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By Thomas E. McNider

On July 20, 1990, a Spontaneous Combustion Control Plan was approved by MSHA for Jim Walter Resources, Inc. No. 5 Mine. The mine operated under the plan for twenty-nine shifts before MSHA revoked the plan. A total of fifty-five seals were constructed during the process of implementing the plan. The major difficulty in applying the control concept resulted from problems controlling leakage at the numerous seals. The number of seals was a direct consequence of attempting to merge the traditional bleeder system, used in all the Blue Creek Mines, with the bleederless system Jim Walter Resources proposed as a means of controlling the spontaneous combustion hazard. This paper discusses Jim Walter Resources experience with spontaneous combustion control and the new safety standard which applies to underground coal mines that demonstrate a history of spontaneous combustion and how this standard would apply to our No. 5 Mine. The new Ventilation Standards were published in the Federal Register on May 15, 1992, and scheduled to go into effect August 16, 1992.

Jan 1, 1993

By David Lunt, Paul Messenger, Peter Allen

The Rawas Gold Project in Indonesia has a high silver ore with a ratio of approximately 25:1 Ag/Au. Four process flow­sheets were considered during the development phase, ie. full Merrill Crowe, CIP, CIP with zinc cementation of eluate and a hybrid Merrill Crowe - CIP circuit. The process plant was constructed using a CIP circuit with zinc cementation of eluate. Unusual aspects of the design include an elution circuit designed to strip three batches of car­bon per day and an elution column designed to operate with either upward or downward solution flow. Significant improvements implemented since starting up the plant include the use of local materials and labour for relining the mill, a change from lime to caustic soda for pH modification and the elimination of caustic soda dosing to the elution pre-soak step.

Jan 1, 1998

By Bernie W. Martin, Paul MacLeod

The new St. Clair River International Tunnel Project presented unique challenges in planning, permitting and approval. The project straddles the border between the Province of Ontario and the State of Michigan necessitating the review of U.S. approval legislation that has not been used in 60 years. The preparation of an environmental impact report to satisfy the legislative requirements for the Federal laws of the U.S. and Canada as well as the Province of Ontario and the State of Michigan presented a daunting task. In all, over 200 external contacts were made in carrying out the environmental approvals and permitting work. The definition of the alternatives including the NULL option were documented along with the impacts and mitigation measures. A "Modified Delphi" technique, along with other methodologies, was used for alternative evaluation and selection. A formal and informal public consultation process was undertaken which involved over forty major presentations and external meetings. A unique alternative to the traditional design, tender, build contracting practice was adopted; The Negotiated Compressed Process (NCP).

Jan 1, 1993

By J. L. Waldron

This paper presents a theoretical tool used to analyze gold recovery problems at Dee Gold Mining Co. The first step in addressing the problem was realizing that lower gold extraction was linked to high silver grades, and could not be correlated to either the carbonaceous or sulfidic content of the ore. Analyses of metallurgical testwork, blasthole, and mill recovery data demonstrated that decreases in gold extraction correlatP� well to increases in silver extraction. Figure 1 illustrates this for 1991 mill operations. This was the starting point for the work described in this paper.

Jan 1, 1992

By Daniel W. Kappes

In late 1995 at the Randol symposium in Squaw Valley, I gave a paper which described the Itos project flowsheet. At that time, project construction was nearly completed and stmtup was close. This paper describes the ltos operation since then. To summa­rize things, startup occurred partially in late 1995 with full start­up of all components in about mid 1996. From then until now, April 1998, the plant has been running at partial capacity and has yet to achieve full production rates.

Jan 1, 1998

By Malcolm Roberts

Extensive personal experience in the USA and Australia has shown that Australians working in suitable work environments are capable of world class performance. To build such work environments, mining leaders need to ditch two common management approaches that have not succeeded. Firstly, stop relying on traditional methods of trying to change people's behaviour simply by using communication alone to change attitudes and then change behaviour. Analysis of human behaviour explains why this approach fails in all industries. Secondly, stop trying to improve productivity by just running harder and increasing capital investment. Understanding work processes explains why this approach has limited success. These two approaches underlie problems commonly mentioned by many Australian mining executives: • negative or inadequate attitudes prevailing among Australian miners and managers including the lack of ownership of business goals among people at many levels • inadequate development of managers and accountability • lack of a competitive advantage in an industry in which labour costs are around 50% of mine site cash costs at many mines, and, • logical, emotional and physical barriers to change.

