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By Steve Kral

The mining industry is no stranger to hard times. Throughout its history, the industry has faced the ups and downs of commodity prices, difficult-to-mine-and-process ore bodies, labor issues and other problems. Throughout it all, though, the mining industry continues to provide the materials needed for society —even in the face of attacks by those who seek to cripple the industry or have it go away. The reason the mining industry survives, of course, is that mankind requires the products the industry produces. And, in recent decades, the industry has developed new technologies and improved on existing ones to produce those products in environmentally sound ways. At the same time, the economic benefits have been enormous to communities throughout the world where mining takes place.

Jan 1, 2002

By M. Mead, J. Dumouchel, W. Yule, J. Giroux

The QMM mineral sands of South East Madagascar contain approximately 1,900 million tonnes of mineable sand with a total heavy mineral (THM) content of roughly 4.5wt%. The QMM deposits are the world’s largest known reserves of 60% TiO2 ilmenite and also contain a small volume of zircon. The deposits are semi-continuous and homogenous and the mineralized sands are free flowing with minimal overburden, induration & slimes. These characteristics are favourable to dredge mining and allow the application of conventional wet gravity, electrostatic & magnetic separation to final products. A mature THM mineral suite of high valuable heavy minerals (VHM) content has enabled the development of a relatively simple separation process.

Jan 1, 2005

By Badiozamani Khosrow

Introduction The mining industry has been using computers since the late 1950s. Despite this early start, the use of mine planning software is not a common practice in many operations. But the trend might be changing because of the availability of relatively inexpensive personal computers (PC). The introduction of these machines has generated unprecedented interest by mine managers to computerize their planning operations. However, some managers have become disappointed with the PC's lack of adequate software and the inability to handle the massive amounts of information required for modeling. This paper is an attempt to shed some light on the future of computers in the mining industry. It will examine: • historical progress in the computer industry, • future advances in the computer industry, • historical usage of computers in mining, and • future alternatives available to mining. Historical Progress The computer industry has come a long way since the first full-fledged electronic digital computer Electronic Numerical Integrator And Calculator (ENIAC) was built in 1946. This machine weighed more than 27 t (30 st). It contained 19,000 vacuum tubes, occupied 139 m2 (1500 sq ft), and could perform 5000 additions per second. By contrast, today's fastest, commercially available computer is the CRAY-X. It weighs less than 5 t (6 st), has no vacuum tubes, occupies less than 9 m2 (100 sq ft), and performs over 100 million operations per second. This is an incredible advancement in less than 40 years. One person commented on the rate of advancement in the computer industry. He suggested that if the auto industry had advanced at the same rate as the electronics industry, we could buy a Rolls Royce for $2.75 and it would run

Jan 9, 1984

By Kerry Spickelmier

The only nickel smelter and the only active nickel mine in the United States is Glenbrook Nickel Co., a joint venture (50% each) of Cominco Resources International Ltd. and Cominco Ltd. In 1989, with the nickel price riding high between $2.30 and $2.70/kg ($5 and $6/lb), Glenbrook seized the opportunity to purchase and recommission a southwestern Oregon ferronickel smelter and the adjacent nickel-ore mine. This Douglas County site is only about 97 km (60 miles) due east of the Pacific Ocean, and California's border lies a similar distance to the south. Hanna Mining Co. had closed the operation in 1987. And the following year, the equipment had been largely stripped for salvage value. From November 1990 through August 1992, the mine supplied an average 5 kt/d (5500 wet stpd) of ore. Currently, with import ore supplying 40% of the smelter feed, the mine's daily tonnage averages 4.2 kt (4600 wet st). From November 1990 through August 1993, the mine has delivered 2.1 Mt (2.3 million st) of ore grading 1.22% nickel with an average moisture content of 26%. Buffaloed nickel? A nickel is not worth what it was in 1989 and neither is ferronickel, with recent prices hovering around $1.13/kg ($2.50/lb). To survive, Glenbrook has focused on increasing smelter production to lower its operating costs. And this strategy has triggered several bold moves: • a new, $30 million, port facility and • a 10-year importation contract for ore from New Caledonia, an island approximately 1000 km (625 miles) east of Australia. For a Glenbrook update, a May 25, 1993 visit was made to the company's Oregon operations - the mine and smelter near Riddle plus its new Coos Bay port facility. Unfortunately, as the rain came down that day, so did news of another temporary shutdown. The previous suspension had lasted from Dec. 20, 1992 until Feb. 22, 1993. Barely three months back to work on a wet May afternoon, more than 250 of Glenbrook's approximately 300 employees contemplated yet another shutdown, effective July 31, 1993.

