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By Peter Fischer

Reducing mining costs has become such an important factor in the German coal industry that operators are forced to work only those areas where production costs can be kept low. These areas will normally be located close to the mine shafts because they are easily accessible. Even the shaft pillar is now being considered as part of the winning zone. Before working coal in shaft pillar zones it is essential to assess the impact this will have on the shaft lining. There is a huge difference between sliding and strata-anchored shaft systems. However, if the overburden comprises lightweight soil both types of shaft will have a tendency to protrude from the surrounding ground. This paper presents the geomechanical reasons underlying this reaction and the methods used for predicting and measuring it.

Jan 1, 2007

By Dean Workman

Located in downtown New York City, this project necessitated an innovative conveyor design for successful muck removal. This paper will discuss the technical challenges and engineering solutions of the muck transport system which consists of every commonly recognized version of a belt conveyor. The elaborate system includes a TBM conveyor integral to the back-up system, a wall-mounted extensible conveyor, a crown-mounted transfer conveyor, a floor-mounted fixed-length conveyor, a pocket-belt vertical conveyor, three cascading overland conveyors, and one radial stacker. The most challenging design element was an over-land conveyor featuring a box truss for muck transportation over Northern Boulevard while simultaneously going under the Queens Plaza railroad viaduct. An overview of the project is provided along with the following topics: developing final plans from the proposal concept, interfacing with existing works, communication with the joint venture, and complying with local regulations.

Jan 1, 2008

By J. Finch, R. McIvor

This paper presents the development of a new grinding circuit steady-state modeling system. It is fundamentally based on the “functional performance equation”, which has now been used to improve the performance of numerous grinding circuits. This equation characterizes the two distinct efficiencies that are at work in a ball milling circuit, and how these relate to overall circuit productivity. It does so based on the particle size chosen to distinguish between coarse and fine (product size) material. Now, by applying it to all the material size classes, a simple yet reliable ball mill model was created. Combined with cyclone recoveries, the complete, detailed grinding circuit performance can be exactly reproduced mathematically by the computer program. It can then be used with separate process equipment application engineering methods to systematically engineer grinding circuit improvements. The development, features, uses and limitations of the system are described.

Jan 1, 2007

By G R. Howard, G Back

Management of information systems for data collection is essential to maintain data integrity and continuity, and manage loss control on a large world-class mine such as Telfer Gold Mine. This paper aims to describe the individual systems and protocols of geological data capture at Telfer, then focus on Quality Assurance Quality Control data as an example of loss control in practice. Loss control systems are required to provide capacity, flexibility, structure and management tools to enhance data interrogation. The data that have been collected can then provide geological, financial, environmental, and contractual information to optimise management of business best practice. Telfer Gold Mine is a wholly owned and operated subsidiary of Newcrest Mining Limited. The mine is located in a remote area of NW Western Australia, and has been operating for 20 years. Geological data have been collected at Telfer since 1973. The data include drilling, assay, geological, survey, structural and geophysical data. Data management has evolved through many systems with data stored on many different hardware and software platforms. Commencing in 1995, collation, standardisation and validation of the historic data was completed. This has resulted in the first Access based drill hole database incorporating all available drilling data. This drill hole database, now hosted in SQL Server, is the hub for all geology related data management systems. The Telfer Gold Mine Geology Department has developed a series of inter-related database systems in order to manage the core geology business issues. Databases relating to drill hole planning, drill contract management, geological logging, accounting (standard costing, forecasting, invoice reconciliation), quality control (QAQC), and environment rehabilitation have all been developed to manage loss control. Management effort to provide adequate data systems and protocols has driven the system from concept to utilisation. The improved productivity, data integrity and data analysis capabilities provided by the new database systems at Telfer have allowed for greater confidence in decision making. Systems such as the drill hole and QAQC databases, when utilised in the proper manner provide up-to-date data analysis for resource audits and contract negotiations. The loss control systems are essential to maintain confidence in data integrity and hence directly effect the future of mining at Telfer.