Jan 1, 1995

By Dean S. Rogers, R. A. Metz

The conventional role or exploration, development and grade control is examined in this paper within the context of the many and varied types of gold occurrences which are found at the Dome Mine. The account endeavours to trace the development of the total ore evaluation process, from diamond drilling through the exploration and drifting stage, to the stope development and planning phase of the operation, with an emphasis on sampling techniques and assaying procedure. The concept of ore reserve calculations is developed and the practice of grade control is described. In summary, the role of the geological, the engineering and the mining department is presented in relation to the contribution each has to make in the evaluation and exploitation of ore from one of the world's classic Archean gold deposits.

Jan 1, 1992

By Dani Delaloye, Kas Zurek

Evaluating and selecting the appropriate excavation method is a key to the success of any tunnelling project. The benefits and risks of different methods should be well understood by the designer and communicated to the project owner to enable selection of a preferred method from a technical, social and environmental impact, cost and constructability perspective. For tunnels that have an internal diameter around 3 m, depending on the tunnel purpose and ground conditions, both microtunnelling with pipe jacking and tunnel boring machine excavation with a one- or two-pass lining may be feasible construction methods. Using the Ferry Road and Riverbend Combined Sewer Relief Project located in Winnipeg, MB as a case study, this paper will discuss the benefits and drawbacks of each method, including technical design, social, environmental, cost, schedule, and risk considerations.

Jun 13, 2023

By L. E. Allen, J. F. Abel, D. R. Morgan

The Waste Isolation Pilot Plant (WIPP) is a geologic repository for disposal of transuranic waste and is operated by the U.S. Department of Energy (DOE). The repository is located at a depth of 655 m in the Permian age salt beds of the Salado Formation, 40 km east of Carlsbad, NM. A key component in the design of the WIPP repository is the installation of concrete structures as panel seals in the intake and exhaust drifts after a panel has been filled with waste containers. The DOE has proposed several panel closure design modifications to the EPA. EPA approval of the changes is required since the details of the designs are specified in EPA’s final rule as a condition for WIPP certification. The Environmental Evaluation Group, in its role of providing technical oversight on the WIPP project, has evaluated the proposed modifications. An analysis of this evaluation is discussed.

Jan 1, 2003

By Melvin A. Jennings

Even though the title of this paper is quite long, the ideas presented herein are very simple. In fact, it occurs to me to be somewhat humble about coming before such a distinguished group with such a simple presentation. However, the application of these ideas has proven useful in at least two copper flotation plants. The purpose in presenting this paper is to inspire some interest in the great stores of data chat the Mining Industry often accumulates without making any attempt at analysis. Unfortunately, many milling engineers rely rather heavily on percent recovery as a strict measure of a concentrator's relative performance. The fallacy of this reasoning is not difficult to see since, by definition, percent recovery is a function of feed assay, tails; and concentrate grade. If copper tailing is constant, and it very nearly is for a strictly sulfide copper ore, percent recovery must fluctuate almost directly to the feed assay. The point that I wish to make here is that it is very seldom justified to compare the percent recovery figure from one period of time to another without considering the difference in feed assay. The problem of comparing results is even further complicated when the ores are of mixed oxide and sulfide mineralogy.

Jan 1, 1978

By L. Alan Weakly

The purpose of this paper is to present a viable method of reinforcing rock pillars by utilizing fully grouted reinforcing steel and a cement - fly ash mortar. Although the fully bonded bolt concept is not new as exemplified .by the present widespread use of resin bolts within United States mines and by the use of cement grouted reinforcing used as back pins in the Kiruna Iron Ore Mine in northern Sweden, (1)(2) the method of stabilizing mine pillars with fully bonded reinforcing is new. This method, called the "grout-rebar system", was first incorporated at St. Joe Minerals Corporation's Fletcher Mine in December of 1972. The system was used on an emergency basis before extensive research on the mechanics of the system could be completed. Since December of 1972, however, approximately 206 pillars have been reinforced at Fletcher and the system is currently being used on a regular basis at two other St. Joe mines and at two competitor mines in the area. Basically, this paper is a case study of the efforts, research and results of utilizing the grout-rebar system, on a selective basis, at the Fletcher Mine. In addition to information about the system, this paper will explain in detail the three rock mechanics instruments developed by St. Joe and used to measure and monitor rock movement to validate the grout-rebar system.

