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By James E. Palmer

Geologic constraints on mining and recoverability include the following: coal seams too thin or thick for conventional mining methods; coal seams with insufficient stratigraphic separation; unstable roof or floor strata; discontinuous or lenticular seams; coal seams that have high dips or are intensely faulted; water problems due to proximity of aquifers; and coal quality problems such as excessive sulfur, ash, chlorine, sodium, etc. The demonstrated reserve base for western coal of 220 billion tons is considered misleading as it does not adequately incorporate the above parameters in estimating procedures. Current reserve base estimating procedures involve an abstraction of data from generalized resource estimates. The authors believe the reserve base should be determined independently beginning with well-known deposits, with all mining and recoverability constraints fully incorporated.

Jan 1, 1981

By J. P. Ducarme

The eastern U.S. contains vast reserves of thin seam coal deposits, particularly in the Appalachian mountain region. These typical 355 to 710 mm thick reserves are difficult or uneconomical to recover with present technology. The U.S. Bureau of Mines is developing technology that would allow nearly 100% recovery of thin seams in these mountaintop regions. This paper details the research that has been conducted on these new techniques and presents results of testing on a cross-ridge full-scale physical model.

Jan 1, 1994

By P. Somasundaran, J. T. Kunjappu

Spectroscopic techniques are becoming increasingly popular for characterizing the interior of adsorbed layers of surfactants and polymers at solid- liquid interface as well as in the identification of com- pounds on mineral surfaces. This review encompasses the application of fluorescence and ESR spectroscopic techniques to reveal the microscopic environment of the adsorbed layers of surfactants and polymers on minerals with a special reference to the adsorption of anionic surfactants (e.g., sodium dodecyl sulfate) and polyelectrolytes (e.g., polyacrylic acid) at positively charged mineral (e.g., alumina) - water interfaces. Finally, the utility of XPS and auger techniques to identify the surface elemental composition of different mineral species has been related to their flotation efficiency.

Jan 1, 1987

By R. L. Peyton

Risk analysis is used extensively in many engineering applications. Although its use in the field of dam safety has been limited in practice, it has received considerable attention in recent years in the dam safety literature. Thus far, it has been shown that risk analysis in the evaluation of existing dams has the potential for providing a more rational basis for decision- making because of its focus on the direct issues--likelihood of failure, likelihood of loss of life, and risk cost of damages. It provides for a logical balance between the risk a dam imposes and the degree to which rehabilitation is required, compared to traditional evaluations based on somewhat arbitrarily chosen design events applied to large classes of dams. Dam owners could benefit by optimizing the cost of remedial measures. Downstream landowners could benefit by minimizing the likelihood of flood damages. However, it is also clear that significant technical and policy issues remain to be resolved before risk analysis in dam safety is accepted and routinely implemented in engineering practice. An obvious and important potential application of risk analysis is its use by the state regulatory agency as an in-house evaluation tool, or even as part of regulatory policy, in the implementation of its state dam safety program. Adoption of such a policy would have an important impact on the mining industry. .Although no state dam safety programs are known by the writers to have officially incorporated risk analysis into their regulations, there appears to be considerable interest in the concept. In recent surveys 47 states agreed that the development and promotion of a risk assessment methodology for state dam safety programs should be encouraged (Tschantz, 1983; Tschantz, 1984). The issue has also received important attention within the Association of State Dam Safety Officials (1986). One state-Illinois-proposed regulations during 1986 to allow risk analysis to justify lower spillway requirements for existing dams (Illinois Department of Transportation, 1986). At the Federal level, the National Research Council has found risk analysis especially appropriate for assessing dam safety at high-hazard dams (National Research Council, 19851, the Bureau of Reclamation has published guidelines for incorporating risk analysis into their dam safety grogram (U.S. Department of the Interior, 1986), and the Federal Emergency Management Agency has recently sponsored workshops and supported research related to risk analysis in dam safety (Federal Emergency Management Agency, 1985a ; Federal Emergency Management Agency, 1985b; - - McCann, et. al., 1985a, 1985b).

Jan 1, 1986

By Stuart Ratcliffe, Denis Kidby

The development of Vitrokele™ Technology over the last 10 years is reviewed with reference to mine site piloting and com­mercial applications. The first mine site piloting was conducted in Australia in 1989 followed by a further six continuous site trials in Australia, Canada and the USA. These major pilot plant studies are complemented by over 50 laboratory scale batch and pilot testwork programmes. The first commercial plant using Vitrokele™ Technology was the Connemara project commissioned in Zimbabwe in 1995. Subsequent to this, three commercial scale projects have been designed using Vitrokele™ to recover precious metals, base met­als and cyanide. The various projects are discussed with relation to the differ­ing flowsheets applied to each particular case.

