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By J. A. Marts, R. C. Gilmore, Jr. Bogin, S. A. Saki, J. F. Brune, J. W. Grubb

"Most, if not all longwall gobs contain explosive gas zones (EGZs), i.e., zones of explosive methane-air mixtures that can cause – and have caused – mine fires and explosions. If the coal is prone to spontaneous combustion, oxygen penetration into the gob must be avoided. This paper summarizes the significant research findings from five years of computational fluid dynamics (CFD) modeling research conducted at the Colorado School of Mines (CSM) under funding from the National Institute for Occupational Safety and Health (NIOSH). CSM Researchers have developed CFD modeling techniques to identify where and under what circumstances EGZs can form in longwall gobs and how EGZ formation and oxygen penetration depend on the ventilation method, face and bleeder ventilation parameters, injection of inert gases and the operation of gob ventilation boreholes. Recognizing these explosion and fire hazards is an important first step in improving the safety of longwall coal mines. CSM modeling research has shown that EGZ formation can be effectively controlled by adjusting ventilation parameters, choosing the proper ventilation pattern and injecting inert gases where necessary. INTRODUCTION In a project sponsored by the NIOSH Office of Mine Safety and Health Research, researchers at the Colorado School of Mines have examined gas compositions and flows in longwall gobs in order to assess explosion and fire hazards. Since gob areas are inaccessible, researchers developed a series of computational fluid dynamics (CFD) numerical modeling tools to characterize these hazards. A variety of CFD models were developed to cover progressively sealed as well as bleeder ventilated gobs for both coal and trona mines. The explosion and fire hazards posed by EGZs in longwall gobs can be summarized as follows.• If the EGZ lies closely behind the longwall face, flames and pressures from an explosion can penetrate the shield supports and reach the active face area, creating blast trauma, burn hazards and toxic, unbreathable atmospheres. • EGZs can be pushed around inside the gob by roof collapses and cave-ins. If they get pushed out into the face area, sudden methane inundations and explosion hazards in face areas can result. • Fresh air flowing into the gob can create an explosion hazard as the gas composition in the gob moves from fuel-rich inert to explosive, creating EGZs. • Ignition sources inside the gob can be frictional ignitions or spontaneous combustion. • Bleeder ventilated gobs are surrounded on all sides by an EGZ that forms along the fringe areas between the fresh-air ventilated bleeder entries and the methane-rich interior of the gob. It is suspected that diffusion flames can propagate rapidly along these EGZ fringes if an ignition occurs"

Jan 1, 2015

By Patricia Pride, Kurt Bettger, Jack Raymer

"INTRODUCTION The Jefferson Barracks Tunnel is in the final stages of design and is expected to go out to bid in the summer of 2016. The project is located in south St. Louis County along the west bank of the Mississippi River, about 13 km downstream of the St. Louis Gateway Arch. The project consists of a deep sanitary sewer tunnel, a deep pump station and several intakes. The intakes will divert sanitary flows into the tunnel and the tunnel will convey the flows by gravity to the Lemay No. 3 Pump Station, which will pump them up into the Lemay Waste Water Treatment Plant. The tunnel is about 5.4 km long and will be lined with 84-inch (2.1 m) fiberglass pipe. It drops at a gradient of 0.1 percent from south to north and will be bored through strong limestone using a hard-rock tunnel boring machine (TBM). The diameter of the TBM is anticipated to be about 3.4 m. The Owner’s original concept was for a relatively shallow tunnel so as to minimize construction and pumping costs. The preferred alignment ran close to the river, next to the existing force main, which was to be abandoned. Keeping the tunnel close to the force main would reduce the amount of shallow sewer work needed to connect the existing feeder sewers to the new tunnel. Several geotechnical investigations were performed, with shallowly focused geophysics and the borings all going exactly down the conceptual tunnel depth. Limestone bluffs run along the Missouri side of the river. These bluffs are pockmarked by sinkholes and riddled with karst. Large, well-known caves occur both north and south of the alignment. Karst features, including deep crevices and possible caves, were found in those early geotechnical investigations. Many of these features extended well below the level of the Mississippi River and would have been encountered by the tunnel. If a large crevice or cave were encountered, then the inflow of mud and water into the tunnel could have been large and possibly uncontrollable. Something had to be done to mitigate this situation. Pre-excavation grouting was considered, but the program would have been huge and extremely expensive. Using a closed-face TBM with bolted and gasketed lining was also considered, but that too was both risky and extremely expensive. The Owner could have abandoned the tunnel altogether and built a new force main, but that would have brought a whole new set of problems and was undesirable to the Owner. The last option was to move the tunnel away from the karst."