Jan 1, 1976

By S. V. Krishnan

In the upgrading of finely-disseminated iron ores, selective desliming is the critical step which must be controlled in order to achieve efficient flotation. A prerequisite for selective desliming is a properly-dispersed pulp; sodium silicate is commonly used as a dispersant. The mechanism by which sodium silicate acts as a dispersant in the presence of calcium ions was examined by streaming potential measurements, settling tests, abstraction density determinations, selective flocculation tests and scanning electron microscope observations. The study established that calcium silicate precipitates on the mineral surfaces dispersed the pulp. Although sodium silicate was a nonselective dispersant, the addition of corn starch aided the flocculation of goethite over quartz at low silicate additions, but became ineffective at higher silicate levels. A model is presented to explain the dispersant mechanism of sodium silicate in the presence of calcium ion for selective flocculation of iron ores.

Jan 1, 1982

By T. M. Yegulalp

One of the important factors affecting the determination of the minimum number of increments in a gross sample of coal is the variance component due to segregation. The segregation variance may be estimated by following the ASTM standard procedures. Since the estimate itself is a random variable, it is important to test if the value obtained is due to chance causes. This paper introduces a statistical test, based on the procedures published by ASTM, to test if the segregation variance is significantly greater than zero.

Jan 1, 1986

By Willard C. Lacy

Discovery of a mine is a complex affair. No mine is simply found but comes about through the efforts of many. It is difficult to establish "credit" when a mine is found and becomes a viable operation, or "guilt" when a mine is lost, goes bankrupt, or remains undeveloped. The story of the Toquepala and Cuajone developments entails various stages of: (1) discovery and recognition; (2) testing and innovation; (3) political and industrial negotiation and intrigue; and (4) finance, development, and operation. The Toquepala and Cuajone projects introduced innovative drilling techniques, were among the first major porphyry copper deposits to utilize induced polarization (1P)geophysical methods, were among the first deposits to undertake complete feasibility studies on drilled- out ore bodies, and were developed by the first large Western Hemisphere copper mining consortium. Many persons have contributed to the development of these two great deposits. Some of the names have been lost and certain contributions have gone unrecognized. I apologize for these omissions.

Jan 1, 1991

By M. Li, J. K. Thompson, A. S. Azman

"Powerful mining systems typically generate high-level noise that can damage the hearing ability of miners. Engineering noise controls are the most desirable and effective control for overexposure to noise. However, the effects of these noise controls on the actual hearing status of workers are not easily measured. A tool that can provide guidance in assigning workers to jobs based on the noise levels to which they will be exposed is highly desirable. Therefore, the Office of Mine Safety and Health Research (OMSHR) of the National Institute for Occupational Safety and Health (NIOSH) developed a useful tool to estimate the hearing loss due to occupational noise exposure in a systematic way and evaluate the effectiveness of developed engineering controls. This computer program is based on the ISO 1999 standard and can be used to estimate the loss of hearing ability caused by occupational noise exposures. In this paper, the functionalities of this software are discussed and several case studies related to mining machinery are presented to demonstrate the functionalities of this software. INTRODUCTIONPeople regularly exposed to noise can develop hearing loss at different levels of severity depending on a number of factors. The resultant hearing loss can affect one’s ability to understand speech, learning, acoustic signal perception, or appreciation of music. Hearing loss caused by overexposure to noise has long been recognized in literature. However, it still does not get serious attention by those working in noisy environments because the loss of hearing ability is a gradual process and workers are often unaware until the damage becomes an apparent problem. In the United States, occupational hearing loss is one of the most common work-related illnesses. Depending on the definition of exposure and impairment, in 2012 the National Institute for Occupational Safety and Health (NIOSH) estimated that there are between 5 and 30 million workers in the U.S. who are exposed to noise levels at work that put them at risk of hearing loss.4 In the mining industry, noise-induced hearing loss (NIHL) is particularly severe due to the fact that heavy-duty machinery is widely used to improve production efficiency, and this machinery can generate much higher-level noise than the permissible level defined by regulation. As a result, the mining sector has the highest prevalence of hazardous workplace with high noise exposures (76%) among all industrial sectors."