Jan 1, 1993

By R. K. Sinha, B. S. Choudhary, Desh Deepak, A. K. Mishra, Hemant Agrawal, Shankar Kumar

There are several methods (empirical, statistical, and machine learning tools) to calculate blast-induced ground vibration. Still, due to complications in the blasting procedure, under varying blasting loads and strata conditions, it is not easy to predict and simulate blast vibration precisely. Therefore, a study was conducted to simulate the field blast data in Ansys software using explicit dynamics. For this study, monitoring of ground vibration for 20 single hole blasts was carried out. The density of emulsion explosives was in the range of 0.9 to 1.15 g/cc. In the laboratory, rock properties were determined from the rock sample collected from the mine site before blasting. The in-hole velocity of detonation (VoD) and the density of the emulsion explosive were also determined. These parameters were used for numerical analysis to know the ground vibrations at specified points. The results of ground vibration predicted by the model are validated using field data.

By A. L. Hornbaker

Colorado has recorded more than 100 years of industrial mineral production. Much of the state's history, culture, and economy is based in mining, but the industrial minerals and construction materials comprising the nonmetallics sector of the industry very often are overlooked or overshadowed by mineral fuels and the metals. Indeed, many of these materials find use in seemingly unimportant industrial applications essential to our economy and life style and yet are not so recognized by the consumer. Unlike many other mineral resources, the numerous industrial minerals occur in many different and often exotic geologic environments, some of which are characteristic only of the western states. In Colorado only a few of these minerals have continued production through the years; many saw only "boom" periods or other critical times of need, such as the world wars. The changing needs and demands of our society in the 1980s will stimulate yet another era of intensive activity in our industrial minerals storehouse. Researchers are finding new uses and applications for these materials in dealing with the energy crisis and fuel shortages, the need to develop domestic mineral reserves of all kinds, and the goals of reuse and recycling. Some of Colorado's little-used and unused industrial minerals hold extraordinary promise in solving some of these problems on the regional and national levels. In this paper we will look at the history of development of Colorado's more prominent nonmetallics and especially at current research on and future potential of several other commodities among which Colorado contains the largest known reserves.

Jan 1, 1980

By Kirsten Corin, Belinda McFadzean, Cyril O’Connor, Jenny Wiese

The Bushveld Complex of South Africa contains almost 90% of the world’s reserves of platinum group minerals (PGMs). In the flotation of PGMs, there are significant challenges arising from the need to treat ever-decreasing grades of the relevant ore deposits. The major challenge in the flotation of these ore bodies is the control and management of the gangue minerals, particularly silicates such as orthopyroxene, plagioclase feldspar, and pyroxene which are often rimmed with talc which makes them naturally floatable. It has been shown that various polysaccharide depressants such as CMC and guar have different properties in terms of depressing the gangue minerals. Since the PGMs are often associated with sulphides, copper sulphate is widely used as an activator in PGM flotation but can inadvertently activate the gangue minerals as well as reduce the recovery of PtTe2 which accounts for up to 40% of the Pt in the Platreef ore body. Depressants also reduce the mass of solids reporting to the froth and can thus destabilise the froth. This effect on the froth can be mitigated by using higher frother dosages or water of higher ionic strength. Reducing chromite recovery is of critical importance since high levels may negatively affect the downstream smelting process. Chromite recoveries can however be reduced through the application of gravity separation or reducing entrainment through reduced water recovery. In summary, due care needs to be taken to carry out site test work to develop an optimum ratio of collector, frother, activator, and depressant to ensure that the highest grades and recoveries of the PGEs are obtained while reducing depressant dosage as much as possible.