Jan 1, 1998

By B. A. Firth

The presence of misplaced ultra-fine particles has been shown to decrease the separation efficiency of unit operations used in coal preparation. Although the classification of fine coal was considered to be adequate for the needs of the coal industry during the 1970's and 1980's, it has become apparent that further improvements in the yield/ash/moisture relationship achieved by coal preparation plants will require increased efficiency in this size separation step. This paper describes the issues which are evolving in this area, and the capability of current and developing techniques to address the problems which need to be overcome.

Jan 1, 1996

By K Timtner

As shown in former publications there are problems in load sharing of backstops in multiple drives of conveyors. Therefore, detailed calculation methods and design recommendations are required. In this paper various designs of load sharing methods are described and a dynamic torque calculation method will be presented. With this method the loadsharing properties for low and high speed backstops are calculated and compared. These properties depend on the spring characteristic of the drive train between backstop and load. Furthermore, the properties depend on the method of torquearm support and shock absorber configuration. Remarkable differences for external and internal backstops are shown

Jan 1, 1998

By W. Fletcher

Startup of a new plant is a very interesting time. It generally is also a very demanding and often frustrating period. Startup problems can become serious ii they impede the early achievement of full plant production. Raw materials are wasted, manpower is unproductive, field modifications can be extremely expensive and market commitments may not be met. This paper outlines a well proven and highly successful approach to eliminating many of the problems and frustrations often experienced in plant startup. The procedures and methods summarized in the following paragraphs have been developed over a period of 25 years during which some 90 plants were started up.

Jan 1, 1981

By P. C. Schmall

Ground freezing has been used for the sinking of deep mine shafts for more than 140 years. While advances in refrigeration technology have refined the overall freezing operation, the basic ground freezing concept remains the same. This paper presents an overview of the ground freezing process and the unique advantages that ground freezing brings to shaft construction. Design and construction considerations, including instrumentation and monitoring, are discussed. Case studies are presented to illustrate ground freezing applications for mine shaft installation.

Jan 1, 2010

By Russell L. Wood

The title of this session seems to have been picked especially for this paper. It is 1984, it is the morning after, and there is one monumental hangover among many if not most of the oil companies that have invested in mining in the past decade or so. How an oil company looks at mining depends on what time period you are talking about. A few years back around the time of investment this is what they were probably looking at: 1. A balance sheet of their own that was beginning to go wild, with many of their commodity prices having already seen increases of two, three, or four fold, and with no end in sight. 2. A need to invest their earnings someplace fast before the stockholders or the government got too interested. And that someplace should be in an industry where their own management skills could be applied. (Only a true cynic would suggest that this is a form of job security) 3. In mining there was an industry amazingly similiar to their own, one working with non-renewable natural resources, dealing with the same types of government agencies, and having the same type of critics and pressures from the general population. 4. An industry that was somewhat backward as compared with their own, and one where a generous ration of the capital and management skills so handsomely bestowed upon the oil industry could be used to great advantage.

