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By H W. Wu, T Harvey

An overview is given of two new developments in mine atmospheric monitoring. A new personal dust monitor (PDM) that gives real-time respirable dust readings is discussed. The unit is mounted within the minerÆs cap lamp battery and internally measures the true particle mass of dust collected on its filter. Samples are available for later mineralogical analysis and results do not exhibit the same sensitivity to water spray as optically-based measurement approaches. The technique achieves microgram-level mass resolution even in the hostile mine environment and reports dust loading data on a continuous basis. The monitor has been evaluated under an Australian Coal Association Research Program (ACARP) grant and is being adopted for statutory mine respirable dust determinations in the United States (US). The monitor has particular application for determining location of high dust sources. It can evaluate the efficiency of engineering means of suppression and other approaches to reducing dust levels. It has been recognised that the PDMÆs unique measurement approach has application to allow real-time atmospheric diesel particulate matter (DPM) monitoring. The industry has no real-time atmospheric DPM monitor at present. Recent surveys in New South Wales and Queensland show significant numbers of miners continue to face full shift DPM exposures in excess of internationally accepted levels. Real-time DPM monitoring will allow the industry to pinpoint high exposure zones where a number of trucks and other vehicles work in areas of poor ventilation. Knowledge of high DPM concentration zones allows efficient modification of work practices to reduce underground minersÆ exposure. Approaches to uses of the DPM form of the monitor and the design of tag boards are discussed. Some outcomes from mine tests with both these new instruments are given.

Jan 1, 2008

By R. Ward Stahl

This publication is a revision of Report of Investigations 5363 updated to reflect the improvement in fire protection at selected coal mines and contains suggestions on what may be considered good fire protective equipment, suggested methods of organizing the attack on fires at various locations underground, and helpful hints on testing and evaluating firefighting facilities.

Jan 1, 1968

This Bureau of Mines investigation addressed two primary issues of air velocity measurement in mines: the determination and use of correction factors, and the development of guidelines for the selection of a suitable site at which the measurements should be taken. Other facets of the investigation included a comparison of measurement methods and devices, and aircourse cross-sectional area measurement. The study consisted of theoretical, laboratory, and in-mine investigations. The measurement devices included in the experimental phase were vane anemometer, vortex shedding anemometer, a prototype thermoan-emometer, smoke tube, and oil of wintergreen sprayer. The measurement methods included single-point centerline, timed-point traverse, continuous traverse for the anemometers, and various distances and cloud positions for the smoke tube and oil of wintergreen devices. The study resulted in guidelines for measurement site selection that are applicable to most inmine situations. It also showed that the use of correction factors is problematic. There are many potential pit-falls and there are cogent arguments against using certain correction factors. However, generalized correction factors were developed that can be successfully applied in routine ventilation work, provided that their use is properly understood.

Jan 1, 1985

By Borje Bjorkvall

At LKAB's plants in Lappland, Sweden, sintered pellets are manu-factured according to three different industrial processes, viz. shaft furnace at Malmberget, straight-grate at Kiruna and grate-kiln at Svappavaara. At present the total annual capacity amounts to 4.7 million tons. However, since it has been decided to erect a new straight-grate plant (2.5 million tons) at Malmberget, and because of the decision to extend and rebuild the existing plants, it is estimated that the annual capacity will be increased to somewhat over 8 million tons by 1973. The great majority of the pellets produced is exported. They are thus reloaded several times and generally speaking roughly handled, resulting in larger or smaller product losses on arrival at the point of use. It is there-fore of great economical interest to have a good control over the transport strength of the pellets by appropriate quality testing at the point of production. In addition to good transport strength, further demands are ob-viously made on pellets destined for blast furnace operation. The blast furnace burden must maintain a good permeability for the gas. The pellets must thus have a favourable size distribution and must not be so weakened by reduction that they disintegrate under the stresses and clog the blast furnace shaft. Furthermore, the burden must have good reducibility. An increase of the rate of reduction can obviously mean increased blast furnace capacity and reduced coke consumption. In order to optimise the properties of the pellets in these respects, the producer must also be thoroughly familiar with their behaviour during reduction, particularly as the customer's interest in the reduction properties of the pellets' has increased over the last few years. Up to now the only quality demands the customer has made have generally had to do with the cold strength and the screen analysis. Thus a quality control of in addition to good transport strength, further demands are obviously made on pellets destined for blast furnace operation. The blast furnace burden must maintain a good permeability for the gas. The pellets must thus have a favourable size distribution and must not be so weakened by reduction that they disintegrate under the stresses and clog the blast furnace shaft. Furthermore, the burden must have good reducibility. An increase of the rate of reduction can obviously mean increased blast furnace capacity and reduced coke consumption. In order to optimise the properties of the pellets in these respects, the producer must also be thoroughly familiar with their behaviour during reduction, particularly as the customer's interest in the reduction properties of the pellets' has increased over the last few years. Up to now the only quality demands the customer has made have generally had to do with the cold strength and the screen analysis. Thus a quality control of

