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By J. F. Burr, D. Snyder, W. Calder

This paper provides a determination of the equivalent level of protection of the international standards relative to similar criteria used by the U.S. Mine Safety and Health Administration (MSHA) to approve two-fault intrinsically safe (IS) stand-alone equipment. U.S. mining law requires such a determination for MSHA to use alternatives to existing standards. The primary issue is to demonstrate that the international standards for equipment evaluation will provide at least the same level of protection for miners as the document currently used by MSHA.

Jan 1, 2018

By J. F. Burr, D. Snyder, W. Calder

This paper provides a determination of the equivalent level of protection of the international standards relative to similar criteria used by the U.S. Mine Safety and Health Administration (MSHA) to approve two-fault intrinsically safe (IS) stand-alone equipment. U.S. mining law requires such a determination for MSHA to use alternatives to existing standards. The primary issue is to demonstrate that the international standards for equipment evaluation will provide at least the same level of protection for miners as the document currently used by MSHA.

Jan 1, 2017

By David C. Sanders, Rodney H. Sergent, Victor C. Storhok, Batric Pesic

In the past, considerable work has been done on the applica­bility of bromine chemistry in the extractive metallurgy of gold. While the research in this area spanned from the understanding of fundamental dissolution chemistry to the demonstration on a pilot plant scale, no work was done on the fate of discarded leach residues with respect to the stability of accompanied heavy met­als. Because the leach residues were the discharge products of halide/halogen systems, the general perception was that the con­tained heavy metals would be more susceptible to dissolution than in typical sulfate systems, thus causing increased environ­mental problems. A long-term study was performed to obtain the information on the stability of heavy metals contained in the leaching residues after bromination. The study involved the leach residues of three different ores, as well the precipitates prepared from the synthetic solutions (not presented here). The conclusion of this study is that the stability of solid residues produced by bromination leaching was same as the sta­bility of leach residues produced by leaching in the sulfate sys­tems. Also, contrary to the past expectations, the presence of bromide ions in the test solutions (up to 1 g/L NaBr) did not enhance the solubility of heavy metals (Cu, Zn, Pb, As) beyond the solubilities found in the sulfate systems.

Jan 1, 1998

By M. Nichols

Where am I? Where are they? Where is it? These are the fundamental questions that need to be answered in managing people and resources. This paper explains how GPS positioning technologies answer those fundamental questions and provide better information management from initial exploration work through daily mine operations to reclamation work and environmental monitoring.

Jan 1, 1998

By T. Matthews

"One critical factor in mineral reserves reporting, as well as mine-reserves reconciliation, is the impact of dilution and ore loss in the mining process. This paper considers the implications of various factors on dilution and ore loss projections, by orebody geometry, mining method, and ore control systems. We also discuss the implications of resource estimation methodology on dilution for reserves. DEFINITIONS Dilution and ore loss are two critical concepts in mining, which address the differences encountered between modeled grade and tonnages and actual production. Dilution is volume increase and grade reduction caused by multiple factors, chief among which are mining of waste material along ore-waste contacts, mining of internal waste as ore, and misclassification of waste as ore in the ore control process. There are also geostatistical and estimation aspects sometimes lumped with dilution, including the volume-variance effect (the tendency for small volumes of material to include a less regular distribution of grade than large volumes of material). Ore loss is described as reductions of ore volumes in the mining process due to misclassification of ore as waste in the ore control process, exclusion of discontinuous mineralization from mining due to geometry or continuity, and mechanical losses in the mining process. Dilution is typically taken as an increase in tonnes of ore with no change in contained metal (and thus results in a reduction in grade.) (Some workers consider the likely grade of the diluting material as well, particularly in deposits with gradational grade boundaries—this will be addressed later in the text.) Ore loss is typically taken as a reduction in tonnes at average grade of the ore, and thus results in a reduction in both tonnes and contained metal. If model (resource) tonnes are Mt, grade is Mg, and contained metal is Mm, the resource with ore loss (L) and dilution (D) included (Rt, Rg, and Rm) will be:"