By Gennaro G. Marino

During the preliminary design stages of the Illinois Division of Natural Resources(DNR) building, it was discovered that an old coal mine was present some 70 m (220 ft) beneath the building site. The new DNR building to be constructed is 36 m (120 ft)wide and 134 m (440 ft) long. It has three stories above grade and abasement level. The building is oriented north-south and has east and west ponds next to it (Fig. 1). The building is located on the State Fairgrounds in Springfield, IL. Given the history of surface subsidence of these underground coal mines in the Springfield area, there was concern about the potential for future subsidence at the building site. Mine subsidence events in the area have resulted in more than 0.9 m (3 ft) of settlement and have caused significant structural damage.

Jan 1, 2000

The past four years since the 2008 MINExpo have been a roller coaster ride for the mining industry, with highs and lows and everything in between. One of the natural consequences of this uncertainty has been a number of significant consolidations and mergers, and this trend has trickled down into the crushing industry. And while there have been some significant changes to this sector of the mining industry, many of the big players have weathered the storm. The following is a look at some of the mineral processing companies that will be at MINExpo. McLanahan Corp. McLanahan Corp. is an example of the changes in the sector. The crushing and grinding stalwart acquired Universal Engineering, expanding its traditional focus on soft mineral crushing to hard rock crushing. At MINExpo, it will be showing off three new pieces of equipment, the LabMill Crusher, the Rocker Tooth Crusher and the Recessed Filter Press.

Jan 1, 2012

By L. Yuan, A. Smith

In order to provide insights for the optimization of ventilation systems for U. S. underground coal mines facing both methane control and spontaneous combustion issues, a computational fluid dynamics (CFD) study was conducted to model the potential for spontaneous heating in longwall gob areas. A two longwall panel district using a bleeder ventilation system was simulated. The permeability and porosity profiles for the longwall gob were generated from a geotechnical model and were used as inputs for the CFD modeling. In this study the effect of methane emissions from the mined coal seam, including the longwall face and overlying rider seam reservoirs on the gob gas distribution was considered. The spontaneous heating is modeled as the low-temperature oxidation of coal in the gob using kinetic data obtained from previous laboratory-scale spontaneous combustion studies. Unsteady state simulations were conducted and the effects of the coal’s apparent activation energy and reaction surface area on the spontaneous heating process were also examined. Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health.

Jan 1, 2007

By M. J. Allan, D. J. Barratt

This paper reviews current testing methods for sizing autogenom and semiautogenom mills in the North American context with comments on the necessity for test work and requirements for different circuits and equipment selection. The economics of testing and the value received are discussed.

Jan 1, 1987

By M. K. Larson, J. K. Whyatt

Proper employment of numerical stress analysis design tools is based on the demonstrated ability of a model to capture key elements of the geologic site model and accurately simulate how these elements interact with a mine design. While these tools have progressed markedly, they are, at heart, a gross simplification of the abundant complexity of a natural setting and its response to mining. A generic deep longwall site model was developed that includes aspects of the geology of deep coal mines in the Wasatch Plateau and Book Cliffs coal fields of Utah. The site model contains a set of common features and observations of how these features typically respond to mining. This site model was the basis for evaluating use of empirical, boundary element and volume element stress analysis tools to analyze the distribution of stress around a deep longwall panel. More specifically, this evaluation examined shifting of stress to panel abutments and gob, distribution of stress in the abutment and deformation and failure of bridging strata. Measurements of abutment stress changes at two sites in the Wasatch Plateau region were used to illustrate model calibration. Overall, these comparisons highlight the considerable differences between methods. Volume element tools can incorporate considerable detail and have fewer underlying assumptions, but this detail carries a considerable computational cost. Boundary element tools are much more efficient. However, this efficiency comes at the cost of added assumptions. These assumptions were challenged by the presence of a strong sandstone unit in the overburden, leading to boundary element results that depart significantly from volume element results. Empirical rules are the simplest, but are even more burdened by assumptions, many of which are implicit in underlying cases. Insight into the nature and impact of underlying assumptions in each method is essential to the proper use of results in mine design.

