mining Act. It is expected that by mid 1983 DNR will have applied for "primacy" to the office of Surface Mining, U.S. Department of the Interior (OSM). They will be submitting the amended State Law, the revised State Regulations and an operational plan as called for by OSM regulations. The presumption is that primacy will be granted to the State of Alaska under PL95-87. The Usibelli Coal Mine continues to be the only operational commercial mine for coal in the State of Alaska. It produced 7.26 x 10 kg (8 x 10 " T) of coal during 1981. The current mine was started in 1920 by Captain Lathrop, an early developer and pioneer in Alaska. It was continued by Emil Usibelli and was taken over after the death of E. Usibelli (in the 1964 earthquake) by his son Joseph Usibelli who is the current President of, the firm3 Their latest improvement is a 27.5 m (36 yd. )Bucyrus-Erie Dragline which handles most of the overburden removal. The coal is removed by a loader-truck combination. They are currently starting up the use of a unit train loading facility which handles forty cars every two hours. This loading system was a development necessitated by the Sun Eel Export contract. The Alaskan Railroad was a major cooperator in the development of the first unit train loading facility in Alaska.

Jan 1, 1982

By Hayward B. Oblad

The effects of eight independent variables on froth flotation product yield, ash content, and coal recovery were studied using laboratory batch flotation of 0.6 am x 0 coal. The eight flotation variables investigated were air feed rate, pre-dispersion of collector oil, impeller speed, product collection time, initial solids concentration, collector conditioning time, frother (methyl isobutyl carbinol) concentration, and collector (No. 2 fuel oil) dosage. The two-level Plackett-Burman screening design and the three-level Box-Behnken design were used. Within the ranges studied, air feed rate had no effect on product yield. Pre-dispersion of collector oil, impeller speed, product collection time, initial solids concentration, and collector conditioning time showed only minor effects on the product yield and quality. Frother concentration (mg/L) in the process water and collector oil dosage (g/kg) were shown to be the dominant independent variables in coal froth flotation. Flotation experiments that vary initial solids concentration at constant frother dosage (g/kg) confound the effects of frother concentration (mg/L) and solids concentration. The dominating effects of frother concentration and oil dosage on coal recovery and froth product ash content are illustrated with three-dimensional plots. The relationship between froth product ash and coal recovery is also clearly illustrated by the flotation data.

Jan 1, 1985

By Francis J. Quinn

The Natural Gas Act, of 1938, which put interstate pipelines under the jurisdiction of the Federal Power Commission, did not place a protective competitive shield around such companies - nor does any provision of the act guarantee them a profit. Natural-gas pipelines are competitive with each other and also with the coal and oil industries. Gas distributing companies must compete not only with the coal and oil industries, but also with the electric industry. Natural gas has captured markets from oil, which had taken them from coal. Oil men contend that gas prices have: been, held to an artifically low level by regulation. The electric industry is moving into the space-heating market, which pleases the coal people because the coal industry's largest customer since losing the railroads to dieselization has been the electric companies. The coal industry is attempting to monopolize the industrial and electric generating market through government intervention, and this is being done under the guise of concern for the national welfare through advocation of a "National Fuels Policy purporting to, further the cause of fuel conservation. Such a policy is contrary to American principles and would result in the individual's loss of freedom of choice and ultimately, in less reserves of preferred fuels because of diminished exploration efforts.

Jan 1, 1961

By R. B. Lantz

Low Froude Number (Fr) theory* predicts that stably-stratified fl& around a terrain obstacle will divide into a lower layer passing essentially horizontally around the obstacle and an upper layer passing essentially over the obstacle. The prediction was formulated by Sheppard (1956) and Drazin (1961) and confirmed experimentally in the towing tank model d experiments of Hunt et a1 (1978) and the atmospheric full scale experiments of the US EPA Complex Terrain Model Development Program (1982- 1985). The US EPA Complex Terrain Dispersion Model, currently under development, employs the layering principle with the flow in each layer calculated independently by potential flow (PF) theory after the layer thicknesses are established according to a simple function of Fr, i.e., Hc /H = 1 - Fr where Hc is the dividing streamline freight and E is the obstacle height. Use of PF theory in the CTDM is attractive because numerical solutions can be obtained simply and economically, as compared to lengthy Navier-Stokes (N-S) solutions, but realism is sacrificed in creating a surface of discontinuity between the tm layers and eliminating the effects of shear and gravity in each layer.