Jan 1, 2015

By R. D. Lord

This paper deals with the search for the best practical means of storing sulphide bearing tailings, where there is no residual excess of carbonate material. It is the common experience that the sulphide content decomposes, with the aid of bacterial action, and the resulting sulphuric acid escapes, along with any heavy metal solutes, through embankments that are usually porous to some degree. The problem is typified in the tailings of the uranium operations of Elliot Lake, Ontario, where mining started some 20 years ago. The approach to tailings disposal paralleled the practice for other hydrometallurgical plants treating gold and base metal ores. Impoundment areas were designed to retain solids, and a clear and neutral overflow was considered satisfactory practice. Now experience has shown that these areas, some idle for over a dozen years, release acids, in seepage and overflows, to an unacceptable degree. To protect natural water courses neutralizing plants are operated wherever required. Lime slurry is fed continuously into the tailings outflows in a quantity sufficient to raise the pH to 8.5 and precipitate heavy metals that may be in solution. The objection to this procedure is that the plants will require servicing indefinitely, unless a better remedy is found.

Jan 1, 1975

By U. Thorley

This paper presents an overview of surface mining activity in the Canadian oil sands and how the mine operators interact with the province of Alberta's Mine Financial Security Program (MFSP), which took effect April 1, 2011. The MFSP approach to reclamation assurance results in the government of Alberta sharing a portion of reclamation liability through the majority of an oil sand mine's life. In order to determine the potential fiscal magnitude of this shared liability, an examination of the expected costs of oil sands reclamation activities through a study of corporate asset retirement obligation (ARO) liabilities and other corporate disclosures is presented. The province of Alberta's Environmental Protection Security Fund (EPSF), which formerly secured oil sands mine reclamation activities is discussed. Reclamation costs in the oil sands are poorly understood. The MFSP provides what it characterizes as a conservative estimate of C$75,000/ha, while corporate disclosures by Canadian Oil Sands Ltd. place expected costs at C$180,000/ha. There is significant risk associated with the apparent uncertainty surrounding reclamation costs.

Jan 1, 2012

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 D. M. Richards, A. D. MacPhail

Highland Valley Copper currently mines two low-grade ore bodies, Lornex and Valley. The partnership was formed in 1986. As a cost reduction measure, it was decided to use an in-pit crushing and conveying system to deliver the ore from the Valley Pit to the Lornex mill 3 km (1.8 miles) away and 175 m (575 ft) above the pit rim. The system uses two gyratory crushers that feed a series of conveyors to transport up to 130 kt/d (143,000 stpd) to the main stockpiles. This paper describes the performance of the in-pit crushing system as it is currently configured, as well as its evolution to date and future planned moves.

Jan 1, 1995

By D. W. Horsfall

The different types of processes used in fine coal beneficiation in the Republic of South Africa are listed, together with data giving an indication of their separating efficiencies The two classes of coal, fines and ultra-fines, present in the -0,s m fraction of the run of mine coal are discussed, with special reference to their beneficiation characteristics. Using those properties, together with the data on plant efficiency, case studies are worked out to indicate the advantages and disadvantages of the different processing routes available. The paper closes with an indication of areas where research is required to enable some of the processes to be applied to a greater extent than is presently the case.

Jan 1, 1988

By B. Hearn, O&apos

Falconbridge, Ltd. operates six mines (the strathcona, Fraser, Lockerby, Onaping, East and Kidd Creek) in the Sudbury and Timmins districts of northern Ontario (Fig. 1). These mines vary in depth to approximately 1500m and experience a wide variety of ground conditions. Problems of greatest concern include rockbursting, backfill pillar stability, wall and pillar stability, and the use of cable anchors. A study was initiated approximately two years ago to identify how numerical models could aid in the examination and possible understanding or solution of these problems. This paper discusses the use of numerical models at Falconbridge and describes a case history of their use in examination of rockbursting at the Strathcona Mine.