Jan 1, 2000

"Lax, misguided, and dangerous" is Rep. James Santini's description of the official US position on strategic nonfuel minerals. Santini (D-NV), chairman of the House Mines and Mining Subcommittee, criticized the Interior Department for "its long record of benign neglect" regarding the domestic minerals crisis. Santini made his remarks at a news conference at the American Mining Congress convention in San Francisco, where he released his subcommittee report "US Minerals Vulnerability: National Policy Implications." The report-said to be the first major congressional study of the minerals issue by a committee of jurisdiction is the result of a two-year inquiry. The investigation was undertaken, according to the chairman, "because no person or agency in the executive branch of government fully grasps the critical importance of nonfuel minerals to the nation's economy, defense, and quality of life." The report also urges a larger role for the Department of Defense, which has "stood passively by for many years as a consuming by-stander," according to the report. President Carter's incomplete Non-fuel Minerals Policy Review also drew the committee's ire; Santini calls it "a tragic waste that cost tax-payers $3.5 million and the loss of some 13,000 person-days." The subcommittee examined the following issues for its report: • The US minerals industry's inability to meet national raw material needs under a "hodgepodge of contradictory, restrictive, and irrational" federal regulations; • Dependency on foreign sources of strategic minerals in times of "increasing resource nationalism" and "Soviet mineral expansionism;" • National security needs for foreign mineral resources that do not have effective substitutes; • The US government's approach to national minerals policy "amid a growing realization that such a policy does not exist." The subcommittee report includes an analysis of public and private studies on nonfuel minerals and discusses a series of policy problem areas that negatively affect domestic production. Capital formation disincentives, tax policies, antitrust enforcement, environmental laws, health and safety regulations, technical problems, and restricted access to federally-controlled public lands contribute to what Santini calls a "tragic irony." "The irony is that we are a nation vastly rich in mineral resources yet our own government chooses to stifle development of these critical raw materials and thereby increase offshore reliance. The tragedy is that we also are ensuring US vulnerability to severe economic dislocations and a weakening of our national security." In just six years, from 1973-1978, the US trade deficit in nonfuel minerals rose from $2 billion per year to $8 billion, according to the report. The country imports more than 50% of 23 critical minerals, including 100% of its manganese, chromium, cobalt and platinum. The US is promoting its dependence on foreign mineral sources at the very time the security of many of those sources is becoming less certain, the report notes. Santini said the subcommittee investigation revealed a vulnerability that may be more serious and pervasive than that of foreign oil. The US may be able to develop alternate energy resources, but there are no effective substitutes for many nonfuel minerals. The report also discloses that US stockpiles of critical and strategic minerals are of inadequate supply and quality. Holdings of some vital minerals are far below present objectives, and for some there are no holdings at all, according to Santini. To resolve the current crisis, the report makes the following recommendations: • Complete immediately President Carter's Interagency Nonfuel Minerals Policy Review; • Implement (throught the Interior Department) the 1970 Mining and Minerals Policy Act; • Create an Office of Energy and Minerals with the same stature, power, and oversight responsibilities as the Council on Environmental Quality; • Ease federal restrictions on mineral exploration and development on public lands and implement a complete review of public land use policies; •Fund for and fulfill US nonfuel minerals stockpiling objectives; •Increase federal funding for non-

Jan 11, 1980

By Christopher Davey, Marian Mazurkiewicz, Yvonne Spooner, Dana Hankey, Peter Kanjorski

The concept of a high pressure liquid jet mill with highly unsteady flow, has been developed and recently patented by Cornerstone Technologies LLC (CsT), for the purpose of micron and sub-micron particle production. The mill accepts feed sizes up to 15mm for some materials and is capable of submicron production. Successful material range from precious metals such as silver and palladium to dielectric components and substrates such as Barium Titanate slips, zirconia, titania and silica. The process has also succeeded in adequately reducing the size of materials for both composite and coating uses such as anthracite coal, graphite, chrome metal, wollastonite and more than 100 others. A unique design approach has been taken to highly maximize the energy flux in the mill's chambers to create extremely high turbulence and destructive cavitation. This is assisted by shock waves, which cause particles to undergo ultra high frequency pressure pulsations, high frequency collisions and then abrasion, shattering, hydrowedging, and cleaving. Due to these extreme properties the processing occurs in just fractions of a second allowing throughputs up to 1000 kg/h on a machine that would fit inside a 60 cm box. The technical solution and technological advance, as well as the environmental and economic benefits indicate rapid and wide spread acceptance of high-pressure liquid jet milling in modern industry.