Jan 1, 1986

By Frank W. Schmechel

The subsidence monitoring program at the Old Ben No. 24 Mine was planned in 1976 as part of the on- going demonstration of longwall mining. The construction and installation of the network of surface subsidence monuments was started in Play of 1976 and completed four weeks later after which an initial reference survey was made of all surface monuments. Mining of the first longwall panel started in September of 1976 and was completed in May of 1977. Mining of the second panel started in August of 1977 and is continuing at this time. The Automatic Data Acquisition System (ADAS), which is the subject of this paper, was installed over the second panel on March 29, 1978 near the panel center (Figure 1) and approximately 104 meters (370 feet) in front of the face position at that time. Mine No. 24 is located approximately 5 kilometers (3 miles) Northwest of Benton, Franklin County, Illinois. Coal is being mined from the Illinois (Herrin) No. 6 seam which is at a depth of about 189 meters (620 feet) at the site. The Herrin No. 6 is up to 2.7 meters (9 feet) thick in the mine but a constant thickness of 2.1 meters (7 feet) is being mined by the demonstration longwall with both roof and floor coal being left for stability. Although the seam is flat laying at the mine, it dips north- ward regionally. Topographically, the surface over the demonstration panels is essentially flat and low laying with several areas of standing water. The Rend Lake Dam (United States Army Corps of Engineers) is about 305 meters (1000 feet) north of the demonstration site.

Jan 1, 1979

By Richard A. Grieve

A 63.5 metric tons per hour (70 TPH) demonstration coal preparation plant was constructed on the Iowa State University campus, Ames, Iowa, as a part of the Iowa Coal Project funded by the state of Iowa and administered through the Energy and Minerals Resources Re-search Institute. Processing equipment in the plant circuit includes a heavy media separator, concentration tables, separating and dewatering screens, and conveying equipment. Coal samples of size 907 metric tons (1000 tons) with sulfur contents ranging from 2.5 to 8.75% sulfur from seven mines in the state of Iowa have been pro-cessed in the plant. Sulfur reductions have averaged 35%. With ash reduction averaging 45%. Equipment for advanced fine coal beneficiation research is currently being installed in the plant to include a slurry pretreatment circuit, froth flotation, oil agglomeration, pelletization, hydrocyclones, advanced design thickener and disc filtration.

Jan 1, 1978

By A. G. Fonseca

The effects of coal cleaning, coal combustion and flue gas particulate removal systems on the partitioning of 12 trace elements were investigated. This study was prepared to help document the fate of trace elements in modern coal preparation plants and coal-fired utility boilers. The coal cleaning data were obtained from several coal preparation plant operations. The CONSOL 1. 5 MM Btu/hr pilot combustion and electrostatic precipitator (particulate removal system) test facility was used to develop the combustion systems data. A comparison with the very limited amount of published data from utility boilers is presented.

Jan 1, 1993

By J. R. Schafler, J. L. Brinkman

"Since the year 2000, 59 miners have lost their lives to explosions occurring in underground coal mines in the US. More accurately, those explosions were methane ignitions that propagated through the mines due to coal dust involvement; despite current explosion prevention standards. There are 4 basic strategies employed to manage the risk of coal dust explosions in many other coal mining countries around the world: removal of the coal dust, wetting of the coal dust to prevent it from becoming airborne, mixing of the coal dust with stone dust to increase the total incombustible content, and explosion activated barriers which make the entire roadway inert. However, American standards only mandate the first 3 of these 4 methods. It is possible that US coal mine safety measures could benefit from the implementation of the 4th method, the use of explosion barriers. This paper will discuss differences/similarities in barrier regulations used in other countries, as well as some potential difficulties with adapting a stone dust bag barrier system to US underground coal mines. Also, details and feedback gathered from two operating mine site trial barrier installations will be shared.INTRODUCTION Since the year 2000, 59 miners have lost their lives to explosions occurring in underground coal mines in the United States (US); 29 miners were killed at the Upper Big Branch mine in 2010, 5 at the Darby Mine No. 1 in 2006, 12 at the Sago Mine also in 2006, and 13 at the Jim Walter No. 5 Mine in 2001.[14] To be more accurate, the explosions that killed those miners were methane ignitions that propagated through the mines due to coal dust involvement.[18, 19, 20, 21] These deaths occurred despite current explosion prevention strategies, standards, and regulatory oversight. This poses the question, can more be done in the US to prevent coal dust explosions and their widespread damage. In review of current practices and regulations from several large coal mining countries, a disparity in prevention strategies arose. The main difference between the US and other countries was that the US does not encourage, mandate, or regulate the use of explosion barrier systems as an additional coal dust explosion mitigation measure. This raised many questions. First and foremost was whether or not the US coal mining industry and its miners could benefit, in terms of safety and fatality prevention, from the implementation of the explosion barrier systems that are used in other countries. Furthermore, are there significant differences between the coal mines in countries where explosion barriers are used and US coal mines, which would preclude the system from being adapted and implemented in the US? Also, what are the similarities and differences in explosion barrier systems, use, and regulations between other countries that use them?"