Jan 1, 1988

By Charles A. McLean

Bucketline dredges are machines for excavating large relatively unconsolidated or weakly consolidated materials from below water level. They are at the upper end of the capital cost range and the lower end of the operating cost range for placer mining machines and have digging capacities, typically, of from 100 cubic yards of bank measure material per operating hour for a shallow digging dredge carrying 2 cubic foot buckets to 1500 cubic yards per hour for a large deep digging dredge with 33 cubic foot buckets. Bucketline dredges used in the mining industry have their mineral processing plants mounted aboard the digging hull. Since dredges are high capital cost items, they require large ore reserves, typically at least ten years. Because of their high capital cost they are usually operated around the clock and for as many months of the year as weather conditions will permit. Typically a well run dredge operating year round would be expected to operate for 600 hours per month. Dredges operated in cold climates cannot operate when the weather freezes the dredge pond or the gravels, and dredges operating at sea cannot operate when high waves might batter the digging ladder against the bottom or upset the mineral extraction process.

Jan 1, 1992

By Robinson Leon-Diaz, Alberto Jaen-Toribio, Raymond Blanchard, Mike Deevy, Miguel Fuentes-Llanos

"Tunnels designed to NFPA 502 are required to withstand the RWS time-temperature curve, more specifically prevent progressive spalling and loss of strength of steel reinforcement. Fire boards or spray-on layers can be effective, however, these solutions have capital and whole-life cost implications. The use of “fire resistant” concrete based on a suitable aggregate with polypropylene fibers has also increased in recent years. This article presents a new methodology for thermal and structural analysis of segmentally lined tunnels, which permits the analysis of project specific fire curves and an assessment of different fire protection strategies. The effectiveness of fire boards is assessed along with whether “fire resistant” concrete alone is a viable means of achieving the required protection. Finally, since NFPA 502 recommends water-based fixed fire-fighting systems for Category C and D tunnels, we discuss the question of how a fixed fire-fighting system should be addressed within the structural design. INTRODUCTION Protecting road tunnels from structural damage and collapse is a key requirement for both life safety and business continuity. Where road tunnels are part of key highway corridors, protecting business continuity is a high priority for owners, operators and the Authority Having Jurisdiction. For existing tunnels, compliance with NFPA 502 may require upgrades with either passive fire protection and/or water-based fixed firefighting systems. For new tunnels, compliance with NFPA 502 requires a combination of good practice in design and fire testing. A water-based fixed firefighting system is a Conditionally Mandatory Requirement1 for Class C and D tunnels, i.e. all tunnels greater than 300m and 1000m long respectively. The basis for fire safety design of new tunnels and assessment of existing tunnels is the worst-case fire scenario. A number of factors, including but not limited to the following, influence this design fire scenario:"

Jan 1, 2016

By Todd Burchett

Mining engineers spend countless hours and resources when designing a new underground coal mine. Their primary objective is to design the safest and most efficient operating mine with regards to coal production. A key variable often overlooked in this design stage is the slope conveyor. Typically, a slope conveyor is expected to operate with a 98-percent or higher availability. However, too often little effort is put forth by the mining engineer to optimize its design. Coal companies will rely on engineering, procurement, construction and management (EPCM) companies for the preliminary design, because the slope conveyor will be considered part of the surface material handling processes. This preliminary design will be used when soliciting quotations for the slope conveyor. Unfortunately, EPCMs may not have enough expertise with conveyors to optimize the design. This expertise is available with an original equipment manufacture (OEM) of conveyors, which ultimately may be responsible for supplying the slope conveyor. Each OEM will provide a bid package that represents what it considers to be the optimal design.