Jan 1, 2009

The development of information concerning mesothelioma in South Africa started with the 1959 finding of Dr. J. Christopher Wagner of cases of mesothelioma in persons living in the vicinity or working in crocidolite mines in Cape Province. After more than 40 years, the data from South Africa now provide important insights into the differences in mesothelioma risk associated with different asbestos fiber-types. Three case series reports and one analytical report were reviewed in this session. In total, information on 504 proven cases was presented. There were 28% of cases arising from occupational exposure in mining, 35% from non-mining occupations, 23% from environmental exposures; 14% where no exposure was established and 9% where the exposure was unknown. Among the 129 cases for which occupational exposure and asbestos fiber-type were established, 115 cases were associated with occupational exposure to Cape crocidolite; 1 case associated with occupational exposure to Transvaal crocidolite and 9 cases with occupational exposure to amosite (grunerite asbestos) and 4 cases with occupational exposure to mixed fiber-types. There were no cases associated with chrysotile asbestos. There were 33 cases of environmental mesothelioma linked to Cape crocidolite exposure and 2 to exposure to amosite and crocidolite but none to Transvaal amosite alone or to chrysotile. The evidence shows that amosite is capable of causing mesothelioma but that the major risk in South Africa is associated with Cape crocidolite.

Jan 1, 2008

Sustainable development is at odds with reality in the minerals industry. Increasing world population and aspirations are leading to increased energy and mineral consumption. Non-renewable fossil fuels are being exploited at a much faster rate than they are being discovered. Mineral reserves are diminishing and of lower grade. Despite recycling, many of the economic reserves of the rarer metals on which technological society has come to depend are being depleted, and many of the bulk metals are being exploited at ever increasing rates. And yet, mining continues, with a long-term downtrend in commodity prices, matched by more efficient mining and processing. Will society turn to a low carbon economy before fossil fuels are depleted? Will prices come to better reflect the full cost of mineral production? Will technology save us, or is it at the root of the problem? The key drivers continue to be an ever increasing aspirational population and the law of supply and demand, rather than sustainability considerations. The paper illustrates this with examples of worldwide and Australian data.

Jan 1, 2011

By L. E. Mercando

The proposed Flambeau Mining Project is based on a high grade copper deposit located approximately one mile southwest of Ladysmith, Wisconsin. The project involves only the mining, crushing, and shipping of ore to facilities outside of Wisconsin for processing. The Wisconsin environmental regulations include provisions for identifying wetlands, the requirements for minimizing the disturbance of wetlands, and the need to establish new wet-lands to replace any wetlands which have to be disturbed.