Jan 1, 2017

By Robert D. Schmidt

The US Bureau of Mines is cooperating with Cyprus Mineral Park Mining Co., Columbia University, and the US Geological Survey in investigating the feasibility of applying in situ leach mining methods to fracture-hosted, supergene copper sulfide (chalcocite) ores. This paper presents the initial findings of mineralogical, hydrogeological, and geochemical characterization studies conducted at the Mineral Park mine, located in the Wallapai mining district of northern Arizona. A design for in situ leaching is proposed that would minimize the need for blasting prior to leaching, and would enable economical development of deep reserves at the Mineral Park mine. The in situ leaching design would also reduce the potential for long term acid rock drainage.

Jan 1, 1995

By B. M. Flohr

Railroads are cost competitive with trucks for hauls greater than 500 miles - WRONG. Today I will tell you about many rail movements of less than 100 miles throughout the country. Rail is a short haul transportation alternative you must consider. Transportation today is the largest controllable cost in the total cost of production of goods. In fact it is the one cost area where aggressive management, using new tools, can achieve significant reductions. You can't control the price of metals in the world market, you can't control labor rates since they are tied to industry norms, and the price of raw materials are relatively insensitive to specific price reductions to your firm. Transportation is the one area where major savings are now being realized. Sample Movements First, I will give you several examples of short haul rail moves to make you a believer that they do exist. Then I will show you the reasons why railroads suddenly "like" short hauls.

Jan 1, 1986

By M. A. Trevits

The explosion hazard presented by methane gas in coal is confronted daily in the mining industry. Research has developed several viable methods for gas control in addition to conventional dilution by ventilation. Such methods include the drilling of horizontal or cross-measure boreholes from a mine opening and vertical boreholes hydraulically stimulated in advance of mining or for gob gas drainage. The long-term production history of five gas drainage installations was studied. Three installations were completed in the Pittsburgh Coalbed: two in West Virginia and one in Pennsylvania. The remaining installations were completed in the Mary Lee Coalbed in Alabama and the Sunnyside Coalbed in Utah. The types of drainage methods utilized included horizontal and vertical boreholes. The length of production studied ranged from 860 days to 36 years. The cumulative production from the five sites was in excess of 155 Mm3, representing a significant volume of gas.

Jan 1, 1985

By K. C. Kocsis

"Diesel-powered equipment has allowed the mining industry to raise production rates and significantly improve productivity, as it is rugged, mobile and reliable, but its widespread use in underground mines has generated concerns regarding the exposure of mine workers to harmful diesel engine exhaust gases and particulate components such as diesel particulate matter (DPM), which has recently been classified as a human carcinogen by the International Agency for Research on Cancer. The agency expressed further concerns that workers’ exposure to high DPM concentrations can increase the risk of cardiovascular, cardiopulmonary and respiratory illnesses. Three emerging technologies could have the ability to replace dieselpowered equipment and remove DPM from underground mines: fuel-cell-powered mining equipment, battery-powered mining equipment and advanced material handling systems. This paper reviews them and assesses whether they have reached the point where the pollutants emitted by diesel-powered equipment can be removed from underground mines through the introduction of zero-emission mining equipment and power systems. Information is also provided from the results of a feasibility study, including a detailed cost benefit analysis, carried out at six Canadian and nine U.S. underground mines, which looked at the possibility of replacing diesel-powered production equipment with fuel-cell-powered equipment. The remarkable pace at which battery technology is progressing is also reviewed, and the feasibility of replacing diesel-powered mining equipment with battery-powered equipment is assessed. IntroductionHazardous pollutants in underground mines. Why is it important to remove diesel particulate matter (DPM) from underground mines? Over the past 40 years, diesel-powered equipment has allowed the mining industry to achieve rising production rates and major improvements in productivity, as the diesel engine is an economical source of power and diesel-powered equipment is usually rugged, mobile and reliable. On the negative side, the toxicity of some diesel exhaust gases is well known (Grenier et al., 2001), and the widespread use of diesel-powered equipment in underground mines has generated increasing concerns about the occupational exposure of mine workers to harmful diesel engine exhaust gases and particulate components such as DPM. Diesel equipment also entails other hazards like heat and humidity. Exposure to excessive heat can cause heat illnesses, such as heat rash, heat exhaustion and heat stroke (Donoghue, 2004; Roghanchi et al., 2016), and a hot and humid underground environment negatively affects the efficiency of the workforce, which may result in a decline in production output (Roghanchi et al., 2017)."

