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By G. Vijaya Kumar, B. Srinivasa Rao, G. V. Krishna Rao

The paper outlines the ventilation practices prevailing in coal mines of Singareni Collieries Company (South India). The high annual average surface temperature and relatively steep geothermic gradient results in virgin strata temperatures in the region of 38- 42°C creating environmental problems in the working places. Expensive methods of air cooling can not be employed as the mines are small, and production and productivity do not justify the costs of artificial cooling of mine air. Controlled recirculation of mine air -- the unconventional technique being tried with success in some coal mines in U.K. has been analysed for improving the environmental conditions. The analysis shows that the method is safe, cost effective and can be applied with very little extra equipment.

Jan 1, 1991

By J. W. Wilson, Y. P. Wang, M. H. Erten

The use of water is still the most effective and economical means for dust control in underground coal mines today along with dilution by the ventilation current. Studies have shown that the dust capturing capacity of water is a result of a balance of many intermolecular forces. Surfactants are known to reduce such forces by affecting both the surface tension of the liquid and its interfacial tension against a solid. Surfactants can be added to the water sprays to facilitate the dust capturing capacity. A laboratory scale model has been developed in which surfactants were added to the spraying water and preliminary data indicates positive results.

Jan 1, 1991

By E. Watkins, V. Gangrade

Large-opening stone mines often rely on natural ventilation and a network of auxiliary fans to produce adequate ventilation conditions in the mine instead of main mine fans, which are commonly utilized in coal mines. Large air volumes in underground stone mines, poor ventilation practices, and low operating budgets for mine ventilation potentially increase mine workers’ risk for dust, silica, and diesel particulate matter (DPM) emissions exposure. To help improve mine ventilation practices, the optimal auxiliary fan location for maximum airflow production from a ventilated intersection was determined using a combination of field measurements and computational fluid dynamics (CFD) modeling. In this study, conducted by researchers at the National Institute for Occupational Safety and Health (NIOSH), airflow quantity and fan data were collected at a partner mine to be applied as CFD model input parameters and comparison data for model validation. A six-foot diameter auxiliary propeller fan was introduced into the validated CFD model at three locations at a mine entry intersection with established ventilation flow perpendicular to the fan direction. Placing the fan on the opposite side of the intersection from the target active face area produced the highest ventilation flow rates at the downstream locations tested and produced the lowest amount of air re-circulation. The findings show that optimizing the placement of an auxiliary fan may increase the net effective ventilation flow rate by 70,000 cfm and reduce recirculation by 26%, which maximizes the potential effectiveness of large-opening stone mine ventilation systems and decreases mine worker exposures to airborne contaminants.

Mar 2, 2022

By Ernest Koenigsberg

In 1961 Lerchs and Grossman presented a method, based on graph theory, to determine the optimum ultimate pit limits for an open-cast mine. At the same time they demonstrated a dynamic programming algorithm for the optimum pit limits for a two-dimensional open-cast mine. Since then many methods for determining optimum limits for three-dimensional mines have been programed, and even more have been reported in the literature. The methods include computer "simulation" of the manual methods used by engineers, the development of sets of conic sections and fitting to exclude overlap, integer linear programming (and its equivalent network flow model), and dynamic programming. Many of the methods do not guarantee optimal solutions but seem to satisfy the user. Other reported methods have never been applied, partly because they did not yield optimal solutions. We have developed a three-dimensional dynamic programming algorithm which requires a single pass through the data. Large problems can be solved on a small computer because only a small part of the data is required at any time. In this paper we will review the state of the art and to demonstrate the connection between linear programming (and network flow) models and the dynamic programming method.

Jan 1, 1982

By A. Peppas

Perlite is a naturally occurring siliceous rock, which can be expanded from four to twenty times its original volume when heated at a temperature close to its softening point. The expanded perlite is characterized by increased sound and thermal insulating properties. However, the conventionally expanded perlite products have high porosity and low mechanical properties that limit the range of their applications in the construction and chemical industry. The present work aims at the development of new closed porous microcellular material from perlite with enhanced mechanical and physical properties to be applied in new applications, like joint compounds, functional fillers for special paint types, special blasters and mortars, artificial marble. For the production of these new materials a vertical electrically heated furnace with six different heating zones and controlled gradient temperature profile was used. The effect of major process parameters, like temperature and air flow, on the quality of the produced materials was studied using Greek perlite from Milos Island. The quality of the new products was evaluated in terms of their bulk density, compression strength, water and oil absorption, surface area and pore volume. The experimental results show that the produced materials are characterised by improved mechanical and physical properties compared to the conventionally expanded perlite products.