Jan 1, 2016

By Michael M. Carroll, Zhu-ping Duan, Han-ping Chin

INTRODUCTION The inelastic stress-strain behavior of rocks has urged engineers to seek for the possible application of plasticity to engineering pro¬jects such as tunnels, oil wells, dams, etc. for a long time. Early efforts in this direction have tentatively used the classical theories to solve some axisymmetric problems, in which the rocks were treated as perfectly plastic and nonfrictional materials (Talobre, J. A., 1957). Meanwhile, one of the fundamental assumptions is that the volume strain of elastoplastic material is purely elastic. Drucker and Prager (1952) developed a perfectly plastic and frictional model with a generalized form of Mohr-Coulomb law, which serves as both failure criterion and yield criterion. Although the associated flow rule gives unacceptably large dilatancy, this model is a very important step to deal with the frictional behavior of geological materials. As a further step, Roscoe et al (1963) and Schofield and Wroth (1968) proposed a Cam-clay model, which accounts for the yielding before the material reaches a failure envelope and reflects the plastic volume strain as a strain hardening factor, and the open end of the Drucker-Prager envelope is capped by a family of yield surfaces, the envelope is made conforming with crit¬ical void ratio line. The proposed shapes of the cap have been based on experimental data and on convenience of mathematical descrip¬tions. Drucker, Gibson and Henkel (1957) introduced a spherical cap for soils, while in Cam-clay model the cap is semi-logarithmic yield function derived from the result of triaxial tests. DiMaggio and Sandler (1971) proposed an elliptical model for sand, in which the hardening function depends exponentially on plastic strain. Sandler et al (1976) used a plane cap model to express the behavior of a wide range of geological materials of which the nonlinear hysteretic nature is significant. Mizuno and Chen (1982) illustrated the physical mean¬ing of cap models and their adaption to finite element calculation. In recent years, Carroll et al (1972, 1980) have studied the com¬paction of porous materials under hydrostatic pressure and discussed the mechanism of the nonlinear response thoroughly. Analytical and numerical analysis of the hollow sphere model by Curran and Carroll (1979) predicted an initial yielding surface, dependent on the initial porosity, and showed a strong coupling between hydrostatic and deviatoric effects. All these main features from the abovementioned theoretical research are visualized by the experimental data on Boise sandstone (1984). The combination of such previous work would be logically the construction of a plasticity model for porous rocks which, following the tradition of assigning the name of birthplace to a special model, is called Cal-Rock model (Carrol, M. M., 1984). The results of triaxial tests along different loading paths reveal the compaction characteristics for deviatoric and hydrostatic stress separately. the fitting of the nonlinear stress-strain curves leads to a construction of yield surfaces. Moreover, an uniaxial strain test gives the strength envelope which is the critical state line. The whole model is composed in the frame of elasticity theory. The concept and representation of plasticity used here are in the spirit of Naghdi¬Casey theory (Casey and Naghdi, 1984 and 1984, Naghdi and Trapp, 1975). In order to find the way of using such a plasticity model in engineering problems, the stress field in a thick-walled cylinder of porous material is calculated. This is an axisymmetrical problem with plane strain, which is an idealization of oil well in an infinite medium. Because the constitutive relation is highly nonlinear, a numerical method has been utilized to obtain the solution. CONSTRUCTION OF CAL-ROCK MODEL (1). Elastic-plastic constitutive equations The basic assumption is that the yield surface in stress space depends on one parameter, namely the plastic volume strain, as the data on Boise sandstone suggested. Starting from this point, the theory formulated in stress space and in strain space by Naghdi and his co-workers (1975, 1981) can be simplified. The simplified yield function is

Jan 1, 1986

By JOHN HOMER, KATHLEEN STABRYLA, JACOB L. CARR, JONATHAN K. HRICA, JENNICA L. BELLANCA

Given the recent focus on powered haulage incidents within the U.S. mining sector, an appraisal of collision avoidance/warning systems (CXSs) through the lens of the research literature is timely. This paper aims to evaluate the maturity of CXS technology through the application of a technology readiness assessment (TRA) to research literature identified by systematic search methods. Results indicate that much of the evidence for CXS performance is at lower levels of maturity: that is, components and prototypes tested in a laboratory and in relevant environments. Less evidence exists for CXS performance at higher levels of maturity — that is, systems evaluated within operational environments — despite the existence of commercial products in the marketplace. This lack of evidence at higher maturity levels within the scientific literature highlights the need for more peer-reviewed research to evaluate CXS technologies. Additionally, results of the review reveal that most of the literature relevant to CXS technologies is focused on vehicle-to-vehicle interactions, which contrasts with haul truck fatal accident statistics that indicate most are due to vehicle-to-environment interactions, such as traveling through a berm. Lastly, the relatively small number and segmented nature of relevant studies suggest there is a need for more incremental research that would better facilitate the improvement of CXS technologies. This progression could be achieved through continued long-term interest and support for CXS technology research.