Jan 10, 2017

By LeRoy D. Loy

The coal mining industry must be able to compete with alternate sources of fuel for the utility and industrial customers. If the industry is unable to control transportation costs, either due to government interference, or for other reasons, then mining costs must be kept down. Australia, South Africa, Canada, (and later Colombia) will take larger shares of the export market if mining costs are not kept competitive. The government's environmental regulations must be met without incremental increases in mining costs. Entrepreneurial instincts must be retained by the industry to provide for their investment in the future. What are the Problems with Existing Research? Government funding for coal mining research has been reduced or virtually eliminated. BCR (Bituminous Coal Research) is now a membership- supported organization, but its primary focus has been on health and safety-oriented research. BCR, however, is now attempting to widen its scope and conduct other types of research. There are almost no funds in EPRI's (Electric Power Research Institute) program for coal mining research. Large mining companies do some research for their own purposes and needs, but this is proprietary and therefore results are not shared with the remainder of the industry. The mining industry as a unit is not undertaking productivity (systems) oriented research in any common or cohesive manner.

Jan 1, 1983

By E. D. Stephenson

As part of the British Steel Corporation?s development plan during the 1970?s, it was decided to concentrate its bulk steelmaking processes based on the BOS at 4 major Works with access to deepwater ore terminals, for the supply of high-grade imported ores. These 4 sites were at: - 1. Rarenscraig Works in Scotland where the ore terminal would be hilt at Hunterston on the west coast some 50 miles away. Bavenscraig was already an integrated Works but suffered from having to discharge ore 27 Glasgow tenxinus on the River Clyde, which could only accommodate vessels up to 25,000 tonnes. In the future, ore was to be unloaded at Runterston and shipped by a rail-link into Ravenscraig, The new ore terminal would have the potential to unload vessels up to 300,000 tonnes. - 2. Port Talbot Works in south Vales where the existing harbour was developed to discharge large ore carriers. This again was an existing Integrated Works and the benefits of the new harbour also applied to Llanwern Works which was another integrated Works some 50 dies to the east, which would now receive ore from Port Talbot.

Jan 1, 1980

By R. H. Roberts

The Environment Weipa is located at 12° south latitude on the west coast of Cape York Peninsula, North Queensland, Australia. The climate is tropical with most of the 1 600 mm. average annual rainfall falling between November and March. During the short winter months (May/ August) the weather is clear and pleasant, with temperatures seldom exceeding 27°C.Throughout the remainder of the year, conditions are frequently oppressive due to consistent high ambient temperatures accompanied by high humidity. The terrain is of low relief, and generally not more than 6 to 10m. above mean sea level adjacent to the coast. The coastline features numerous short estuaries which discharge run-off from the heavy rains collected by creeks and rivers. The whole area is covered by an open forest, the predominant species of which is Eucalyptus tetradonta. These eucalypts have only limited commercial value and are heavily infested with termites. Despite the fact that Weipa is close to the location of the first reported sighting of the Australian coastline by a European (William Janz - 1606), it remains very isolated. There is no developed road or rail connection to centres of population, so that transport of practically all products, personnel and materials to and from Weipa is by sea and air. Cairns (population 49 000) is 580 km. by air and 670 nautical miles by sea; Brisbane, the