Jan 1, 1972

By J. E. Dreier, R. E. Scheffel, A. Guzman

"This paper outlines a comprehensive, cost-effective testing program for the acid-ferric sulfate heap leaching of oxide, supergene and primary copper ores. It is based on extensive experience in copper heap leaching and uses the many technological advances in the field developed over the past several decades. The approach described requires firstly a detailed resource evaluation, then a hydrodynamic characterization of representative samples and, finally, a focused metallurgical testing program. The principles communicated here can be applied to other acid leachable minerals. The program varies considerably from conventional testing in its disciplined, orderly, step-by-step approach, its application of hydrological and chemical principles to leaching, and its reliance on fewer, more tightly controlled column tests. The purpose of the test program is to optimize the financial, time and other resources devoted to the program, while minimizing the financial risks to the development company or companies and the project funding providers. IntroductionThe major goal of any process development testing program should be the successful implementation of the project. With respect to heap leaching, the metallurgical testing program plays a critical role in the larger objective, as described in Scheffel (2013, 2014). McNulty’s series of papers (1998, 2004, 2014) confirm that the success of any project is directly proportional to the extent and quality of the testing program on which the process is designed.Therefore, a key development objective is to conduct a well-focused metallurgical test program. While the primary focus of this paper is copper, the acid leaching of any substance would benefit from a similar approach.This paper addresses primarily the sulfate system, which is compatible with the bioleaching of sulfide minerals. Nicol et al. (2011) described the advantages of the chloride leaching of copper sulfide minerals. United States patents Nos. US 2009/0173188 A1, US 8,597,933 B2 and US2015/0232963 A1, assigned to BHP Chile Inc. and BHP Billiton S.A. Ltd, describe methods for both the oxidative and nonoxidative leaching of primary and secondary copper sulfides. Reyes (2013) and Ipinza and Flaquer (2014) described commercial applications of chloride-based heap leaching. The testing disciplines discussed in this paper will also apply to the development of an acidic chloride leaching system."

Jan 1, 2016

By S. H. Ash

No single factor in modern civilization has played a more important part in the lives of our people than mechanization in industry and to it civilization owes much of its progress. In no industry has mechanization met more opposition than in coal mining, where ?the introduction of mechanical equipment has been opposed on many fronts for economic and social reasons. The term 'mechanization? as used in this report refers to the application of machinery to cutting, loading, and transporting coal from the face to the mine cars. During 1933, 84.7 per cent of the underground production of the bitu-minous-coal mines of the United States (1) was cut by machines, while in Washington only 17.6 per cent was machine-cut. Information in this report has been obtained from personal observations and from operating officials in the Roslyn-Cle Elum coal fields, especially D. R. Swem, manager of coal operations, and Thomas Murphy, superintendent, of the Northwestern Improvement Company, to whom the author is indebted for assistance. INTRODUCTION Although Washington coal-mining problems relating co mining methods, ventilation, drainage, and preparation of coal have been discussed in many publications, little has been published on mechanization in this region, principally because it has not been accepted generally that mining machines, mechanical loaders, and conveyors are necessary or economically adaptable to the variable and steeply inclined coal beds of Washington. Production of coal in Washington reached its maximum in 1918, when 4,128,424 short tons were produced; from that year, the trend was downward until 1934, when production was 1,383,103 short tons, the lowest since 1898; for the past two years, production has risen steadily.