Mar 1, 2023

By Nellie E. Guernsey, Louis J. Sousa, Alfred Weiss, Nickolas J. Themelis

Over the past decade, numerous factors have led US copper firms to face increasingly severe competition from low cost foreign producers. As a result, greater attention is being devoted to developing and implementing new technology that can reduce costs and maintain the competitive position of domestic firms while simultaneously meeting environmental requirements. To obtain a better understanding of the likelihood of the development, adoption, and use of innovative copper technologies in the future, the Bureau of Mines contracted with Mineral Systems Inc. of Stamford, CT, to undertake a systematic survey of technological experts in industry, government, and the academic community. According to the survey, major developments in exploration over the next 25 years are likely to be in technologies that facilitate analysis and interpretation of deposit data rather than those that enable the collection of additional data. Most new copper mining and beneficiation technologies are likely to represent evolutionary extensions of existing systems with a notable increase expected in the application of information systems technologies and computer control methods. A possible movement towards increased usage of continuous mining systems in copper was also noted. Experts indicated that several copper smelters are under consideration for extensive renovation and, as a result, flash smelting technology is expected to become much more widely used in the US. A gradual movement toward continuous smelting methods was also forecast. In copper refining, the major technological change expected is the gradual automation of various refinery operations. Finally, though increased usage is expected, in situ solution mining and hydrometallurgical processing of sulfide ores are not expected to become widespread over the forecast time horizon. This first article in a two-part series describes the survey method chosen and the technological innovations selected for eval¬uation. Also discussed are the assessment panels, background scenarios, critical events, and diffusion forecasts. Next month, part two will address technology forecasts resulting from the study. Featured are discussions on future copper exploration, mining, beneficiation, smelting, refining, and recycling. A cost/benefit analysis will also be included. Methodology Selection of Assessment Method To develop a consensus forecast of technological change in the copper industry, a technique for systematically polling subjective opinions of experts was required. After conducting a literature survey and some preliminary testing, the direct probability assessment method was selected. With this assessment method experts are asked to express in quantitative terms their judgment of the probability that a specified event will occur, usually over a series of time frames. The method was chosen because the experts were observed to be more comfortable with this approach during the testing period, and the results of this process effectively satisfied the assessment objective. The experts generally could provide more precise estimates of the timing of future events using this technique because it was the least cumbersome of the assessment methods tested. Identification, Selection, and Description of the Technologies The initial list (Table 1) of innovative copper technologies assessed in the study was developed from two principal sources: knowledge and expertise of the study team and a review of relevant technical literature. From this list of 47 potential technologies, 10 were selected for detailed assessment. Table 2 lists 35 technologies that were subsequently identified in the first series of assessments. Twelve technologies from this list were also selected for detailed evaluation in a second assessment round. Criteria used for the final selection of technologies for detailed assessment specified that: • The expected impact of each technology on copper supply (i.e.,

Jan 9, 1983

By G. G. Marino, Z. R. Widup

Marino Engineering Associates, Inc. (MEA) was asked to determine the effects of mining beneath a proposed roadway structure. In order to determine the subsidence potential and the magnitude of the mine stabilization costs it is important to know whether underground mining is present, and if so, to what a real extent. The site investigated had the potential to have mining in three different coal seams. To determine where mining was present MEAÕs borehole radar system was used. In summary, the borehole radar subsurface investigation validated that the available mine map in the most shallow coal seam was fairly accurate despite its age (1888), found no mining in the underlying coal seam and detected an area of unknown mining at a depth of about 300 ft in the lowest coal seam which was verified by subsequent drilling.

Jan 1, 2004

By M. E. Lewellyn

A new class of thionocarbamates, O-alkyl-N-allyl thionocarbamate (III), has been found to give better metallurgy than 0-isopropyl-N-ethyl thionocarbamate (I) for a number of sulfide ores containing copper, lead, and zinc. Data on the results of flotation tests with several such ores are presented. The improved metallurgy is believed to be due to the participation of the allyl double bond in the complex formation of the thionocarbamate on the surface of the mineral.

