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By E. Watkins, S. J. Schatzel, V. Gangrade, R. Kimutis, J. Addis, C. Hollerich

The recent shale gas revolution in the United States has led to the drilling of hundreds of unconventional shale gas wells in active and future coal reserves in traditional coal-mining regions of Pennsylvania, West Virginia, and Ohio. This paper summarizes the impact of a shale gas well breach on the mine ventilation system of an operating longwall panel. This study utilizes a 1:30 scaled Longwall Instrumented Aerodynamic Model (LIAM) to simulate a single-panel longwall operation. The LIAM will be utilized to identify flow pathways and distribution patterns of gas from breached gas well scenarios in an operating longwall in the Pittsburgh Coal Seam. Sulfur hexafluoride (SF6) tracer gas is utilized to simulate a breached gas well. Preliminary findings suggest that the breached gas is diluted to regulatory levels and does not accumulate in the mine entries or in the longwall gob when the longwall panel is adequately ventilated. Overall, this study characterizes the potential interaction between shale gas wells and the mine environment in the event of a gas well breach, which provides critical information to the industry and regulatory agencies for improving safety, health, and welfare of miners.

Mar 2, 2022

By W. –E. Marx, M. Faber, R. Pollak, I. Astberg

INTRODUCTION Essentially three strategies are pursued in parallel for protecting the underground working force in mining against the consequences of methane ignitions which might lead to explosions: • Sufficient ventilation for avoiding the formation of explosive methane-air mixtures. • Avoiding sources of ignition caused possibly by electrical equipment or friction. • Structural explosion protection for limiting explosion propagation to the farthest-going extent for the case that methane is fired because of failing of the above preventive measures taken. The corresponding methods taken in mechanized roadheadings with point-attack roadheaders in German coalmining are subject of this paper. VENTILATION In ventilation of roadheading sites the following is to be considered in respect of methane control: • Sufficient air flows by volume being cycled to the heading face for diluting released methane to safe concentrations. • Sufficient local air velocities for effective mixing of methane and air in the whole heading site, in particular directly on the heading face and underneath the roof. Furthermore, ventilation needs to be laid out in a way that cut- ting does not result in health affecting dust exposure at any working place. Accordingly, the ventilation systems shown on Fig. 1 including primary and, if necessary, secondary auxiliary ventilation air ducts as well as dedusters, are used in roadheadings. This equipment is run according to the following principles: • If the roadheader is at standstill, the heading face is ventilated by the free air jet from the blowing duct closest to the face. In this operation phase the deduster is shut-down. • During cutting, the exhaust of the blowing air duct is automatically closed, and the deduster is taken into operation. The in- coming fresh air is now locally discharged via a lateral orifice, or distributed by Coanda-type ducts from the primary or secondary ventilation air duct. In this way, a stable dust wall not disturbed by the jet of the air duct is formed in front of the heading face. Only the ventilation air stream taken in by suction of the close-to-face deduster is passed through the inby zone of the heading face (over approx. 20 m). The clean exhaust of the deduster is dischayed to the roadway in some distance outby. Immediately at the heading face, methane accumulations possibly released by cutting are diluted by compressed-air jets from air-movers located near the roof which assure more rapid motion of the air without distuhing the dust wall. • In the zone of overlapping of primary and secondary duct and the deduster - that zone possibly is poorly ventilated during cutting - sufficient local air speed is assured by Coanda-type ducts or additional ventilation jets for avoiding methane accumulation. The regulations of the inspectorate specifies geometrical conditions to be met with these configurations of ventilation equipment. In-seam roadways are ventilated at rates > 0,5 m/s. For dedusters, present-day ventilation air flows are of 600-800 m+/ min. Ventilation monitoring and control is assured by units for measuring methane and ventilation air flows. If pre-set thresholds are exceeded or fallen short of, these measuring units shut-down - dependent on potential hazard - any not intrinsically safe electrical equipment in the roadheading, either totally or in limited zones. In addition, CO-measuring units near the roadway en- trance serve for early detection of mine fires. In spite of this ventilation layout and the equipment used and in spite of the water spray systems on the cutting head (discussed later in this paper) several cases of methane ignition and subsequent burning off (however, no explosions) have been recorded in the recent past. Therefore, the above-described ventilation is nowadays complemented in many cases by machine-mounted ventilation equipment for the immediate surroundings of the cutting head. Ventilation of the surroundings of the cutting head Investigations carried out subsequent to the above-mentioned gas ignitions have shown that the high ventilation air speed necessary for rapid dilution of methane could not permanently be arrived at in the following zones: • The direct zone of cutting, in particular during sumping. • The floor zone above the debris, predominantly below the cut- ting head. Accordingly, VOEST ALPINE-Bergtechnik, a producer of mining machinery, in cooperation with DMT developed for point- alttack roadheaders a novel machine-mounted ventilation equipment, the Jet-Block" (AERO SAFE Jet-Block) shown on Fig. 2. This system allows to ventilate the above-mentioned critical zones with high flow speeds. One AS Jet-Block is mounted on each side of the boom approx. 0.5 m behind the cutting head. The blocks discharge compressed-air jets with high energy from 10 nozzles per block into the hazardous zones (Fig. 3). Two nozzles of each jet block are tangentially oriented toward the upper circumference of the cutting head, the others are arranged fan-like with orientation to the heading face underneath the cutting head and the debris. The nozzle array of the blocks as well as the com-