Jan 1, 2003

By J. B. Brodie, C. Pelletier

"The vulnerability of Canadian and U.S. companies, their directors, officers and employees to onerous penalties associated with violations of environmental statutes and common law actions has provided the impetus for the increasing use of environmental audits. This trend is developing in direct proponion to the cost and difficulty of obtaining liability insurance. Companies operating in British Columbia should be cognizant of developing legislative and enforcement trends and their implications for individual and corporate responsibility. Canadian mining companies doing business in the U.S. should be particularly aware of the environmental exposure which may be assumed with property acquisition or by operations which produce or use any of an ever-increasing list of regulated substances.The environmental audit is now a key component of prudent business planning which will identify noncompliances and environmental liabilities, outline defensive strategies, and assist in a legal defence should charges be laid. This paper will discuss the purpose and mechanics of an environmental audit with emphasis on those features which will maximize protection against statutory and common law actions.IntroductionThe environmental audit is but one weapon in a comprehensive defensive strategy for corporate and individual survival in an increasingly litigious world. The principles of the environmental audit have been formulated as a logical response by management to an ever-growing list of environmental vulnerabilities, which often have the potential to result in plant shutdowns, prosecutions or fmancial liability of major proportions. Accordingly, the audit may play a critical role in maintaining profitability as well as assisting in the defence of a company and its employees against actions taken by regulatory agencies and citi7.cns under statute and common law. Should convictions result from these actions, the penalties are likely to be ameliorated by the demonstration of due diligence through management policy supporting the audit procedure.An awareness of environmental sensitivities, strict adherence to licensing requirements, and planning for environmental emergencies are now generally considered to be as important to profitable performance as operating costs, metal prices, and labour peace. Why is this so? The increased priority given to environmental matters is partly a result of changing attitudes amongst the mining profession, but perhaps more importantly, it is also a direct consequence of the proliferation of ever more stringent environmental legislation, the targeting of management for responsibility and the draconian penalties imposed for violations of such legislation. Contributing to this trend are recent court decisions involving disputes of an environmental nature in which the standard of care required for a successful defence now requires almost super-human diligence in environmental management. The principle of ""strict liability"" (in which negligence or permit violation does not have to be shown) is also being increasingly applied in the resolution of civil actions."

Jan 1, 1988

By K. Park

Coupled influence of sulphidizers and xanthates on the electrokinetic property and flotation behavior of malachite was systematically examined via electrophoretic mobility measurements and microflotation tests. The electrophoretic mobility results for the malachite before and after surface modification with different types (Na2S and (NH4)2S) and amounts (1×10-7?1×10-4 moles/g) of sulphidizers, showed that the isoelectric points (IEP) of malachite differed at the low dosage level depending on the type of the sulphidizer, which ranged between 5 and 9.5. However, the IEP values were observed to be shifted from high to low pH values with increasing amount of sulphidizers and finally ranged between 3 and 4, indicating that the sulphidizers played a different role on changing the surface property of malachite. In order to further understand the effect of sulphidizers on the electrokinetic property and flotation behavior of malachite in a sulphidizer+xanthate system, flotation tests were carried out with malachite sulphidized with Na2S and (NH4)2S (adsorptive amount=8×10-5 moles/g) at different bulk xanthate concentrations. The results showed that the flotability of (NH4)2S-treated malachite was greater than Na2S-treated one over the entire xanthate concentration investigated, indicating that the type of sulphidizers played important role in malachite flotation; however, no obvious correlation between electrokinetic property and flotability of malachite was observed.

Feb 27, 2013

By ATF Publications

The following is a summary of the changes that were incorporated into the new Federal Explosives Regulations, 27 CFR Part 55, dated 9/2000. However, in light of the recent events of September 2001, additional changes in the Federal Explosives Laws and Regulations may be forthcoming. The nature and extent of any such potential changes are impossible to gauge at this time. However, this synopsis of the changes contained in the September 2000 Orange Book, ATF P 5400.7 was current at the time of this writing. Any questions regarding this paper should be directed to the Public Safety Branch in ATF Headquarters in Washington, D.C.

Jan 1, 2002

By Narendra Gupta, Gaurav Srivastava, Abhinav Sharma

From the days when plain detonators and safety fuse were used for initiation of commercial explosives, the commercial blasting and mining industries have made rapid strides. With the advent of electronic detonators in the late ‘90s, the face of commercial blasting was changed forever. The Mining Industry in India initially took a while to embrace Electronic Blasting Systems (EBS), however, more recently the industry has taken to EBS in a big way.