Jan 1, 1985

By Russell C. Drew

The United States has long been recognized for its ability to marshall the many tools of its scientists and engineers to meet national threats or crises. Two major World Wars, the Dust Bowl, the Soviet Missile threat, Sputnik, and more recently the Energy Crisis have stimulated military weapons development, massive land reclamation and water management programs, NASA, and the Space Program, Project Independence, and soon a new agency, the Energy Research and Development Administration. While our record of successful responses to these major national concerns lends support to the expectation that we will succeed in dealing with the current energy problem and potential future crises as well, the crisis mode of response is becoming increasingly wasteful of funds and human and natural resources. This waste, while always of a concern, is a more important factor than previously because of the accelerating pace at which the world has been shrinking, relatively, in comparison to its human population and that population's increasing demand for resources, both renewable and nonrenewable. If present growth patterns continue, in the year 2000 there will be two people to feed, clothe, house, and satisfy for every one person that existed in 1970. On a finite planet, with finite land areas, limited resources, and only partial understanding of the means by which future problems can be addressed, one of the major threats to mankind will be scarcity and one of our major challenges will be better management of our resources. The challenge will be to guide Federal investments in R&D that are of sufficient magnitude and in the proper

Jan 1, 1974

By Georgios Bartzas, Vasiliki Karmali, Konstantinos Komnitsas, Anna Kritikaki, Dimitra Vathi, Stylianos Tampouris, Arne Peys

Large volumes of slags, with varying mineralogical and geochemical characteristics, are produced annually by the ferrous and nonferrous metallurgical industry. Most of them are considered as potential secondary resources and may be valorized, following the principles of circular economy, for the recovery of critical elements, including energy transition metals. Apart from the economic benefits, valorization of slags may contribute to the competitiveness of the metal industry and the conservation of natural resources. Valorization also results in minimization of environmental impacts on soils and waters in slag disposal areas, due to the prevention of solubilization and subsequent migration of potentially hazardous elements. The present study utilizes ferronickel (FeNi) slag for the production of alkali-activated materials. The effects of the main experimental parameters, including sodium hydroxide (NaOH) molarity, silica/sodium oxide (SiO2 /Na2O) molar ratio in the activating solution, precuring and curing time, curing temperature and aging period on several properties of the final products, are assessed.

Apr 1, 2025

By Ying Lu, Jeffrey C. Johnson, Chen-Luh Lin, Jan D. Miller, Sindhoora Puvvada

The amount of energy used to break rock is of interest in mine-to-mill operations to minimize energy consumption during blasting at the mine site and comminution at the processing plant. In this research, a direct energy measurement was made using high-velocity impact to cause breakage of long granite cores, and to study the energy dissipation along the entire bar length. The results show the formation of three zones of damage — fragmentation, fracture and elastic — that have been characterized in 3D using X-ray tomography. The fragmentation zone of the granite bars was studied in detail to describe the particle size distribution and the particle shape characteristics. The experimental energy dissipation in the fragmentation zone was found to be in close agreement with the expected energy calculated from the Bond work index (BWI) equation [1] when the anisotropic granite particles in the fragmentation zone are defined by length rather than by sieve size. The results increase our understanding of rock breakage and energy consumption and may find future applications in mine-to-mill operations.

By Colin J. Douch

New Zealand has been a significant producer of gold for over a century. Total recorded production is over 850 tonnes. There were three major periods of production: the first and biggest was between 1860 and 1880, the second was between 1895 and 1920 and the third was between 1930 and 1945. After 1945 gold production fell continually until 1980 when the major upward adjustment in gold price led to renewed interest. There have been important new developments in each of the known gold-rich areas: Westland, Otago and Coromandel and exploration for gold in these areas and in previously unprospected regions has reached unprecedented levels. In Westland over 140 gold processing plants are each producing between two and six ounces a day from low-grade placers. A major gold dredging operation will soon be producing over a tonne of gold annually and other new dredges are proposed. There are still vast reserves of gold-bearing gravels in Westland and prospecting is continuing to reveal new resources. In the Reefton area there is renewed interest in gold-bearing quartz reefs which were the source of over a million ounces of gold between 1900 and 1951. New large opencast reserves are now defined.