Jan 1, 2006

By T. Hayes

Track-type tractors remain one of the most cost-efficient stripping tools available to coal miners. Whether they are "sweetening up" a dragline operation with pre-benching or serving as the primary stripping tool, dozers can play an important role in driving down mining costs. This paper reviews the application zone of track-type tractors. In addition, it provides tips on site set-up, equipping of tractors, and machine operation which the audience can take home and apply.

Jan 1, 1996

By James W. Cooksley

Through the early stages of metamorphism, when diffusion is the predominant mineral forming process. there is a tendency toward homogenization of rock units; but there is also zoning resulting from differing primary lithology and structure. Later stages of metamorphism, when infiltration occurs, tend to intensify zoning within the rock mass. The above concepts have been borne out in exploration of talc deposits and skarns. Initially, geologic mapping and soil sampling are directed to understanding mineralogy and petrology. Later, seismic methods are employed to further define lithology in the subsurface. Magnetometer surveys can also define some metamorphic units efficiently. Then, drilling must ensue to confirm lithology and determine extent of mineralization.

Jan 1, 1992

By J. Muir

This report focuses on minimum ore block sizes that are economically feasible to mine with the vertical crater retreat (VCR) method. In 1985, Homestake Mining Co. began a program to bring several small block VCR stopes on line. This report examines these experimental stopes, including design parameters, ground control, drill patterns, secondary blasting, and mucking. Cost and scheduling comparisons are made with mechanized cut-and-fill and open cut- and-fill methods.

Jan 1, 1987

By Ronald L. Wiegel

The United States produces approximately 40 mil- lion tons of phosphate rock per year. Most of this rock is converted to diammonium phosphate and used as a fertilizer component for the domestic and international agricultural market. Much of this phosphate rock production is concentrated in the southeastern United States, with about half coming from washing and screening operations and half from flotation separation from sand and clay. This paper summarizes current operating practice in the industry and touches on some of the emerging technologies required to solve the problems associated with a diminishing high- grade reserve and the need to implement dolomite/francolite separations on a commercial scale.

Jan 1, 1999

By David W. Lillie, Pier A. Abetti

This paper reports on a study of the impact of fast growing new technologies on the market for copper over the next 15 to 20 years. The greatest threat is clearly the inroads of fiber optics on the traditional market for copper in communication cable. Opportunity areas identified include heat pumps, solar power and heat, desalination, electric vehicles and others. The overall impact of new technologies on copper is expected to be modestly positive if adequately encouraged by effective R&D.

Jan 1, 1986

By Y. C. Kim

For the past quarter of century, much more effort and research have been expended in developing the "optimum" ultimate pit limit design algorithms and much less to solving the "optimum" open pit production sequencing. However, the potential economic benefit to an operating mine is far greater for the latter than the former. Unfortunately, the problem of "optimum" open-pit production sequencing has not been fully solved to date. This paper first reviews the past and currently used methodologies for developing this sequence. The staggered pit phase geometry problem of advanced stripping and operational constraints such as ore and waste tonnage requirements by period and necessary contiguity of mining faces are the main reasons why the "optimum" production sequencing problem has not been solved as yet. This paper also explains why any method which attempts to simplify the problem using ultimate pit limit design algorithm will fail to reach an "optimum" solution.

Jan 1, 1994

By J. Derwin King, Harrison R. Cooper

Applications of nuclear magnetic resonance (NMR) offer possibilities for on-line sensing of the concentrations of several elements in flowing sample streams. In addition to hydrogen, these elements, generally of low-order atomic number, include aluminum, phosphorus, fluorine, sodium, boron, and lithium contained in minerals having commercial importance. Many such elements have been difficult or impossible to successfully measure on-line using the more familiar X-ray fluorescence and neutron activation analysis techniques. The availability of practical on-stream analysis methods is essential to applying advanced controls to processes incorporating these elements. On-stream NMR instrumentation has been demonstrated in the past for several process applications including, as an example, coal flow and analysis; and the technology has recently been extended to the measurement of phosphorous BPL in Florida beneficiation plants. The technique involves simultaneous sensing of proton (hydrogen) and 31P intensities to provide data for continuous calculation of BPL in the phosphate through calibration to volume fractions of water and solids. Initial operating results are described using the PhospholyzerTM on-stream phosphorous analyzer designed for plant application.