Jan 1, 1997

The ability to increase and maintain dragline productivity is a key mine driver for the Coal Creek Mine. The Coal Creek Mine is owned by Arch Coal Inc subsidiary Thunder Basin Coal Company; located near Gillette, WY. Coal Creek Mine overburden stripping is primarily accomplished by a BE-1570W walking dragline in combination with cast blasting and dozer assist for bench preparation. The two main variables impacting dragline performance are maintenance reliability and operator skill levels. The mine?s most recent process improvement efforts have focused on its most valuable asset - the operator. Various techniques have been used to reduce variability in the dragline operator?s digging performance. Utilization and communication of operator performance data, statistics, and video reviews have been of great value towards achieving this goal. Operators are given a chance to critique operational tendencies from a third-person point of view, and are also presented statistical feedback to support observations. From these sessions, operators gain knowledge as to what portions of the dig cycle can be improved in order to reduce cycle time and increase productivity. BACKGROUND The BE-1570W walking dragline was commissioned at Coal Creek in November 2006 after relocating from Arch of Wyoming located in southeast Wyoming. The first two years of operation the machine was performing simple side cast stripping due to the low ratio. Coal Creek Mine is a multiple seam operation with overburden thickness ranging from 24 to 140 feet. Early in 2009 the ratio increased to the point where transitioning to cast blast/extended bench stripping was necessary. The current mining conditions consist of a mixture of both stripping styles where the ratio allows. The dragline crews running the machine consist of a mixture of experience levels ranging from 30+ years to only a few years. It has been in this digging environment and slightly inexperienced personnel that the focus has been set for improvement in dragline performance.

Jan 1, 2011

By Muhammad Zia-ur Rehman, Sajjad Ahmad Baig, Gao Lei Fu, Muhammad Mohsin, Sobia Naseem

The environmental sustainability is linked back to human sustainability; the sustainability development comprises the environment, society, and economics. This study mainly focused on mining sustainability and its impact on the environment of Pakistan. For measuring the level and environmental mining sustainability nature to Environmental Impact Assessment (EIA) of the world’s second largest salt mine “Khewra,” Folchi and Phillips environmental sustainability mathematics (PESM) models are applied. The results indicated that Khewra was deemed to be potentially sustainable for the environment and quality of salt. The results suggest the delicate balance of maintaining sustainability successfully, regarding the mining process in Pakistan which has been affecting the local environment and community so badly. The paper lays emphasis on the potential significance of the model’s application for the attainment of sustainable mining goal. This study is essential for researchers,