Jan 1, 1988

By Wallace W. Wilson

It scarcely 1s possible to read a new issue of any of the principal mining trade journals without noting some mention of a major new overseas mining venture with which one or more domestic companies are involved. These projects seem to follow a fairly consistant pattern; most are large open pit mines, with relatively low grade ore bodies but huge reserves; the total price tag will be in nine significant figures and around half or more of the total cost will be for infrastructure. West1 noted that nearly $7 billion is being invested annually for new mining projects and the expansion of existing mining ventures, in the free world. He anticipates that by the year 1975 such investments would reach the $10-11 billion annual figure, and that in the five year period 1972-76 total capital requirements can be expected to aggregate around $45 billion. The proportion of this total investment which will be financed in some manner is difficult to estimate because of the variety of available financing arrangements. West estimated that around 75% of the total capital would come from internally generated funds, with the balance from external sources. Conceivably a substantially higher percentage could be attributable to external financing, especially it the trend of recent mineral development in Canada and Australia is any criterion, and of course, including local sales of equity as a part of the package.

Jan 1, 1973

By S. Horton, F. L. Stanley, P. J. Bethell

Introduction The McClure River Processing Plant is located at McClure in Dickenson County, VA. The plant was originally constructed in 1979 as a 600 st per hour facility. The plant is fed by coals from numerous mines in the area as well as a major longwall mine onsite. Coal is processed predominantly for the metallurgical coal market. The original plant was comprised of three separate processing circuits incorporating a heavy medium vessel for the coarse material (+10 mm). Intermediate sized material (10 x 0.6 mm) was beneficiated in heavy medium cyclones, with the remaining fines (0.6 mm x 0) passing to froth flotation for upgrading. The products from all three circuits were combined prior to thermal drying and then stored in silos or ground storage prior to shipment to the metallurgical coal markets. A middlings heavy medium cyclone circuit was also present to rewash the vessel and primary heavy medium cyclone rejects. The original circuit is as shown as Fig. 1 (Editor's note: All figures are reproduced at the end of this paper.) In reasonably close proximity to the McClure Plant is the much older, less efficient Moss 1 Plant, (Chance cone, table, water only cyclone, froth flotation, Fig. 2), which prior to the McClure Plant expansion was processing considerable tonnages of coal. At that time, the McClure River Plant was processing coal at the maximum possible feed rate, and the Moss 1 Plant was finding increasing difficulty in maintaining the stringent quality specifications on its major metallurgical coal accounts. Given the fact that many of the feeder coals to Moss 1 could be moved with minimal difficulty and cost to McClure, an exercise was conducted to evaluate the potential of expanding the McClure Plant. This would result in transferring coals from Moss 1, thereby increasing yield, reducing operating costs, and enabling customer specifications to be met more easily. After evaluating many possible ways of expanding the McClure Plant, we eventually settled on an approach based on the idea of Gallagher at German Creek in Australia (Gallagher, 1986). Our objective was to increase plant capacity by removing the coarser size fractions (0.60 x 0.15 mm) from froth flotation and at the same time eliminating the finer fractions (1.25 x 0.6 mm) from the heavy medium cyclone circuit, thereby allowing these circuits and therefore the plant as a whole to increase its capacity. These size fractions (0.60 x 0.15 mm from froth flotation and 1.25 x 0.6 mm from the heavy medium cyclone circuit) would be treated in a new spiral circuit. After desired evaluation of the various circuit capacities, including desliming screen, clean coal filter and thermal dryer capacities, etc., it was concluded that we should be able to maintain high levels of processing efficiency in the existing circuitry while at the same time expanding plant feed rate from a nominal 600 st per hour to 1000 st per hour, thereby achieving the objectives The circuit that was finally settled on is shown in Fig. 2. Several unique features were incorporated in this circuit in an attempt to maximize processing efficiency and reduce maintenance costs. First, the idea of a single-stage spiral circuit was abandoned in favor of a two-stage circuit incorporating rewashing the primary spiral middlings in a secondary spiral (Bethell, 88). The spirals selected were Mineral Deposits Model LD4 units. It was felt, after much previous testing, that spiral middlings rather than being a true middling gravity fraction were in fact a combination of true middlings with a preponderance of misplaced light coal and high-density rock. Consequently the insertion of this material directly into either clean coal or refuse streams (per normal practice) would only lead to loss of efficiency. The operating philosophy behind the design of the circuit was to produce the purest coal and rejects possible by adjusting the spiral splitters. Misplacement of refuse into the clean coal and vice versa would be minimized by taking a fairly large middlings cut. By reprocessing this material (10%-15% of primary spiral feed) in a secondary bank of spirals the misplaced material in the primary middlings would be reprocessed and its probability of reporting to the correct stream greatly enhanced. To minimize fines loading on the spirals, fine aperture sieve bends were to be included. A further novel feature of the circuitry is the desliming/ dewatering system. A philosophy of accepting inefficiency but forcing it to work in our favor was developed. The dewatering screens (Linatex Combis) were chosen not for their ultimate screening efficiency but for their ability to remove slimes (tolerating a fair quantity of oversize in the effluent) and their enhanced maintenance characteristics. Any oversize passing into the effluent, together with the fine coal centrifuge effluent, would pass to classifying cyclones, the objective of which was to reject to overflow (and hence froth flotation) as many fines as possible (-150 µm) without running the risk of losing coarse (1.25 x 0.15 mm) material to oversize. Hence, by a process of producing a "slime free" screen product coupled with a "coarse free" cyclone overflow, sizing efficiency could be maximized. Obviously, recirculating load had to be factored into the Combi Screen design capacity. The spiral circuit as shown in Fig. 2 was installed at McClure River in January 1988. The spiral circuit efficiency was very high immediately, and, after the normal debugging, plant capacity has been increased to the point at which we are currently processing of the order of 1100 st per hour. Test program The performance of the spiral circuit has been evaluated by two major samplings of the entire new circuit, coupled with routine bi-monthly tests on all other major components of the plant circuitry.