Jan 1, 1937

By Tuncel M. Yegulalp, Selamet G. Ergelebi

A description is given of a method of analysing modern mining systems in terms of reliability and their effects on productivity. Non-exponential distributions, such as the Weibull and lognormal distributions, for failure and equipment repair times are also considered. The resulting non-homogeneous Markov process is solved by the method of stages. A longwall mining system is analysed as an example.

Jan 4, 1993

By Ellsworth Daggett

In the first paper on the Russell process presented by Mr. Stetefeldt, in May, 1884 (Transactions, xiii.), the process was treated from a purely theoretical standpoint.. 111 his second paper of October, 1886 (Transactions, xv,), the details of the plant, the chemicals used, and the manipulation in both mill and laboratory were treated. The aim of the present paper is to present economical results recently attained, new data affecting the preparation and manipulation of ore in the mill, and a more complete and systematic scheme of laboratory work. This paper is compiled mainly from Mr. Russell's notes of his own experience. Many of these notes, particularly those relating to work at Cusihuiriachic,* Mexico, have been upon work directly under the personal observation of the compiler, who takes pleasure in thus presenting to the Institute, data and considerations of much interest and value pot only to users of the Russell process, but to mill men generally. The description of the chemicals used and of the preparation of the mill-solutions being' in part the same now as when Mr. Stetefeldt's second paper was published, some use is here made of portions of that paper. No theoretical matter is here given. For a treatise containing also the theory of the process the reader is referred to Mr. Stetefeldt's complete work on " Lixiviation of Silver Ores by Hyposulphite Solutions," now in preparation. To facilitate the consultation of this paper, the following synopsis and index is prefixed. The figures in parenthesis indicate the page of this paper on which the subject is treated.

Jan 1, 1888

By Miguel Reyes, Bruce Whisner, Joseph Bickson, Lincan Yan, David Yantek, Justin Srednicki, Nicholas Damiano, Eric Bauer

Built-in-place (BIP) refuge alternatives (RAs) are designed to provide a secure space for miners who cannot escape during a mine emergency. Heat and humidity buildup within RAs may expose miners to physiological hazards such as heat stress. To minimize the risk of heat stress, Title 30 Code of Federal Regulations (CFR), or 30 CFR, mandates a maximum allowable apparent temperature (AT) for an occupied RA of 35 °C (95 °F) (MSHA 2008 [1]). The National Institute for Occupational Safety and Health (NIOSH) has conducted extensive research on the thermal environment of occupied RAs intended for use in underground coal mines. NIOSH research has demonstrated that a fully occupied BIP RA can exceed the AT limit by > 5.6 °C (10 °F) in mines with elevated mine strata and air temperatures (Bissert et al. 2017 [2]). In this circumstance, an RA cooling system could provide a solution. This paper provides an overview of test methodology and findings as well as guidance on improving the performance of a cryogenic air system prototype by optimizing the flow rate, increasing the tank storage capacity, and improving the efficiency of the heat exchanger of the cryogenic system. This may enable BIP RAs to meet the 35 °C (95 °F) AT limit in mines with elevated temperatures. The information in this paper is useful for RA manufacturers and mines that may choose to implement a cryogenic air system as a heat mitigation strategy

By J. F. McCoy

As mining develops into deeper and hotter regions, the safety and health of miners require that the workspace be cooled. Toward this end, this program has successfully developed a high performance, low maintenance spray cooler of 5000 cfm nominal capacity. Further, a series of four 25,000 cfm, nominal capacity, spray coolers has been built and mine tested with satisfactory results. The smaller coolers have been patented and become commercialized with 50 units currently in service. The concept has been developed independently overseas with an unknown number of units in operation.