Jan 1, 1984

By Peter J. Szabo

Introduction There has been much said recently about the sophistication of Japanese management in turning out reliable, inexpensive products, such as cars and steel. Techniques include consensus management and quality control circles. These have been touted as prime reasons for inexpensive Japanese products. An often neglected, but major factor in the equation of cheap export goods is the role played by Japanese trading companies. These venerable institutions are a vital factor in Japan's overall strategy of keeping the price of raw materials at the absolute lowest levels. This is critical to the country's economy since the nation must import more than 85% of all its coal. A country that is so desperate for imported raw materials would appear, at first glance, to be at the mercy of its suppliers. In Japan's case, however, the opposite is true. With the exception of brief' windows in 1974-75 and 1980-81, Japan has been in the driver's seat in negotiating contract terms. Due to its dominant role in world coal trade, Japan's situation can be described as a de facto monopsony. By definition, a monopsony is a market situation where the product, in this case coal, is offered by many sellers, but is sought by one buyer. This has been due to the role of Japanese trading companies in dealing with suppliers. Table I depicts trading companies by size in 1982. Mitsubishi and Mitsui are overshadowing in terms of size. The others, though less significant, play a vital role in orchestrating the marketplace. Three critical building blocks on which the strategy of the trading companies are based include intelligence networks, exceptional training of company traders, and shrewd contract negotiation practices. Intelligence Networks All success is derived from these three key components. Of the three blocks, intelligence gathering is the most important. With all the sophistication of the Central Intelligence Agency, the Federal Bureau of Investigation, Interpol, and the Surete', the Japanese trading company's method is every bit as competent and far more gentlemanly. Friendly competition is the key to survival. Although one Japanese trading company appears to be in ardent competition with its rival Japanese trading companies, when studied closely, a totally different picture emerges. The end user nominates certain trading companies as market channels and informally guarantees they will receive compensation regardless of which company wins a specific order. With this concept in mind, the pressure is off. The trading company can aim at getting the best price for the end user. Therefore, bargain, beat, and share information. Do whatever is necessary, but get the lowest price for the end user. Even with the game so gentlemanly, no victory could be assured without an adequate intelligence network. Proper intelligence is only as good as the sources drawn from. But how is one assured of getting the right information? The answer is verification. Verification is comprised of numerous independent sources each cross checked at a central processing unit in Tokyo. Each major Japanese trading company receives input, not only from its own trader, but from other trading companies as well. In addition to their own compilation, trading companies rely on the The Coal Manual, published annually in Tokyo by TEX. This manual covers every major coal producing country. Mines are located and seams identified, mining recovery, equipment lists, washing yield, railway distances

Jan 1, 1985

By Richard L. Ash

Usually stresses generated by explosive charges during blasting are considered to propagate through materials in a spherical manner. Although conical stress-waves had been suggested by a few investigators they have never been clearly defined or critically observed. An experimental technique using models and lengths of Mild Detonating Fuse was developed to produce conical stress-waves and study their effects. Several materials with different properties were tested to compare the influence of those properties on wave shape and crater formation. The investigations showed that whenever column charges were end-initiated, conical stress-forms were produced if the explosive's velocity exceeded the energy propagation velocity of the surrounding material. The stress-cone angle significantly affected fragment size and shape as well as the geometry of craters produced.

Jan 1, 1967

A PDP 11/34 computer has been inter- faced to existing instrumentation in a 400 tph rod-mill/ball-mill grinding circuit and programed with a Kalman filter to estimate several unmeasured variables. A dynamic two-size- fraction model of the circuit is used to predict the complete state of the circuit including particle size distributions around the circuit, mass holdups and flowrates, the ball-mill grinding rate, water additions and cyclone parameters. Online measurements of sump level, slurry densities and product particle size are used to update the model values sequentially on a 20-second interval. This procedure results in optimal estimates of circuit variables given the relative reliability of measurements and the accuracy of the model.

Jan 1, 1983

By C. S. Davis

In being asked to present this paper on the improvements in loading and hauling equipment and the effect on unit costs, Mr. Van De Water, your program chairman, stated that his reason for coming to a contractor was due to the wide experience of, and I quote: "a large contracting firm using a variety of equipment on varying types of earth moving jobs." We people in Utah Construction Company are flattered that Mr. Van De Water singled out our Company for this assignment. Utah Construction Company's participation in open pit mine stripping antedates the 1920's, when overburden was being removed from copper ore in Bingham Canyon, Utah. Our first stripping con¬tract for the Copper Company was finished in 1912. Since that early beginning, Utah has, as a contractor, been engaged to strip and mine iron ore properties, coal properties, copper properties, uranium properties, phosphate,-gypsum, limestone and dolomite properties. And, as you know, the Company has become a major producer of iron ore from Company-owned open pit mines. Utah Construction Company has been instrumental in the evolution of open pit mining tools. Some of the first tools were the old wood and coal fired stream shovels which had to be fired hours before a shift started to insure a full head of steam, providing power to excavate with the then large 1-1/2 cubic yard buckets. Today, Utah's strip mining is done, with 18 cubic yard and 10 cubic yard crawler shovels. Yesterday's horse and mule drawn, iron wheeled wagons, with 1 and 2 cubic yard capacity, which were hand dumped by removing the false bottom, one 2 x 4 at a time, have been replaced by today's- 50-ton capacity, hydraulic, rear dump trucks and giant 40-ton coal haulers. Utah Construction Company used the early fresnes and wheeled scrapers which were horse and mule drawn. Often, an operator holding too tightly to a handle was thrown into his horses when a hard spot turned the scraper, a contrast with today's 20 and 25 cubic yard, self-powered diesel and diesel electric Gargantuan rigs; with power controls that relieve the operator of practically all physical work. This Company has pioneered many of today's advances in equipment with shop made prototypes, features of which were adopted and elaborated upon by equipment manufacturers.