Jan 1, 2013

By Kent Phillips, Meredith Scaggs-Witte, Emily Sarver, Cigden Keles

"After nearly four decades of decline, the prevalence of coal workers’ pneumoconiosis (CWP, or black lung) in the United States has been on the rise since the mid-1990s (Laney et al., 2014; Laney et al., 2010; Suarthana et al., 2011; Pollock et al., 2010; Antao et al., 2005; Blackley et al., 2016). Particularly alarming is the number of cases of rapidly progressive disease such as progressive massive fibrosis (PMF) (Pollock et al., 2010; Antao et al., 2005; Blackley et al., 2016; Laney et al., 2017). A recent study by Laney et al. (2017) observed 192 U.S. coal miners participating in the Coal Workers’ Health Surveillance Program (CWHSP) who had been diagnosed with PMF since 2000. Of the 163 (85 percent) that had a normal radiograph on file to use as a baseline, 27 (17 percent) of these individuals had progressed from a normal radiograph to PMF diagnosis in less than 10 years. Moreover, 162 (84 percent) of the individuals in that study worked in Kentucky, West Virginia or Virginia, and 169 (88 percent) had only ever mined underground. Blackley et al. (2016) also reported on a group of 60 PMF cases that were discovered by a single black lung clinic in eastern Kentucky. Since seeking care at such clinics and participation in the CWHSP are voluntary, and could be influenced by a number of factors, there has been some concern that these reports may overestimate the degree of resurgence in severe disease (i.e., versus disease that was previously under-reported). Even so, they highlight a critical need to better understand the cause(s) of disease development and progression — such that effective interventions can be devised.The notable uptick in CWP and PMF rates among miners in central Appalachia has led to this region being called a hot spot for disease (Pollock et al., 2010; Antao et al., 2005; Blackley et al., 2014; Laney et al., 2017). While the geographic clustering has been well documented (Pollock et al., 2010; Antao et al., 2005; Wade et al., 2011; Wang et al., 2013), the root cause is still unknown. Leading hypotheses have focused on the relative amount of rock being cut along with coal in many central Appalachian mines, as there has been a tendency to mine increasingly thinner coal seams over the past couple of decades (Laney et al., 2010; Schatzel, 2009). This shift has likely been accompanied by changes in specific dust exposure factors, such as increased abundance of particularly harmful dust constituents (e.g., silica or silicates) or increased frequency of harmful exposures (e.g., due to work in more risky environments) (Pollock et al., 2010; Blackley et al., 2016; Cohen et al., 2016; Douglas et al., 1986)."

Jan 5, 2018

By Peter J. Huck, Bruce G. Stegman, Richard E. Thill

Introduction Backfilling of mine voids is used to prevent or control the effects of subsidence on surface structures. The pumped-slurry, blind backfilling process has been successful for stabilizing ground over abandoned and inaccessible underground coal mines. This article describes the systematic evaluation of potential monitoring systems that would improve backfill monitoring technology. It also details field proof-of-concept tests that were conducted on two systems and the difficulties encountered in implementing them. Ground subsidence over abandoned mines can have devastating effects on overlying urban areas decades after the closing of room-and-pillar mines. The result may be cracked foundations, ruptured gas and water lines, broken sewers, distortion or cracking in superstructures, and sinks and potholes in the ground surface. About 32,000 km2 (8 million acres) of land in the US has been undermined for coal. According to the US General Accounting Office, 8,100 km2 (2 million acres) have undergone subsidence and another 8,100 km2 (2 million acres) are expected to subside by the year 2000. Actual figures on land affected or threatened by subsidence are probably much higher, since these estimates were based on late 1960s studies. For more than two decades, the US Bureau of Mines has been engaged in stabilizing ground in urban areas having high risk potential for subsidence costing millions of dollars. Thousands of acres have been stabilized, protecting property worth hundreds of millions of dollars. In earlier years, backfilling was by in-mine stowing in accessible mines or by gravity-feed sluicing methods in inaccessible mines. Pumped-slurry methods have been used extensively in the past 10 years. More slurry can be injected for fill from fewer injection holes over extensive areas in abandoned mines. Since this method requires fewer boreholes, there is less disruption of surface facilities. An investigation was conducted to determine the feasibility of using advanced, remote sensing or monitoring technology for application in monitoring fill placement. Specifically, the objective was to develop conceptual systems for blind backfill monitoring that require fewer boreholes and give better definition than is now possible. Blind Backfilling Methods Blind backfilling operations are conducted from the surface and do not require personnel and equipment underground. These methods are applicable to abandoned, inaccessible workings. Two categories of blind back-filling are point support, practiced by civil engineers to protect individual structures or surface facilities, and areal backfilling methods, used to protect large areas against subsidence. Point Support Methods Point support methods are usually gravity-feed systems. In general, point support methods use small volumes of expensive fill material and require a large number of boreholes within a constructed site. Because of the processed material used for back-filling and the close spacing of the injection boreholes, control and monitoring often may be accomplished by borehole cameras. Areal Backfilling Areal backfilling is conducted mainly by the pumped-slurry injection process (Fig. 1). In eastern and interior coalfields, material used is often mine refuse or flyash, both being undesirable on the surface and costly to dispose of in an environmentally acceptable manner. Hence, the use of