May 11, 2020

By D. J. Beeby

California's Surface Mining and Reclamation Act (SMARA) was passed in 1975 to identify and protect mineral resources in areas of high land use conflict and ensure reclamation of mined lands. Under SMARA, aggregate resource availability is quantified and compared to forecasted demand in specific market regions. Fifteen regions studied thus far cover 51,800 km2 (20,000 sq miles) and contain 45 Gt (50 billion st) of high-quality aggregate resources that have been legally designated as "regionally significant," providing a measure of protection previously unavailable. SMARA reports and state testimony at local hearings have supplied objective information and helped reduce conflict in mine permitting decisions.

Jan 1, 1987

By N. J. Ferguson

An upsurge in demand for Australian coal has seen a much needed programme for a new generation of coal ports. This paper discusses design concepts in planning a large modern terminal, with the 25 Nt/a Port Kembla and the 50 Mt/a Newcastle facilities as practical examples. The need is emphasised for a studied Master Plan, in-built materials handling flexibility and staged development. Trends in bulk ship design and loading methods are noted. Features of these Australian designs include methods of dealing with poor ground conditions, functional civil engineering for environmental protection and optimal marine structure designs.

Jan 1, 1982

By Ning Liu, Di Yin, Xuming Wang, Yongqiang Lu, Jan D. Miller

Air-sparged hydrocyclone (ASH) flotation technology has been evaluated for phosphate recovery from the central Florida phosphate deposits. As expected, it was demonstrated in pilot-plant tests that the ASH system has a specific capacity about 50-100 times higher than that of a traditional flotation cell. In the case of fatty acid flotation, single-stage ASH flotation produced a recovery of 75-77% in a rougher concentrate containing 24% P2O5 In reverse flotation with amine, the single- stage ASH system produced a phosphate recovery of 98% in a cleaner concentrate containing 31% P2O5. These results are comparable with those obtained at plant operations in the Florida phosphate industry. Based on these pilot-plant results, the effects of process variables are discussed in terms of separation efficiency. Subsequently, a 6-inch ASH system was fabricated and tested in a central Florida phosphate plant for reverse flotation in the amine flotation circuit. The high capacity of the ASH system was again demonstrated for the 6-inch ASH system. A single-stage phosphate recovery of 91% was achieved with a concentrate grade of 30% P205. During plant tests, it was established that porous tube plugging, the most significant engineering problem identified, was due to the poor quality of the plant water. Possible solutions to this problem are discussed.

Jan 1, 1999

By German Zambrana

The solution of the problem of beneficiation of cassiterite from its primary ore deposits is of fundamental importance to Bolivia. The process today involves a gravimetric treatment of the ore followed by sulphide flotation. During the last year, a cassiterite flotation stage has been added in several plants to treat the slime tailings. Although cassiterite flotation is already economical for the slime tailings and the mechanism of the process are understood, it is felt that further research could improve the results. In the past, considerable amount of research and test ark has been performed to select appropriate collectors to improve recovery, to increa¬se the grade of tin in the concentrate, to minimize the effect of metallic ions like Ca+2, Fe+2 and Fe+3 which prevent flotation, and to increase the pH of the pulp which now it can not be higher than 3.0. It has been reported that the halogen salts (1) like NaCl exhibit special surface affinity for cassiterite but none for quartz. These effect seems to be favourable for the selective flotation of cassiterite from silica minerals. In view of these preliminary results it was decided to follow the research accordingly: OBJECTIVES The objectives of the present investigation are: 1. 0 evaluate the influence of NaCl salts in quartz and cassiterite flotation.