Jan 1, 1959

By J. Y. Hwang

Coal cleaning with traditional magnetic separation usually yields unsatisfactory results because minerals associated with coal, such as quartz, clay, pyrite and calcite, are weak-or non-magnetic. Magnetic reagent technology is a new mineral processing technology with the capability to enhance the magnetic property of minerals selectively. This reagent can be adsorbed selectively on minerals through the control of surface chemistry and, thus, result in selective magnetic enhancement. The application of this technology on coal cleaning has been experimentally demonstrated. Good separation results can be obtained at low to medium magnetic field strength. Comparison with other processing technologies is included.

Jan 1, 1992

By Charles Banks Belt

In 1925, Niggli (1925, pp, 1-69), formulated a physico-chemical, explanation for the origin of hydrothermal ore deposits, from a concept that had appeared earlier in the literature in the writings of Von Groddeck, Stelzner, Beck, de Launay, Kemp, and Lindgren. Niggli proposed that pressure at depth could force volatiles from deep-seated magmas. The volatiles would In turn form pegmatites and then ore deposits as the fluids cooled. This is one view of a general theory of ore genesis that gained secondancy for years among such prominent geologists as Fenner (1926, p, 697) and Emmons (1936, pp. 29-70). It was, proposed that ore deposits were precipitated from solutions or fluids that had escaped or been separated from a deep-seated magma by means of liquid immiscibility or crystallization or gas transfer. This theory is based on the presence of igneous rocks close in space and age to hydrothermal ore deposits in many mining districts of the world. As is well known, there are many ore deposits apparently of hydrothermal origin that are neither spatially nor chronologically related to igneous rocks, In still other localities where there are no hydrothermal ore deposits, igneous rocks occur that are similar in composition to those in mining districts. In view of such facts, the applicability of the Niggli theory to all hydrothermal ore deposits may well be questioned. The chief purpose of this paper is to test the Niggli theory by studying the primary petrology, hydrothermal alteration, and distribution of copper and zinc in silicic igneous plutons supposedly genetically related (in the Niggli sense) to nearby hydrothermal ore deposits, Silicic Tertiary plutons in three New Mexico mining districts were chosen, the Hanover-Fierro intrusive at Hanover and Fierro, the Granite Mountain pluton at Magdalena, and the four outliers of the Lordsburg stock at Lordsburg. First, it had to be established whether the observed plutons were or were not the source of the adjacent ore deposits. This was done by studying the relation between the copper or zinc distribution-and the primary or secondary features in the plutons studied, and the time relations between instrusion and ore deposition. Primary igneous features of a pluton are defined as the minerals, texture, shape, and character of the pluton which were formed prior to the complete solidification of the rock, secondary features include all changes that took place in a pluton after solidification. They are identified by their cross cutting nature or as replacing primary minerals, Under the Niggli concept, it is proved that the ore ions did not originate from the parts of the pluton now visible as immediately adjacent to the ore deposits; it must then be established, if possible', that the ore ions were separated from deeper parts of the intrusive, Some idea as to whether the copper or zinc ions originated from a related magma at depth may be gained by a comparison between the primary (that is, pre-alteration) zinc and copper abundances found in ore localizing intrusive studied and the average abundances for copper and zinc in silicic igneous rocks most recently given in the literature. Finally, the relation between ore deposition and hydrothermal alteration was studied on a regional as well as on a local scale.

Jan 1, 1958

By Charles E. Dunne

One of the most frequently asked quesitons is: "Where is copper (price and usage) going?" I will not attempt to forecast either the future price of copper or the future growth of the copper industry; rather I would like to discuss the current trends experienced in the smelting and refining terms and conditions for sales and/or purchases of copper concentrates. A brief review of contract language and terms, together with a review of the common jargon, I believe, would be helpful. To accomplish this review, I will first list what I consider the four basic parts or sections of a basic ore contract and then illustrate basic terms with calculations.