Jan 1, 1992

By Chaoxun Zhao, TAIYOU LI, JIAQI JIN, Chen-Luh Lin, Jan D. Miller

A large portion of the energy consumed in copper concentrators is used to reduce the particle size of the feed by crushing and grinding. The cost of metal production could be reduced if low-grade particles of centimeter size were removed prior to further processing. Two copper sulfide ore samples (3 × 1 cm) from Arizona were analyzed by micro X-ray computed tomography (Micro-XCT) to determine the grade of copper sulfide in each particle. For copper ore sample A, a significant number of particles contained very low amounts of copper, while some particles had copper sulfide grains of millimeter size. Based on Micro-XCT, it was expected that 85 percent of copper for sample A could be recovered at 65 percent of mass rejection during preconcentration by sorting. However, in sample B (a different copper ore), distribution of copper sulfide was dispersed primarily in each ore particle, so for the particle size class of 3 × 1 cm, liberation of copper sulfide and gangue minerals was not significant. In view of the XCT results, dual-energy X-ray radiography was used as a basis for sorting. Pilot-scale X-ray sorting of sample A (10 × 1 cm) showed 31 percent rejection of a 0.08 percent Cu gangue product with a corresponding recovery of 90 percent copper.

By Sukumar Bandopadhyay

In recent years, research in the field of artificial intelligence (AI) has had many important successes. Among the most significant of these has been the development of powerful new computer software known as the "expert systems". Expert system programs designed to provide expert-level consultative advice in mineral exploration (Duda et al, 1981), scientific (Feigenbaum, Buchanan and Lederburg, 1971) and medical (Shortliffe, 1976) problem solving are generally acknowledged to be among the forerunners of this research. As the decision makers virtually in all fields face a more complex and involved world within which to operate, the need for some decision support is also becoming urgent. Thus applications of expert systems continue to spread out reaching problems that, because of their dimensions or particular aspects, set more demand on the decision methodologies. To meet these new requirements, many activities which were performed in the past by the domain expert or engineer must become automated. Furthermore, previous research (Dawes and Corrigan, 1974; Dawes, 1979) has shown that automating an expert's decision rules often provide better decision than the expert does. For large systems it would be very useful (or even necessary) to have formal tools, allowing one for example, to automatically discover inconsistencies, contradictions or redundancies, or to identify the possibilities of wrong lines of reasoning in the decision process.