Jan 1, 1984

By John E. Bailey

The advent of Nuclear Energy has caused a phenomenal growth in the uranium mining industry. To keep abreast of this surge the mining industry has located many ore bodies, determined the best types of mining adaptable to this particular type of ore and developed a highly specialized type of operation. But, has the mining industry gone far enough in the planning? Has ?built-in? safety been included in the efficient methods of operation? Preplanning safety in the mining industry, as in all industries, takes engineering and ingenuity combined with the experience and cooperation of all concerned. A system of mining can be planned on a map and it will look good. However, when the actual mining takes place, conditions may be such that deviations from the original plans may be required because of excessive water faults or other conditions encountered. With safety we may also be required to change, to conform to the characteristics of a particular operation. People in the mining industry are well aware that loose back has killed miners each year. This condition occurred in practically all types of mines. The condition is not new to us. It is also known that explosives, haulage, machinery and conditions common to all types of mining have taken a heavy toll of human life in mining. In addition to these hazards in the uranium mines, the hazard of radon is also present, Radon is a radioactive gas liberated from ores containing radium. This gas is released into the active workings by the blasting or breaking up of the ore. Sometimes it is caused by radium contaminated water seepage from abandoned workings or from the ore body itself. Until the action of this gas on the human was known, many miners were affected. Un- less adequate precuations are taken to protect the people in these mines,, they may be exposed to this hazard, Health researchers made a study of this substance to determine how it would affect the health of the men, They also studied men who had worked in previous years, in mines known to have contained radioactive materials. All of this research contributed to the present knowledge of radon and its daughter products. It is not flammable nor explosive, but, if allowed to enter the body through the respiratory organs it can cause serious damage. Mines have been operated in the past and are still being operated, which were known to contain explosive and noxious gases, indicating that this problem can be controlled. Several states have instituted laws that make it mandatory to provide adequate ventilation and use of monitoring devices to limit radon and its daughter products to a maximum of 300 micro-microcuries per liter of air. This is considered a safe limit for sustained periods of human exposure. While the findings of research do not prove conclusively that the inhalation of excessive radon or its daugher products cause lung cancer, indications point to this as a possibility, particularly radium A and radium C1 of the daughter products. The threshold limits set by law in most uranium producing states are believed to be safe. In a few years, when tests and data now in the process of collection by interested state officials and laboratories is complete, these limits may be found to be ready for revision. Studies such as these take time. At present, the limits that are used are based upon estimates. The permissible limits of exposure to radon and daughter products include a large safety factor. It is considered that a good supply of fresh air delivered to the working places, adequate dust control, the sealing of unused or abandoned workings, the removal of mine water which is generally contaminated and a safe waiting period after blasting, will hold to a minimum the dangers from this source. There are, of course, problems accompanying each of these procedures. For example, the ventilating of untimbered raises and bringing fresh, uncontaminated air to the working places may be a problem. However, a good mining man can solve these problems as they apply in each particular operation. From the information available at the present time, the daughter products containing polonium and emitting alpha radiation, may be a health hazard. Fortunately, the half life of most of the daughter products is short, however, radium D has a half life of 22 years and presents a problem of contamination in the storage of old tailings. So we can see that failure to comply with the accepted good mining practices may have harmful effects on the health of miners. It is gratifying to note the interest in this potential hazard by the officials in the uranium ore producing states, who are making extensive studies and keeping records of the men who work in this type of mining. This all provide information necessary for preplanning safety. By contrast, little has been accomplished to control the injuries and deaths from some other factors connected with most underground mining operations. I would like to discuss briefly one of the hazards which take an annual toll in our underground mines, this is falls of back and walls. This problem or hazard is present, and will be

Jan 1, 1958

By R. T. Richins

Coeur d'Alene Mines Corporation (CDE) is a precious metals mining company. The company's three mining operations are located In Nevada and Idaho. Collectively, these mines (Rochester in Nevada, and the Galena and Coeur In Idaho) produced about 61,000 ounces of gold and more than 7.5 million ounces of silver in 1991. The company is currently planning the development of two major properties; the Fachinal gold-silver project in Chile and the Kensington gold project near Juneau, Alaska. Fachinal and Kensington hold encouraging potential to significantly expand CDE's gold production during this decade. The permitting process for these two distinctly contrasting environmental settings, project design requirements and regulatory/political circumstances provide the basis for a comparative analysis of licensing and permitting requirements, timeliness of the permitting process and costs in the U.S. and Chile.