Jan 1, 2015

By Ike Isagon

Backfilling has become an integral process in underground mining operations, with varying cost-effective forms of application. This study is a part of an overall investigation into the backfill practices at Copper Cliff North Mine (CCNM). The mine is well-diversified in terms of backfill methodologies and practices. The mine employs different fill methods such as cemented and un-cemented rock fill, slag fill, and cemented hydraulic fill (or a combination of them) in order to fill the voids created by mining activities. The history of backfilling at CCNM has been dominated by cemented and un-cemented slag fill. Each fill method requires operating and engineering guidelines for a cost effective quality control system. The purpose of this paper is to briefly discuss the backfill methods and applications, operating guidelines, and engineering requirements at CCNM.

May 1, 2011

By E. R. Bauer

Previous studies and research efforts have shown that noise-induced hearing loss (NIHL) is a problem in the U.S. mining industry. This is especially true in surface and underground coal and stone mining where large, noisy equipment predominate. Workers in coal preparation and stone processing plants have also been found to be subject to high sound levels that could potentially cause NIHL over prolonged periods of exposure. National Institute for Occupational Safety and Health (NIOSH) researchers have been conducting a cross-sectional survey of equipment noise and worker noise exposures in the mining industry to estimate the potential for NIHL within the mining community. One commodity recently surveyed was the extraction of sand and gravel from surface pits and by river dredging. Little is known about the noise environment and worker exposures in these environments, where processing and mining equipment similar to coal and stone are employed. To address the potential for NIHL in the sand and gravel industry, sound levels on and around the dredges and processing equipment were recorded to identify areas of high noise levels. Full-shift worker dosimetry, in conjunction with task observations, was documented to determine the relationship between exposure and source. This paper presents research examining noise on dredges, in several surface mine sand and gravel operations and in the processing facilities. The locations where workers are likely to be overexposed and were found to be most susceptible to noise overexposures are reported. Results indicate that there are areas on the dredges (crane, suction pumps, and diesel engines) where sound levels greater than 90 dB(A) are present. In addition, crushers and screens used in the processing of the sand and gravel also generate sound levels greater than 90 dB(A). Although no surveyed worker exceeded the Mine Safety and Health Administration (MSHA) Permissible Exposure Level (PEL) of 90 dB(A) TWA8, laborers, mechanics, oilers, helpers, pickers, and greasers are the workers likely to be exposed to hazardous sound levels and thus develop NIHL over time. Knowledge of the equipment noise, area sound levels, and worker dose levels is information that management and employees can use to reduce exposures. Exposures can be reduced in certain areas through administrative controls and through engineering controls applied to the noisiest equipment.

Jan 1, 2008

By D. Moradkhani

Copper metal has important role in the basic industrials, as if it did not exist, modern human life would not develop! Copper leaching, as the first step, is important step in copper production processes. In this research, efficient factors on the leaching have been investigated. For this reason, four efficient factors on leaching namely pH, liquid to solid ratio (L/S), temperature and time, as independent variables, were optimized using response surface (RSM) with D-optimal. A quadratic equation was used to create response and contours. According to the results from analysis of variance (ANOVA), the value of determination coefficient (R2=96.77%) indicates that the model was good fit. Optimum experiment condition also was found: pH of 1, L/S of 8.24, temperature of 26.06 ? and time of 43.64 min. At this condition, the maximum recovery of copper was equaled to 92/38 in which good desirability achieved.

Sep 1, 2012

By Fredrick L. Johnson

The Jerry Peak, Jerry Peak West, and Boulder Creep: Wilderness Study Areas contain no identified mineral resources. Two workings, a 20-ft-long adit and a pit, were found in Paleozoic, brecciated, limonitic jasperoid in the east part of the Jerry Peak Wilderness Study Area (WSA), but no significant metallic mineral values were noted. Lenses and pods of quartz containing copper minerals occur in Paleozoic sedimentary rocks 1/2 mi north of the Jerry Peak West WSA. Similar rocks crop out along Pine Creep: in that study area but no copper-bearing quartz lenses were found.