Jan 1, 1984

By Luis R. Bittencourt

Research efforts have been made to characterize a refractory Brazilian bauxite ore composed basically of gibbsite, kaolinite and quartz. Detailed polished-section microprobe analysis of the unbroken ore has been used to describe the liberation characteristics and the association between mineral phases. The linear grade distributions for selected particle size fractions were determined by means? of a particular implementation of King's Random Fracture Model that uses the exponential model for the distribution of linear intercepts through both dispersed (kaolinite) and continuous (gibbsite) phases. The corresponding volumetric grade distributions were then determined by means of a constrained optimization technique for the solution of the transformation equation. Batch flotation experiments were carried out to determine the kinetics for particles of different sizes and the results correlated with the liberation spectrum for each size class.

Jan 1, 1991

By M. U. Khan, A. D. S. Gillies

"Diesel exhaust is a major cause of large number of occupational diseases. Acute and continuous exposure to Diesel Particulate Matter (DPM) can cause numerous health issues including respiratory disease, reduced lung capacity, heart disease etc. The National Institute of Occupational Safety and Health (NIOSH) and the International Agency for Research on Cancer (IARC) consider diesel engine exhaust as carcinogenic. In large underground metal and nonmetal mining operations, regulatory compliance regarding miner’s exposure to airborne particles especially DPM is a big challenge. Complex mine networks add more difficulties in controlling DPM. MSHA relies on the NIOSH 5040 method for DPM compliance. The NIOSH 5040 method is a shift average based method which inherits some limitations. Due to these inherent limitations of the NIOSH 5040 method the concept of real-time DPM monitoring is promoted in the mining industry. Several real-time DPM monitors have been used by the researchers and efforts still continues to improve their measuring techniques and understanding. Real-time monitoring of DPM is vital to gain understanding of rapid changes in the mine atmosphere. The current study highlights the advancement in real-time DPM monitoring and mainly covers a review of several studies in which DPM concentrations were measured by utilizing real-time DPM monitors. INTRODUCTION Ventilation of underground mines is an important aspect of mining operations. Mining is a continuous activity and the ventilation networks in modern mines change with extended developments. Proper understanding of the ventilation network is a key design factor of an optimum mine ventilation plan. An important task of underground mine ventilation engineers is to provide clean air with sufficient quantity to the underground miners (Khan M. U. and Gillies A.D.S. 2015). The amount of fresh air supplied to the mine should be adequate to dilute the concentrations of contaminants present in the mine atmosphere. In the United States it is estimated that diesel powered equipment is used in thousands of mining operations (Stephenson D. J. et al. 2006). Use of diesel powered equipment is an attractive option in underground mines due to its several advantages over other available alternates. Diesel engines are rugged, dependable and fuel efficient (McKinnon 1999). It is common for diesel engines in heavy duty trucks to have a life of 1.6 million kilometers (McKinnon 1999). Looking at the developments in other energy alternatives, it can be assumed that the underground mining industry will maintain its reliance on diesel powered equipment (Anon 2001). DPM is an important source of mine air contamination in many non-gassy underground mines (Khan M. U. and Gillies A.D.S. 2015). Diesel exhaust is harmful for humans. Acute and continuous exposure to diesel exhaust concentrations can cause several health issues. Some of the health diseases caused by DPM exposure are respiratory diseases, reduced lung capacity, heart disease, and lung cancer (National Research Council. 1981, Mine Safety. 2005). In addition, NIOSH regards diesel exhaust as “potential carcinogen” (Centers for Disease Control 1988) and IARC has declared that “diesel engine exhaust is carcinogenic to humans” (IARC 2012). NIOSH has also declared that the reductions in DPM exposure would reduce cancer risks (Centers for Disease Control 1988)."

Jan 1, 2016

By Morton Handelman

The extraction of aluminum oxide_ from its ore is the initial step in the commerical production of metallic aluminum. This is most commonly done by the Bayer Process in which a caustic solution is used to dissolve hydrated alumina from the insoluable materials with which it is associate in bauxite. At the two-thousand ton per day Sherwin Alumina Plant of Reynolds Metals Company, the extraction residue from Caribbean ores is removed from the main pro¬cess stream as the underflow of a continuous clarifier-thickener operation. This sludge, prior to its ultimate r4jection from the process, is washed in a nine-step continuous countercurrent decantation system to recover physically-entrained mother liquor. Control of alumina production costs requires the optimum recovery of solubles from this residue which is generated at the same rate as the finished product. The equipment, operating techniques, controls and process variables which affect the efficiency of this soda recovery from Bayer Process red mud will be discussed.

Jan 1, 1959