Jan 1, 1993

By W. J. Taylor, T. D. Parris

"Over 90,000 feet of raise have been bored at International Nickel underground mining operations throughout the Sudbury District since the advent of raise boring in the early part of July, 1964. With a total of 10 raise borers on hand at this time, techniques have improved steadily since introduction at INCO mines. The first unit, designed for use in rock of low compressive strength, had to be modified and redesigned to cope with Sudbury Area Precambrian rock. As equipment and boring techniques improved, a specially designed machine for larger holes was developed and is now in use. More powerful units, with a thrust capacity of up to 750,000 pounds, are under investigation. Raises have been bored up to 84-inch diameter, and the changeover to 5- and 6-foot flat reaming heads with improved cutter design has increased performance substantially. As a result, 5-foot-diameter raises have been completed to a length of 750 feet and 6- and 7-foot raises to over 500 feet. Reference is also made to the drilling of over 23,000 feet of drainage and sand-fill holes, ranging up to 7% inches in diameter, with smaller underground rotary drill equipment.Finally, a look into the future indicates the need for further improvements in equipment design to permit economic boring of 7- to 8-foot-diameter raises in Sudbury Area ground types."

Jan 1, 1972

By Dennis J. Callaghan

This report is the result of information obtained from a review of related literature, personal inquiry and on-site examination of active surface coal mining operations. Four improved surface coal mine systems are described in detail and evaluated for feasibility, implementation requirements, environmental benefit and costs. Engineering feasibility emphasizes equipment availability, compliance to design requirements, practicality and industry rating. Implementation potential emphasizes immediacy, ease, acceptability and constraints. Special attention was given to environmental responsiveness, both with regard to the solutions to mined-land reclamation problems and to the concurrency of reclamation. Each system description includes a hypothetical model mine with a depreciation schedule, capital summary, estimated annual production costs, sales price computation, production and operating cost summary, and a sensitivity analysis of mine price to stripping ratio. A program plan and time schedule for demonstrating a selected mining system covers site selection criteria, mine data collection, criteria for controlling and budgeting costs and reporting findings. Ten additional mining methods and techniques are briefly described and evaluated. Common reclamation problems are listed and described. Sixteen state reclamation laws and regulations are abstracted. Sixty-nine references are listed in the bibliography.

Jan 1, 1976

"THE CONCEPT of energy as a commodity, while not entirely new, is not as widespread as the importance of the idea to this modern world would lead one to expect. The growth in the supply and use of energy over the past years has been tremendous, but our very closeness and familiarity have somewhat distorted the viewpoint, particularly of the younger generation. To many of us who remember the wonderful satisfaction of our first responsibility for directing two horsepower hitched to a farm cart or hay wagon, there still arises a feeling of some awe at the casual flick of the switch with which our sons and daughters summon to their convenience the service of some one hundred or more horsepower.Energy is the vital component of our existence and, no matter what contempt our day-to-day familiarity may •breed, it is wise to .pause from time to time and consider our national energy standing. Have we still capital in the bank? Are our expenditures wisely •conceived and well directed? Is provision being made for the years •ahead for the needs of our children and our children's children?"

Jan 1, 1953

By A. E. M. Warner, I. E. Hills, C. L. Harris

Since the late Dr. Keith Brimacombe, et al, performed tests at the now-closed Asarco Tacoma smelter and the Inco Copper Cliff Smelter on Peirce-Smith copper converters almost thirty years ago, many Pyro-metallurgists have investigated using the technology. To the best of the authors knowledge, except for shrouded tuyere technologies using substantial oxygen enrichments, the core idea of using high pressure air injection has not been implemented anywhere in the world. This paper reviews the fundamentals of this technology and summarizes the basic economic considerations. It also presents the circumstances of where and when high-pressure injection might be justified.