Jan 1, 1991

By Carmel Bofinger, Maureen E. Hassall, David Cliff, Eric Stemn

e Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

By Carmel Bofinger, Maureen E. Hassall, David Cliff, Eric Stemn

e Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Many states rely upon the Pennsylvania 1957 “Gas Well Pillar Study” to evaluate the coal barrier surrounding gas wells (Commonwealth of Pennsylvania, 1957). The study included 77 gas well failure cases that occurred in the Pittsburgh and Freeport coal seams over a 25-year span. At the time, coal was mined using the room-and-pillar mining method with full or partial pillar recovery, and square or rectangle pillars surrounding the gas wells were left to protect the wells. The study provided guidelines for pillar sizes under different overburden depths up to 700 ft. The 1957 study has also been used to determine gas well pillar sizes in longwall mines since longwall mining began in the 1970s. The original study was developed for room-and-pillar mining and could be applied to gas wells in longwall chain pillars under shallow cover. However, under deep cover, severe deformations in gas wells have occurred in longwall chain pillars. Presently, with a better understanding of coal pillar mechanics, new insight into subsidence movements induced by retreat mining, and advances in numerical modeling, it has become both critically important and feasible to evaluate the adequacy of the 1957 study for longwall gas well pillars. In this paper, the data from the 1957 study is analyzed from a new perspective by considering various factors, including overburden depth, failure location, failure time, pillar safety factor (SF), and floor pressure. The pillar SF and floor pressure are calculated by considering abutment pressure induced by full pillar recovery. A statistical analysis is performed to find correlations between various factors and helps identify the most significant factors for the stability of gas wells influenced by retreat mining. Through analyzing the data from the 1957 study, the guidelines for gas well pillars in the 1957 study are evaluated for their adequacy for room-and-pillar mining and their applicability to longwall mining. Numerical modeling is used to model the stability of gas wells by quantifying the mining-induced stresses in gas well casings. Results of this study indicate that the guidelines in the 1957 study may be appropriate for pillars protecting conventional gas wells in both room-and-pillar mining and longwall mining under overburden depths up to 700 ft but may not be sufficient for protective pillars under deep cover. The current evaluation of the 1957 study provides not only insights about potential gas well failures caused by retreat mining but also implications for what critical considerations should be considered to protect gas wells in longwall mining.

Jul 28, 2020

By X. Tang, N. Ripepi

The Langmuir model has been widely used for the coal-methane sorption process through an isothermal test. However, even though the temperature-dependent Langmuir model was recognized theoretically and experimentally, the quantitative relationships between the Langmuir constants a and b and temperature have not been clarified and confirmed by laboratory test data. This paper collects 158 methane-coal sorption data under different temperatures that apply the Langmuir model to the relationships between the Langmuir constants a and b and temperature. Even though the Langmuir model cannot be used to show the physical state of methane adsorption on coal, it is widely used because of its simplicity and the reasonable explanation of its parameters a and b. The results from these published isothermal tests indicate that (1) there is no consistent relationship between Langmuir constant a and temperature, (2) the Langmuir model is a temperature-dependent model whose temperature-dependent feature is mainly shown by the relationship between the Langmuir constant b and temperature, and (3) the relationship between the Langmuir constant b and temperature can be described by both exponential and linear relationships with dried coal. This paper provides a database for the temperature-dependent Langmuir model that can be used for the reservoir simulation of coalbed methane reservoirs and for the coal seam degasification modeling of underground coal mines, considering the heating effects induced by geothermal and heat injection through factors such as hot water, hot steam and ultrasonics.

Jan 1, 2016

By S. E. Phillipson

During the course of evaluations by the Mine Safety and Health Administration’s Roof Control Division, the controls on ground instability were investigated at surface and underground limestone mines throughout the eastern and southern United States. Structural geologic features, including joints and faults, were identified by basic geologic mapping as primary controls on highwall and back instability in surface and underground limestone mines. By comparing the spatial orientation of discontinuities and internal angle of friction with the orientation of highwalls on a stereonet, the potential for sliding, toppling, and raveling failures was evaluated in a semi-quantitative fashion. Structural geologic mapping identified faults and joints, which dismembered the back and were associated with ground instability, in underground mines. This paper documents the importance of recognizing structural geologic controls on ground stability in limestone mines, advocates basic geologic mapping as a critical component of ground control programs at surface and underground limestone mines, and provides examples of simple stability evaluations using the stereonet method.

Jan 1, 2006