Jan 1, 1990

By Clayton J. Parr

Introduction This chapter contains brief discussions of various environmental protection requirements that relate to underground mining operations. Environmental disturbances at an underground mining operation can result from subsidence; water discharges; waste dumps; construction and operation of access roads and utility lines; construction and operation of surface facilities such as maintenance shops, bathhouses, and storage yards; and emanation of dust and noise from surface crushers. Construction and operation of a concentrator or washing plant may result in the emission of air pollutants, the discharge of water pollutants, the creation of noise, and disturbance of the surface. Tailings ponds can be the source of fugitive dust.1 This chapter is not intended to provide a detailed discussion and analysis of laws and regulations dealing with environmental protection. Rather, its purpose is to provide the engineer with a basic awareness of the existence and nature of such laws and regulations, as well as the procedural requirements that must be followed in complying with them. The body of law relating to environmental protection has grow" very rapidly and should continue to do to for some time. Because many of the laws have been enacted recently, numerous court decisions are being rendered to resolve disputes over their interpretation. Hence, the reader is cautioned to be alert for subsequent modifications of statutes and regulations, and new case law. Rules and regulations pertaining to environmental protection are implemented at all governmental levels. The most widely known laws are those enacted by the federal government that have nationwide applicability. However, separate requirements exist in each state, county, and municipality. Because of their general applicability, federal laws are discussed most extensively in this chapter. Ownership of the property is the most significant factor considered in ascertaining what rules govern the conduct of an operation thereon. If the land is held under lease, reference to the lease terms must be made in the first instance to determine what obligations must be met in order to prevent default and possible loss of the property. If the land is held under a lease from the federal government, the operator is subject not only to compliance with the lease terms, but also to a large body of laws and administrative regulations that pertain generally to the conduct of mining operations on land held under federal leases. Although operations on unpatented mining claims, the legal title to which remains in the federal government, are not subject to the same rules and regulations that are applicable to operations conducted pursuant to federal leases or permits, they soon will be governed by a special set of regulations that provide for protection of surface resource.2 Operations conducted on lands leased from a state usually are subject to numerous environmental protection requirements specified in the lease terms, in addition to rules and regulations promulgated by the state agency having jurisdiction over mining on state lands. Operations conducted on privately held lands are subject to fewer such requirements. Leases from private parties sometimes have environmental protection and reclamation requirements written into them, but generally to a far lesser extent than governmental leases. Operations conducted on properties owned by the operator are subject only to those laws and regulations that have general applicability without regard to land ownership. COAL SURFACE MINING CONTROL AND RECLAMATION ACT OF 1977 Introduction On Aug. 3, 1977, the Federal Surface Mining Control and Reclamation Act of 1977 was signed into law.3 It governs coal-mine operations on private lands, as well as on public lands. The Act is pervasive in its scope and is extremely long and complex. The basic purpose of the Act is to control and minimize the environmental effects of surface coal mining. Surface coal-mining operations are defined as activities conducted on the surface of lands in connection with a surface coal mine and surface impacts incident to an underground coal mine.4 The Act is administered by the Secretary of the Interior through a new agency named the Office of Surface Mining Reclamation and Enforcement.5 The Act contains detailed environmental protection standards and reclamation requirements, and it establishes a permit system for all surface coal-mining operations. Mining in certain areas and under ceri-in conditions is restricted or prohibited, and a mechanism for enforcement by the states is provided. Stiff penalties are provided in the event of noncompliance. Implementation Schedule Nonfederal Lands: As required by Section 501 of the Act, interim regulations setting mining and reclamation performance standards based on and incorporating standards set out in Section 502(c) were adopted effective Dec. 13, 1977.6 They will. be incorporated as amendments to Chapter VII of Title 30, Code of Federal Regulations. Permanent regulatory procedures for surface coal-mining and reclamation operations performance standards, which were directed to be promulgated by Aug. 3, 1978, were published in proposed form on Sept. 10, 1978. 7 They govern surface coal-mining operations in any state until a permanent state or federal program is adopted. As of Feb. 3, 1978, all new operations, and as of May 3, 1978, all existing surface coal-mining operations, on lands on which such operations are regulated by a

Jan 1, 1982

By Bryan Ulrich

On March 20, 2014, the ?Roundtable Discussion on Innovations in Heap Leaching and Mine Waste Management? was hosted by Knight Piésold and Co. at the Red Lion Hotel in Elko, NV. This topic is timely, and formed something of a lead into the inaugural ?Workshop on Innovations in Waste Rock, Tails and Heap Leach Management.? That workshop, which grew from the 2013 Elko Roundtable, was held on the University of Nevada, Reno (UNR) campus on May 19, 2014. The workshop was hosted by UNR and the University of British Columbia. Knight Piésold?s local representatives, Bryan Ulrich and Logan Jensen, were joined by Tom Kerr, president of Knight Piésold?s, U.S. practice; Rick Frechette, senior vice president, environmental services and Jeff Coffin, geotechnical engineer, from the Denver, CO office for the roundtable event. The event played host to about two dozen attendees from several western states.