Jan 1, 2007

By Ta M. Li, Russell A. Carter

The first century of mining in northern Idaho's Couer d'Alene District will soon he drawing to a close. Like so many other great raining districts, it has been a period accompanied by a rich and colorful history. From its early days as a gold rush camp, the district has evolved into the leading silver producer in the US, but the going has not been easy: early-day labor disputes, the challenge of mining for profit in some of the deepest mines in the Western hemisphere, and the constant search for new reserves at great depths have taken their toll of mines-and miners-along the way. To these traditional mining problems have of late been added the burden of inflationary cost increases, pollution control, and reclamation. A recent visit to the district by MINING ENGINEERING, how ever, revealed that the deep commitment of the operating companies and the quiet competence and vitality of their engineering personnel are key factors in the continued prosperity of the district.

Jan 7, 1976

By A. Uiga

The U.S. Bureau of Mines funded a project which addressed objectives concerning irrigation of native plants and inoculation of native plants with vesicular-arbuscular mycorrhizal (VAM) fungi. The specific irrigation objectives were 1) to demonstrate the performance capabilities of solid-set irrigation for reclaimed mineland conditions, and 2) to demonstrate and evaluate three irrigation concepts under two separate water supply conditions. The VAM inoculations were to assess irrigation benefits in establishing VAM relationships for transplanted native species. Following the seasonal demonstration (May to September 1983) at 3 separate mine sites, conclusions were made that apply to the 6 state Western mining industry. The demonstration sites were located in Montana, Wyoming, and New Mexico. Positive conclusions were reached for 1) the use of soil moisture sampling with or without irrigation, and 2) the selection of solid-set sprinklers as the irrigation method. The conclusions about the irrigation concepts and strategy were mixed, due to the short-term (1 season) nature of the project. No conclusions could be reached for the VAM inoculations because the study time was too short.

Jan 1, 1984

By Jr. Goller

You and I can visit cement plants, inspect the various rotary kiln systems and find some equipment or some burning techniques that waste energy--fuel and power. After we have made such a visit and studied a few ideas, we could recommend ways to eliminate much of this waste. Probably every idea would cost money to bring into action. For our discussion, let us arbitrarily set an upper limit of $1,000,000 on the recommendations that we are allowed to make. Call these "low-cost" or "short-term" measures. They are improvements that do not require more than say, three months to complete; they do not require a major revision to the process. Other recommendations are "high-cost" or "long-term"; they are outside the scope of this discussion. Some of our "low-cost" recommendations would offer a satisfactory return on the money that they cost; the remainder would not. Now, is there some way that we can rather quickly pick out the "low-cost" measures that will show a satisfactory return and spend our time making these improvements first? Can we separate these items from those where the return is less likely to be good? I feel that we can pick some of these items quickly if we have a kiln system that has consistently non-uniform day-to-day operation. If the operation is uniform we probably cannot pick them quickly.

Jan 1, 1977

By William N. Hale

This Bureau of Mines report gives a detailed study of water usage in the Montana mineral industries, along with projections for the future. The mineral industry of Montana in 1963 used 36.5 billion gallons of new water, and reused or recirculated an additional 53.5 billion gallons for a total water requirement or usage of 90 billion gallons. The petroleum industry was the major water user, followed by the copper and zinc industries. Many mineral industry operators provide their own water, and new water is withdrawn largely from surface sources. At present, sufficient water is available in rivers, streams, and reservoirs in Montana; however, shortages do exist locally near mineral industry operations using large quantities of water. Some is supplied from sources up to 44 miles distant. New water withdrawn by the State of Montana mineral industry is expected to increase from 36.5 billion gallons in 1963 to 51.1 billion gallons by the year 2000. The total-water requirement is expected to more than double, or reach 182 billion gallons by the year 2000.

Jan 1, 1966