Jan 1, 1990

By J. M. Baker

It seems appropriate here to open with a quotation from the great pre-Confucian philosopher Lao-tze: "The softest thing in the world dashes against and overcomes the hardest. There is nothing in the world softer or weaker than water, and yet for attacking things that are firm and strong there is nothing that can take precedence of it." I am happy to report that our system of mining has worked out, with minor modifications, as well or better than was predicted. This, in a period of rising labor and material costs, has been most gratifying. Gilsonite is a solid hydrocarbon which occurs in vertical fissures cutting the sandstone and shale beds of the Uintah formation in south¬eastern Utah. It is found in other parts of the world under similar occurrence but nowhere else is it now being mined commercially. The Gilsonite veins on entering the shale members of the Green¬river formation break into small veinlets separated by shale, These veinlets are not now economical to mine.

Jan 1, 1959

By T. A. Toney

A sampling program was conducted in 2008 to determine the run of mine characteristics of 5 coal seams. The sampling program included size analyses and float sink determinations. The samples were analyzed for ash and mercury concentrations for each size and gravity fraction. This paper will report on the sampling program, the analytical results, and the correlations determined in the data set investigated.

Jan 1, 2010

By R. Benemelis

The existence of resins in some coal deposits in various parts of the world has been known for many years. These resins vary considerably in chemical structure and properties. The resin that is found in Utah coal, however, is rather unique, and has properties particularly attractive for the manufacture of printing ink mastics and adhesives. This resin is a rather dark, very high melting point, low molecular weight hydrocarbon resin. Its typical properties are shown in Table I. Its largest use by far, has been in the printing ink industry. The history of Utah coal resin is interesting, but unfortunately one of disappointment and failure.

Jan 1, 1990

By W. C. Peters

Geologists take the role of mine geologist when they apply their science to the design and operation of a specific minerals project. In doing so, they use the entire spectrum of procedures in economic geology and engineering geology to deal with a specific system of orebodies and associated environment. The objectives are established by stages in the life cycle of a mining operation as it goes from a prospect to a development project and on to a mine. This paper summarizes the elements of a mining geologist's role, with examples highlighted from the preceding papers.

Jan 1, 1992

By Evangelos Spyridonos, Thomas Frommer, Wolfdietrich Skala, René Prissang

Operational grade modelling is a technique that uses production data to run daily updates of property models. It will enable mining engineers to use property predictions based on the most recently acquired data as support for quality control and decision making. The approach necessitates that the properties of the run- of-mine material can always be attributed to individual mining blocks or charges. The software employed must be highly reliable, because a system failure or the loss of data could seriously affect the mine's quality management. An operational grade modelling system has been developed for the Breitenau magnesite mine. It makes use of the Linear Octree Based Property Modelling system which was conceived and realised at the Free University of Berlin. This paper describes the system design and gives an account of the experiences during the first six months since system start-up.

Jan 1, 1996

By M. J. Rex, K. L. Wiley, D. S. Ramey

In situ leaching, initiated in 1986 at the San Manuel Mine, was economically developed in 1989. The primary reason for this lag time between startup and viable production was the time required for technical development. The technical development pursued comprised detailed design, development and implementation of in situ well construction methods, formulation of suitable well pattern arrays and the development of extensive hydrogeologic and geochemical knowledge of the mineral deposit. Since 1989, the in situ leaching program has become a viable and cost-effective method to extract copper from the supergene mineralized zone of the San Manuel deposit. The in situ leaching methods that are currently used have been progressively expanded and continually developed. They will become the cornerstone of copper production from the San Manuel oxide mineral deposit. This paper presents an overview of the supergene hydrogeology, current design techniques, drilling methods and well completion, pump determination and setting, solution management and future plans for the increased extraction of copper by in situ leaching methods at the San Manuel Mine.

Jan 1, 1995

By G. Markopoulos

Thracean Gold Mining is a Greek Company specialized in gold exploration and exploitation. It is focused on the development of the advanced Perama Hill gold project, which is currently waiting approval of the environmental terms of reference from the Ministry of Environment. We have designed a mine operation that is completely safe environmentally. The mine design exceeds all the standards environmental safety set by the European Union. We are currently negotiating lasting relationships with the communities which surround the mine by creating sustainable projects within the area that will provide sources of income to the region long after the mine is exhausted.

Jan 1, 2007

By C. C. Harvey

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

Jan 1, 1996