Jan 1, 1971

By J. M. Dean

The MANpower SUPport Program (MANSUPP), a part of the Mine Management Support System (MMSS), allows an underground coal mine site user to determine manpower requirements for production support work by considering ongoing operations and current mine conditions. The objective of MANSUPP is to plan a detailed manpower structure for a mine by incorporating a production schedule, condition-modified work standards and management preferences to predict required manhours for various activities, for example, belt moves. The program is written in Quattro Pro version 3.0 (Lotus 1-2-3 compatible) utilizing the command language, macro and formula capabilities.

Jan 1, 1992

By Felicia F. Peng

Using granular media for removal of soluble manganese from mine water and industry waste stream has the advantage of forming a compact surface layer of manganese oxide coating on the media. This process can avoid the step involving the separation of voluminous sludge of manganese hydroxide by the high-pH method for soluble manganese removal. The removal of soluble manganese is accomplished by adsorption and oxidation. The adsorption of Mn(II) on the manganese oxide-coated media was rapid through the specific adsorption and may be due to the ion exchange of hydroxyl ions on the manganese oxide by Mn(II). In the subsequent step, the adsorbed Mn(II) form the intermediate manganese complex on the manganese oxide product is oxidized with dissolved oxygen or other available oxidant source in the aqueous solution. This paper presents the efficiency of removal of soluble manganese from mine water by using a laboratory fluidized bed and the recovery of manganese oxide coating on the anthracite coal particles. In order to accelerate the formation of the manganese oxide layer on the surface of anthracite media, dilute potassium permanganate solution is used as an active oxidant. The effects of operation parameters on the manganese removal including pH, flow rate, concentration of feed and oxidant dosage are evaluated.

Jan 1, 1996

By E. Bakhtavar

In this paper, problem of short-term production planning for dimension stone quarries was mathematically modeled using a binary integer programming. The model includes an objective function, which was founded as the minimization of the costs due to the total cutting planes of the blocks. This objective may cause to maximization of the net present value (NPV) in dimension stone quarries. During the mathematical modeling the essential constraints are dimension stone quarry capacities and the market demand, block accessibility for the equipment and the reserve constraints. As a base, an optimal size and shape of extractable blocks should be first assigned according to the available extraction technique and the market demand, in order to create a geological block model. Then an economical block model is provided by assignment of a value of ?one? for ore blocks and ?zero? for waste. Maximum profitability and minimum amount of the ore wastage can be gained using this plan and modeling.

Jan 1, 2012

By George E. Aiken

Agglomeration developments in the iron ore industry of North America are closely related to shifting patterns in commercially acceptable ore grades and even the definition of iron ores. These relationships have occurred mainly during the last 20 years. Many of these changes are an outgrowth of events which involved the history of the Mesabi Range. Although magnetic taconites had been discovered in the Lake Superior area about 1870, they remained unvrorked in part for lack of concentration methods and a generally unfavorable economic climate. Some 20 years later the rich Mesabi hematites were found beginning the era of direct shipping ores which continued through World War II. These Lake Superior iron ores included reserves of an estimated three billion tons. Following World War II, decreasing ore grades and rising costs began to force the closing of many underground iron mines. The early 50's saw the beginning of the decline in direct shipping ores and a spurt in produc- tion of natural iron concentrates. However, the market for unprocessed concentrates began to decline in the early 60's as agglomerated products and foreign ore s began to dominate the U. S. market.