By A. A. El-Midany, R. M. Farag, A. M. Salem, S. E. El-Mofty

Bentonite is one of the main players in the stability of drilling mud. Its particle size and particle size distribution significantly affect drilling mud’s rheological properties. Although the Specifications for Drilling Fluids Materials report on Oil Companies Material Association (OCMA)-grade bentonite states that the API recommended powder having 2.5 percent mass fraction as the maximum value of residue of diameter greater than 75 μm, there is no other information on the specific size distribution for API bentonite. It was found that API bentonite has a specific size distribution with specific mixing weights. It is important to investigate why that mixture represents the optimum properties of drilling mud and how each individual size fraction has a specific function in the mixture. To clarify the effect of individual size as well as the collective effect of the size distribution, API bentonite was classified into different size fractions, with each tested separately for controlling properties such as filtration loss, plastic viscosity, gel strength, cake thickness and packing density.

By DEBASHISH MISHRA, SOMU MANDAL, ASFAR MOBIN KHAN, JAI KRISHNA PANDEY, NIROJ KUMAR MOHALIK, SANTOSH KUMAR RAY

Coal is a low-cost fuel with high calorific value. Statistically, the global coal mining industry suffered 12,489 fatalities in 104 reported mining accidents from coal dust explosions during 1900 to 2020. This review article discusses the occurrence, mechanism and explosibility parameters of coal dust explosions and presents a literature survey of the laboratory and computational fluid dynamics (CFD) simulation methods of studying them, as well as a comparison of the two methods.

Feb 1, 2023

By W. C. Wheeler, G. Suranyi, J. F. Gentleman, J. Muller, R. Kusiak

INTRODUCTION In 1974 two of the present authors reported the results of a pilot study indicating an increase of lung cancer risk in Ontario uranium miners. (Muller, Wheeler, 1973, 1974) The study was based on data contained in a computerized Mining Master File maintained by the Ontario Workmen's Compensation Board that contained information on miners examined in Ontario who had either 60 months of dust exposure in mines or had signs of pneumoconiosis or tuberculosis. Including the above conditions the definition of uranium miners added the condition of one month or more of uranium mining experience in Ontario. This list of Ontario uranium miners contained 8,649 names. Following the results of this first pilot study, we embarked on creating a file of uranium miners containing information on men with one month or more of uranium mining experience in Ontario without any further conditions. This file was used by the Royal Commission on the Health and Safety of Workers in Mines in their study of risk in Ontario uranium miners. (Hewitt 1976) This file contained 15,094 names. In this report we give an outline and progress report on a study of Ontario miners that we are conducting at present. It was felt that the male population of Ontario is not necessarily an adequate control population for uranium miners. A preliminary examination of the work history of uranium miners indicated that the majority of them (about 90 percent) had other mining experience in addition to their exposure in uranium mines. We therefore considered it useful to evaluate the possible effects of non-uranium mining on risk, and for this reason decided to make the Uranium Miners Study part of a study dealing with the mortality of Ontario miners in general. Aims of the Study The aims of the Study include the evaluation of: 1) the risk of dying by cause in non-uranium miners as compared to the male population of Ontario and Northern Ontario. 2) any differences that might exist in the death experience of non-uranium miners by cause according to ore mined. 3) the effect of length of exposure in non-uranium mines on age-specific risk by cause. 4) the dose-response function for primary cancer of the trachea, bronchus and lung from exposure to radon and its short-lived daughters. 5) the possible effect of the mining environment on deaths from causes other than cancer of the trachea, bronchus and lung. The study will address itself to a number of other factors that might well affect the dose-response function. These include: a) factors in the mine environment - other than radon daughters - that might affect lung cancer mortality. b) the effect of non-uranium mining on lung cancer risk in uranium miners. c) the effect of age as well as age at time of exposure on lung cancer risk. d) questions of latency and the possible dependence of latency on age at time of exposure. e) smoking as an important factor in lung cancer risk. f) Histological type of cancer in relation to the various parameters of exposure and age. MATERIALS AND METHODS The Study is making use of existing computerized data files and has set up certain new files. These include the Mining Master File and the Model Development File. The Mining Master File This file is a computerized record of data on individual miners obtained at yearly miners' examinations that have been carried out since the mid 1920's. The conditions for inclusion in the Mining Master File have been indicated above. Information contained in the file includes: (1) Identifying information: a) Surname and given names b) Date and place of birth c) Miners Certificate Number d) Social Insurance Number if available. (2) Updated Employment data obtained at each miner's examination: a) Year of first dust exposure in Ontario b) Year of first dust exposure outside Ontario c) Number of months worked in mining d) Ores mined e) Mining areas and mines f) Occupations

Jan 1, 1981