Jan 1, 2015

By Richard Klimpel

1. Introduction Laboratory and industrial grinding tests have shown that the process of size reduction can be significantly influenced by chemicals added to the powder or slurry being ground. The terms grinding aid or grinding additive refers to a substance which when mixed into the mill contents causes an increase in the rate of size reduction. The increased rate can be used to grind a higher feed rate to the desired product size or it can be used to produce a finer product size at a fixed feed rate. Whether the use of a grinding aid is justified in any given situation depends on the cost of the substance versus the improvement of output or product quality obtained with its use. Obviously, an expensive chemical must be effective in very small concentrations if it is to be economically justifiable; the cost criteria is calculated on the basis of the cost of the grinding additive per ton of material ground. Although there is direct experimental verification of the advantageous effect of grinding additives, no sound scientific explanation has yet been offered which explains or predicts the general behavior of additives. Rose and Sullivan have summarized most of the work undertaken prior to 1950 and Hartley, Prisbrey, and Wick have recently prepared an updated synopsis of the grinding additive literature. Many of the studies reported consist of subjecting materials with simple geometric shapes to some type of hardness or controlled single fracture test. On the other hand, a number of the studies were carried out on operating industrial scale mills, with little control or precise monitoring of the effect of the additives.

Jan 1, 1977

By M. G. Schulz

Mining of molybdenum at Questa, New Mexico has been accomplished by block cave methods since August, 1983. As caving progresses, a periodic geologic evaluation is made of the rock-types present in finger raises on the Grizzly Level of the mine. The production maturity of the cave can be monitored by relating this data to geologic cross-sections through the ore body. The draw point mapping program is a simple and effective tool that is used in making draw control decisions at Questa.

Jan 1, 1985

By A. Arik

1his paper presents a modified ordinary kriging technique referred to as the "Nearest Neighbor Kriging" (NNK). The method is a simple and practical tool to use when the ordinary kriging (OK) results are unreasonably smooth, especially when estimating recoverable ore reserves for deposits with skewed grade distributions. NNK is robust and globally unbiased like OK. However, it is more advantageous over OK because it can control some of the smoothing and conditional bias which have been the major pitfalls of OK in many grade estimation cases. The paper details the methodology of NNK and its application to a gold deposit.

Jan 1, 1998

By M. Hardy, K. Nielsen, M. Ramey

American Soda, LLP has commissioned the first solution mine for recovery of naturally formed sodium bicarbonate (nahcolite) from low-grade deposits using high-pressure, high-temperature injection fluid. This project, known as the Yankee Gulch Project, was commissioned33 years after discovery of the deposit and followed an intensive four-year feasibility study that included a full-scale pilot test. The nahcoliteis co-mingled with oil shale and is impermeable. Solution mining is achieved by a combination of thermo-mechanical cracking and dissolution. Elevated temperatures are required to initiate the thermally induced cracking and to enhance solubility of the nahcolite, which is highly temperature dependent. This paper will provide an overview of the development of the project from discovery, characterization, pilot testing, permitting and commissioning, with emphasis on the solution mining aspects.

Jan 1, 2003

By Alvin W. Schillinger

Drilling was not entirely satisfactory in the search for native copper in the Osceola amygdaloid footwall as mining showed oreshoots to be more continuous than drilling indicated. The Geophysics Department of Michigan Technological University developed a portable induced polarization drill hole probe with a 3 electrode configuration and a sampling radius of 5'± A 20 ma current of alternately reversed polarity is pulsed at 3.5 sec. intervals and readings are taken every two feet. Potential is read during the "on" cycle for resistivity determinations. During the "off" cycle, after 10 ms delay, the I.P. potential is sampled for 10 ms and recorded. Resistivity (ohm-feet) and "S" values (mv/v) are plotted on semi-log paper. A lithologic log is plotted based on resistivity and anomalous "S" values noted. The low resistivity amygdaloid contains sills of high resistivity basaltic trap. Verified by core logs, amygdaloid-trap contacts could be picked to ±.5' from resistivity alone. Lithologic logs of long steel holes, based' on resistivity, now replaced sludge logging. An "S" value of 30 mv/v was established as the lower limit of diagnostic I.P. effects in mineralized amygdaloid and 50 mv/v as a threshold value for ore. Of 914 footwall zones drilled, 315 were probed yielding 203 anomalies. Success increased from 34% for drilling to 72% for drilling and probing. As checked by mining, 46 probe results were 78% correct. Failures were due to the instrument not detecting copper or to the misinterpretation of an anomaly. No false anomalies were found.

Jan 1, 1964