Jan 1, 1984

By A. D. Davis

The Gilt Edge Superfund Site is a former heap-leach gold mine that currently is being remediated in the Black Hills of South Dakota. Mine runoff water is treated before release from the site. The field pH, before treatment, is about 3, and the water contains arsenic and some heavy metals, in addition to sulfate concentrations of about 1400 to 1500 mg/L. In the Keystone area of the Black Hills, naturally occurring arsenic has been detected in ground-water samples from wells. Keystone City Well #4, which is not used currently, showed arsenic concentrations of 36 parts per billion (ppb) and sulfate concentrations of about 19 mg/L. With field samples of water from these sites, a limestone-based method was successful in reducing arsenic and heavy metals concentrations. The results are significant because previous research with the limestone-based method mainly had involved samples prepared with distilled water in the laboratory, in which interference of other ions such as sulfate did not occur. The research indicates the potential for broader field applications of the limestone-based removal method.

Jan 1, 2011

By R. Q. Honaker

Dense medium processes are used to clean over 50% of the coal that is fed into preparation plant facilities worldwide. The dense medium is formed using ultrafine magnetite which is recovered after the cleaning step using drain-and-rinse screens and magnetic separators. Despite the high efficiency of the recovery system, magnetite losses of around 0.5 to 1.0 kg/ton are common. Considering the recent escalation of magnetite to around $300/ton, an alternative source of magnetic material from coal combustion bottom ash has been investigated. A relatively low cost recovery system has been developed. Dense-medium tests using the bottom ash magnetics revealed a high level of efficiency as indicated by probable error values around 0.03 over the range of medium densities investigated. The results from both the recovery and coal cleaning efforts will be discussed in detail.

Jan 1, 2009

By Robert A. Elgin

The Leadville mining-district (fig. 1) covers approximately 8 square miles adjacent to Leadville, the county seat of Lake County, Colo. It is famous for its large production of rich ores containing zinc, lead, copper, gold, and silver. Some manganiferous ores also have been produced.

Jan 1, 1949

By Q. Zhang

The necessary capability of the gravity transportation pipeline system for cemented coal gangue backfilling at the Suncun Coal Mine, China, is about 74.4 m3?h-1 according to mining production and working times in the mine. It is estimated that the working velocity and maximum pipe length-backfill depth ratio of the backfill system are 3.82m?s-1 and 5.4, respectively and that the probable backfill capability of the system is 110.18m3?h-1. Results of hydraulic calculations for the backfill transportation system show that the designed backfill system is reliable in flowability and sufficient for backfill capability needs.

May 1, 2007

By Robert B. Hopler

The hazards which naturally prevail in underground coal mines, always severe and unpredictable due to the loosely-consolidated strata in which coal is frequently found, are increased by the commonly-occurring combination of coal dust, methane, and explosives. It was recognized by the mid-nineteenth century that coal dust was the basic factor contributing to disastrous explosions killing hundreds of miners, and that the ignition of methane gas was often the source of the coal dust explosions. It was apparent that preventing the ignition of methane was a critical part of avoiding these disasters, and it was also apparent that one cause of such ignitions was the firing of explosives. In addition, it was found that dust explosions were often initiated by blown-out shots of explosives in the absence of methane.

Jan 1, 1996

In the dimension stone industry, workers in processing shops may be exposed to harmful levels of respirable silica dust when conducting the different tasks in stone preparation, which include cutting, grinding, polishing, and thermaling. To protect workers from this health hazard, operators sometimes ventilate processing shops using fan-powered dust collectors to capture and filter dust. To investigate this issue, NIOSH, Pittsburgh Research Laboratory, in cooperation with a dimension stone operation, upgraded an off-the-shelf dust collector the operator was utilizing in a polishing/cutting shop. Initial dust surveys showed that the unit was under-designed for the amount of dust being generated in the shop. The objective of the research was to cost-effectively increase the air cleaning volume and improve dust capture efficiency of the unit with a larger motor and blower. The unit?s original stock 0.56 kw motor and blower was replaced with a 2.24 kw motor and matching blower to increase airflow. The unit was evaluated both in the laboratory and the shop before and after the retrofit to determine the improvement of the upgrade. The study showed that the 2.24 kw upgrade improved the performance over the original 0.56 kw motor resulting in more dust being cleaned from the ambient air in the shop. The 2.24 kw unit cleaned 19% more air and captured 32% more respirable dust than the 0.56 kw unit.

Jan 1, 2009