Jan 1, 1973

By Richard M. Chamberlin

Perlite is an altered rhyolitic glass with 2 to 5 wt % water that expands or "pops" when heated quickly to plasticity while evolving steam to form lightweight, glass foam. Commercial perlite deposits in New Mexico are well-developed zones of chemical weathering (hydration) superimposed on highly permeable and thick glassy zones at the chilled upper surface and toes of high-silica-rhyolite lava flows and lava domes. The maximum tonnage of glass in these volcanoes was predetermined by their unique eruptive histories. New Mexico perlite production (80% of US production of 571,00 st) is mostly from the 3.9 Ma high-silica-rhyolite lava flows at the No Agua Peaks volcanic center. The primary vent at No Agua is defined by a 900 ft-high rubidium-rich composite lava dome, known as West Peak, that contains minor perlite reserves. Slightly less rubidium-rich lava squeezed out from under the west flank of the dome to form relatively thin (250 ft) but highly vesicular lobate flows that now consist of about 50 % recoverable perlite. Finally, rubidium-poor lavas were extruded from a radial dike on the northeast flank of the dome. These thicker (400 ft) flow lobes contain about 20 % recoverable perlite. The largest mass of lava does not always contain the most perlite. The thinner (west) flow at No Agua yields the largest perlite reserves rather than the large composite lava dome or thicker (east) flow.

Jan 1, 1994

By Charles F. Herbert

It is difficult to decide who most deserves credit for discovery of a mining district that has produced over 19.8 Mg (7,000,000 fine oz) of gold and still contains a large reserve of low grade ore. Fred Culver may have made the first discovery. In the summer of 1867, the ship's log of the Hudson's Bay Co.'s steamer Otter stated that Fred Culver had been found nearly lifeless from wounds, without provisions, but with some 2.3 kg (80 oz) of rough, placer gold in the bottom of his canoe; he told of finding a rich creek and an attack by Indians that caused the death of his two companions. The place of rescue was about 24 km (15 miles) southeast from the present site of Juneau. Possibly John Muir, the hero of modem environmentalists, should be given important credit. In 1879 he reported finding mineralization along what later became to be known as the Juneau Gold Belt, and it was his report that induced the cantankerous German mining engineer, George Pilz, to grub- stake some of the prospectors who had drifted into Sitka from the declining gold placers of Cassiar, British Columbia. Pilz also offered rewards to Indians who might report gold discoveries.

Jan 1, 1990

Asgco’s design of the Arrowhead Ceramic Lagging provides solutions to problems experienced with conveyor belt slippage around the drive pulley and severe wear problems on snub and bend pulleys. Asgco has developed a range of pulley lagging from ceramic, drive rubber and non-drive rubber lagging that is available in abrasion-resistant SBR and MSHA grade rubber for conveyor pulleys from slow belts all the way through to high-speed, high load belts. There is a growing need for a maintenance-free and reliable pulley lagging to ensure conveyor belts run to their highest efficiency.

Jan 1, 2006

By Ignacio Salazar

Somebody sure gave me the wrong title. I can talk much more freely about the impact of the anti-nuclear movement on the DRILLING industry in New Mexico. In a word, it is being "clobbered." It doesn't seem like very long ago that my brothers and I were busy trying to find enough new equipment (and trying to talk bankers into lending us enough money) to keep up with drilling work we could get. Seemed like no matter how hard we worked, and how much money we borrowed, we were always one step behind where we wanted to be. We had so many holes to drill that all our crews were working three shifts a day, and over several states. The nation needed energy, and we were ready to help supply it. Exploration and development drilling jobs were all going full-blast. We had trouble keeping up with them. With luck, we figured we'd be able to get all our equipment out of hock before all the necessary uranium mines were developed.

Jan 1, 1979

By Robert W. Bruhn

The prediction of damage to a structure that is to be undermined is generally a two step process. First, the expected ground movements (the displacements, slopes, curvatures, and strains) are estimated using available (often empirical) predictive methods or survey data from a site of comparable geology, topography, and mining geometry. Second, the prospects for damage to the structure are assessed by comparing the expected ground movements to tolerable limits, some of which appear in the technical literature as damage criteria. The inverse problem of relating observed building damage to causative ground movements involves essentially the same elements. In either case, the usefulness of published damage criteria to subsidence problems may be limited in all but the most elementary cases. This paper considers several cases where structural behavior and site specific details had to be taken into account in assessing the relationship between damage and ground movements.