Jan 1, 1977

By Mark P. Walsh

In recent years in situ leach mining has emerged as a viable technology for the recovery of uranium from strata in South Texas which contain relatively low concentrations of uranium ore. Because the ore bodies lie within groundwater aquifers, a significant determinant in the economics is the requirement that such aquifers be protected from contaminantion. Since ammonia is one of the constituents of the leach solutions now being field tested, one environ- mental problem to be resolved is the removal of ammonia at the end of mining. A second related question is the fate of the ammonia which is not removed by the restoration procedure. This paper considers the displacement and migration of ammonium in a flowing electrolyte with concomitant ion exchange. The ion exchange is an important feature since, during the solution mining phase, ammonium saturates the mineral exchange sites and must be removed from these sites. A mathematical model is used to simulate this process and the model is tested against the results of laboratory experiments. It is found that the simulations are adequate if an appropriate selection of parameters is made. The model is then used to investigate the effect of cation composition and concentration of the restoration medium as well as dispersion on the overall effectiveness of the process. It is concluded that increasing the concentration of monovalent ions in a solution containing a mixture of both monovalent and divalent ions decreases the adsorption selectivity of the divalent ions with respect to all monovalent ions including ammonium. Thus increasing the ionic concentration of a restoration fluid by increasing the concentration of a nonselectively adsorbed (with respect to ammonium) ion may have a very limited benefit. Dispersion attending the flow of fluids in a porous medium is also shown to be an important factor. The effect of dispersion can greatly reduce the benefits of having a displacing cation which is adsorbed selectively with respect to ammonium. Since dispersion increases almost linearly with fluid velocity, an optimum displacement rate may exist.

Jan 1, 1979

By James S. Falcone

Soluble sodium silicate materials have well known applications in flotation for desliming, selective depression and corrosion control. Recent advances in the understanding of the complex polymeric nature of silicate solutions using NMR spectroscopy, combined with our studies of the effects of polymeric silicate anions on metal ion activities in solution, oxide mineral surface charges and surfactant adsorption on clays are related to beneficiation processes. The results of these studies indicate the sodium silicates can be used to cause a solution chemistry and particle surface charge characteristics favorable to enhanced effectiveness in typical ore beneficiation systems.

Jan 1, 1981

By P. C. Thakur

Horizontal drilling in coal mines is a relatively new technology. The earliest recorded drilling in the United States was done in 1952 at the Humphrey Mine of Consolidation Coal Company for degasification of coal seams. Spindler and Poundstone experimented with vertical and horizontal holes for eight years. They concluded in 1960 that horizontal drilling in advance of underground mining appeared to offer the most promising prospect (for degasification) but effective and extensive application would be dependent upon the ability to drill long holes, possibly 300-to 600 m, with reasonably precise directional control and within practical cost limits.(1) Mining Research Division of Continental Oil Company, the parent company of Consolidation Coal Company, began a research program in the early 1970's to achieve the above objective. The technology needed to drill nearly 300 m in advance of working faces was developed by 1975 and experiments on advance degasification with such deep holes began in 1976. Preliminary Its of this research have already been published.(2) To date nearly 4500 m of horizontal holes have been drilled for advance degasification and earlier results were reconfirmed. In summary, these are: 1) The greatest impact of these boreholes was felt in the face area where methane concentrations were reduced to nearly 0.3 percent in course of two to three months from original values of nearly 0.95 percent.

Jan 1, 1979

By R. Froidevaux

Geostatistical estimation techniques were customized to enable forecast of production figures at the Silver Bell uranium mine (Uravan District). Surface drill hole data were used to provide a block model of kriged estimators of average uranium grades. The recoverable figures, such as ore-waste ratio and ore grade, are then deduced from regressive curves previously obtained from underground information and production data. Cross-validations of the entire model were performed and were found positive.

Jan 1, 1981

By Saul Escalara

Data on sulfonate adsorption by silicate minerals are very scarce in the literatures. Perhaps the only comprehensive paper written on the topic was done by Fuerstenau and Bhappu (1); this work dealt exclusively with quartz but included many important suggestions as to the form and nature of the hydroxy-sulfonate species of some cations formed during the conditioning step and their effect on the flotation response of quartz. Another paper by the same authors (2) contains additional data on the role of hydrolysis in sulfonate flotation of beryl. As postulated by Fuerstenau and Bhappu, a solid form of cationic sulfonate functions as the collecting species to produce flotation of quartz and beryl. According to the authors, the solid compound is a hydroxy-sulfonate of a given cation, where the hydrogen of the hydroxyl part provides a means for bonding of the species to the mineral surface; thus, the presence of hydroxyl in the neutral precipitated compound is of primary importance to produce flotation. Although the preceding examples illustrate the effect of a sulfonate collector in silicate systems other than plagioclases, they are important as examples of processes of hydroxy-sulfonate complex formation. Since the plagioclase minerals con¬tain Ca(II) and Al(III) cations, which are very reactive in sulfonate media (1), the formation of hydroxy-sulfonate compounds with these cations released from the solid phase may well prove to be the cause for their flotation.

Jan 1, 1973