Jan 12, 1983

By J de Cuyper, N. R. Tipman, G. E. Agar, L. Laré, W. Freyberger

The flotation chemistry of the commercial INCO matte separation process was investigated. The slow cooling of Bessemer converter matte forms discrete phases of Cu2S and Ni3S2 and a Cu-Ni alloy. After magnetically removing the alloy, the Cu2S and Ni3S2 are separated by flotation at pH 12.4 (saturated lime) using diphenyl guanidine (DPG) as both collector and frother. DPG has been used exclusively in this flotation process because of its unusual selectivity for copper minerals. The surface product resulting from chemisorption of DPG onto the Cu2S was identified as the double salt Cu(DPG)2SO4,.CU(DPG)2(OH)2. The adsorption followed Langmuir behaviour up to a monolayer coverage. In the absence of DPG, the rapid adsorption of oxygen by Cu2S in flotation pulps was observed. The surface product was identified as the insoluble basic copper sulfate CuSO4.3Cu(OH)2 with the production of sulfate ion. In the presence of DPG, the oxidation reaction appears to be suppressed. The frothing properties of DPG and commercial frothers were compared. DPG is not a powerful frother. Batch flotation tests confirmed that DPG is a highly selective collector when compared to most sulfhydryl collectors.

Jan 1, 1976

By C. C. Harvey

Asia is experiencing a growth market for industrial kaolins for use in ceramics, paper, plastics and other market sectors. Export and import data for the Asian countries reflects this growth with the Peoples Republic of China as the major exporter of clays and Japan the major importer. The growth in tonnage and product sophistication of kaolins produced on Belitung in Indonesia is typical of developments that are taking place in many locations in Asia. This region therefore presents opportunities for mineral processors and a challenge for the exploration geologist, the mineral processing engineer, the mineral economist and the marketing specialist.

Jan 1, 1996

By Kanchan Mondal, Gopi Bylapudi, Anand Bhagwat, A. J. S. (Sam) Spearing

Corrosion of steel roof support systems can cause potential premature failure of the support, thus adversely affecting the excavation stability and rock-related safety. An in-house corrosion test system was designed and developed to test full-length roof bolts for material performance based on tensile load capacity and strength under different corrosive conditions found underground. Initially, ASTM A615 grade 60 steel roof bolts, which are the most commonly used bolt material in the United States, were tested with and without stresses in a simulated underground coal-mining environment for approximately six months. This paper mainly discusses the test system, protocol and system shortcomings, and makes recommendations based on the observations and results.

By R. Elias

Botswana is a mining-dominated sub-Saharan country. Workforces are characterised by poorly educated operators and front line supervisors, with equipment and management to 1st World standards. Poor communication, ignorance of business objectives, inability to meet targets, and lack of problem-solving capacity are the norm. Training leads to high expectations and is of concern to management as a source of dissatisfaction, despite the long-term benefits higher skills have for mine viability. The aims of a technical training programme are presented with various models and approaches being implemented at operations in Botswana. These are used to construct a series of guidelines for technical training initiatives.

Jan 1, 2000