Jan 1, 1986

By A. Bruynesteyn

I would like to talk to you today about microbiological leaching or, the solubilization of metal values due to the action of Thiobacillus ferrooxidans. Bacterial attack of sulfide minerals has been going on for centuries but only recently was it discovered that the acid and iron often found in coal mine drainage is produced by bacterial action on the iron sulfides in the coals. Not until 1950 was it proven that bacteria were playing a role in the dump leaching of sulfide ores. B. C. Research became involved in microbiological leaching in 1955 while examining mine drainage from the copper-zinc mine at Britannia Beach, north of Vancouver. Since 1955, B.C. Research has maintained a continuous re¬search program on microbiological leaching which, due to its applied nature, was put under industrial sponsorship in 1962. Most of the information pro¬vided in my talk today has been gathered under this sponsored research program and I would like to express our appreciation to the many sponsors who have made our work possible.

Jan 1, 1970

By B. G. Stone

"INTRODUCTION “Sampling is the process of taking a small portion of an article such that the consistency of the portion shall be representative of the whole” (Baxter and Parks, 1939) “An orebody is a mixture of minerals in proportions that vary in different parts of the mass. As a consequence the proportion of contained metals also varies from place to place. Therefore, a single sample taken in any particular place would not contain the same proportion of metals as does the orebody as a whole except by a highly improbable coincidence. The probable error, which would be very large if only one sample were taken, decreases with the number of samples, but it never disappears completely unless the samples are so numerous and so large that their aggregate is equal to the orebody itself, in which case the orebody would be completely used up in the process of sampling. Since carrying sampling to such an extreme would defeat its own purpose, some probable error is always present in actual cases and the practical objective is to reduce this probable error to allowable limits. This means balancing the number of samples against the desired accuracy; if there are not enough samples the result is unreliable; if there are too many, the time and expense of taking them is excessive.” (McKinstry, et al., 1948). In an actual orebody, the accuracy of sampling depends not alone on the number of samples but also on proper distribution of them throughout the orebody, for it would obviously be incorrect to take all of the samples either in a rich part or a lean part. Therefore it is important to select the places in such a way that all parts of the orebody will be represented. “For those who cultivate land which is alike arid, heavy , and barren, and in which they sow seeds, do not make so great a harvest as those who cultivate a fertile and mellow soil and sow their grain in that. And since by far the greater number of miners are unskilled rather than skilled in the art, it follows that mining is a profitable occupation to very few men, and a source of loss to many more.” (Georgius Agricola page 5 Book 1 as translated by H.C. Hoover and Lou Henry Hoover, 1950)“It is evident that mining is very profitable to those who give it care and attention”"

Jan 1, 2015

By S. Potgieter-Vermaak, T. T. Chiweshe, W. Purcell

Complete isolation of chromium (III) from the reference material (SARM 131), Upper Group 2 (UG2) chromite ore, and Merensky Reef mineral ore was achieved using ammonium phosphate salt as flux. Optimum pH (3.2–3.8) conditions and sample to flux ratios (1:25) were some of the factors that were critical for the complete isolation of chromium. Increasing the sample to flux ratio (1:50 excess) however resulted in the conversion of all the elements in the melt into a green solution (pH, 5.8–6.7). A different chromium compound was subsequently isolated from the green solution by allowing this solution to stand in an open vessel in a cupboard for a month during which time the pH decreased to pH 3.5–4.2. Quantitative analyses of chromium from the isolated precipitates of SARM 131, UG2 chromite ore, and Merensky Reef mineral ore indicated chromium contents of 41.87, 60.41, and 23.93% respectively which were very close to the chromium content in the original samples. Analysis of the chromium precipitates using IR indicated the presence of phosphates (1100–1200 cm−1 ) while SEM-EDX analysis showed the presence of microscopic crystalline particles with Cr, P, and O as the major elements. Further characterization of the chromium precipitates using XRD and Raman successfully identified the product as chromium (III) metaphosphate C-type (Cr(PO3)3, JCPDS no. 01-077-0672), in the isolated chromium precipitates.