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By R. Venkataramani

Even though the mining industry in 1966 produced more ore than ever before, current extraction rates are only a fraction of what is expected in the later years of the twentieth century. Nearly 90% of all metals and-mineral products consumed last year was recovered by open-pit mining. This has placed great pressure on this segment of the industry which has, consequently, resulted in some spectacular developments. With increasing size of projects, the need for increased sophistication of engineering, planning, management and administration of modern mining installations has never become more apparent. The design of complete systems for the mine and plant that fit the mould of today's business and social environments is undergoing an evolutionary process. Traditional concepts in mine development and operations are being sidestepped in favor of new ideas and principles. As the overburden thickness increases, materials handling presents a major problem to mining companies, especially those concerned with the mass production of ore and waste from low-grade deposits. The profit margin here is likely to be significantly less as to take chances with capital investment. 1 Constant efforts are needed to improve upon productivity if the ore is to be economically mined.

Jan 1, 1970

By Z. Hladysz

It is common to nine a coal seam affected by previous extraction of a coal seam below. As a result of that severe problems may occur during the extraction process. This paper presents the analysis of undermining effects based on field observations. A simplified method for the evaluation of risk in undermining operations is presented and predictions of the degree of possible damages to the undermined coal seam is given.

Jan 1, 1985

By William J. Bronkala

One of the oldest tools used in mineral concentrating is the magnetic separator. Virtually every mineral handling system has need for some type of magnetic equipment in two types of basic usage. 1. Equipment protection through tramp iron removal. 2. Mineral concentration based on magnetic properties of the minerals contained in the ore.

Jan 1, 1969

By Chi-shing Wang

The U.S. Bureau of Mines has been developing the mechanical roof pulling technique as a method for evaluating the effectiveness and the comparative advantages and disadvantages of various roof bolting systems, based on the characteristic responses of bolted nine roofs to a prescribed external loading system. Preliminary experiments were conducted in the Bureau's Safety Research Coal Mine using a 12-foot and a 16-foot-span test rig. The experiments have proved the capability of the test rigs and suggested the viability of the test method. This paper summarizes the test concept and the experimental results.

Jan 1, 1974

By Richard E. McGee

The paper presents a description of the procedures that were used to generate a ventilation criterion based on measurements of ambient mine air exhaust pollutant gases and ventilation airflow quantities. Today's economics dictate that a ventilation requirement be based on actual operating conditions. This will assure optimum economics and a safe working environment at the same time. The paper presents a methodology by which a ventilation requirement is based on the average maximum expected concentrations of nitric oxide (NO), nitrogen dioxide (NO2), carbon monoxide (CO), and carbon dioxide (CO2) that equipment operators in one of our Southeast Missouri mines will be subjected to. A graph has been generated whereby the expected maximum levels of NO, NO2, CO and CO2 are plotted against the ventilation quantity of a mine stope.

Jan 1, 1982

By Adrian Brown

Floor heave can be a major problem in large open pit mines. Unrestrained floor heave can lead to flooding, equipment destruction, slope instability and subsidence. It is particularly troublesome in coal mines where the floor is frequently relatively flat, and is often underlain by major water Searing units. This paper examines methods of analysis used in computing floor stability, and sets out a simple rational method of evaluating the required level of water pressure control to maintain acceptable floor stability. The approach is illustrated by reference to the stability of the floor of the Morwell open cut lignite project in Southeast Australia, where this approach has been used successfully for over a decade.

Jan 1, 1982

By D. W. Frommer

In continuing its long range studies of methods of treating low-grade iron ores, the Bureau of Mines has developed a new selective flocculation, desliming, and flotation procedure that enables effective beneficiation of the finely disseminated ferruginous jaspers of the Marquette range, Mich. The process, developed on a bench scale and later confirmed in the 800-lb/hr pilot plant, comprises dispersion, selective flocculation, desliming to reject fine silica and clay, and flotation of silica from the remainder of minus 400-mesh pulps. Pilot plant flotation of two Marquette range ores, using the selective flocculation procedure on feeds containing 36 percent Fe, yielded iron recoveries of about 84 percent in concentrates containing 65 to 66 percent Fe and 4 to 5 percent silica. These results were metallurgically superior to those obtained when selective flocculation was not used. Also operating characteristics were better, and reagent costs were lower.

Jan 1, 1964

By S. C. Termes

This paper discusses recent Federal Bureau of Mines research on the selective flocculation of various minerals with insoluble crosslinked starch xanthate (ISX). ISX is insoluble, has a shelf life of over a year when kept cold, and has a higher molecular weight due to cross linking than the soluble noncrosslinked starch xanthate used in previous flocculation studies on nonsulfide minerals. ISX readily flocculates a number of sulfide mineral fines but not silicious gangue. Floc formation, floc size, and settling rate are strongly dependent on pH, with the pH dependence differing for each mineral. Bornite has been selectively flocculated from bornite-quartz mixtures, and the bornite-containing flocs were separated from the unflocculated quartz using decantation and washing procedures.

Jan 1, 1982

By Bruno A. Fichna

Longwall mining offers low cost potential for coal with high capital investment. As opposed to two shifts-per-day operation in most long- walls, Saarberg Mines in Germany increase utilization of capital by operating their longwalls around the clock. Differentiation between capital and operating costs, corrective maintenance versus preventive maintenance, improved roof conditions, and economical life of equipment was investigated. A surprisingly high degree of improvement was attained. Capital costs at Saarberg longwall coal mines have been reduced through a step-by-step research and trial program. This reduction was particularly influenced by the high performance pilot longwalls at the Ensdorf mine. The following presentation shows data and figures of those longwalls. End results were 40% reduction in capital costs, which could contribute favorably to investment decisions in the coal industry in a supply side economics environment.

Jan 1, 1982

By V. R. Manukonda

Selective flocculation of iron ores is extremely sensitive to the type and the amount of soluble salts in pulp solutions. Chemical precipitation of alkaline earth ions combined with ultrasonic treatment deactivates their adverse effects without using any environmentally ill-defined reagents. The manner in which ultrasonic treatment affects starch adsorption on hematite, dissolution of quartz, and selective flocculation process was investigated. Selective flocculation tests were conducted in the presence of up to 400 ppm calcium ion on a quartz-hematite mixture by precipitation as calcium carbonate, and the role that silicate ion generated by ultrasonic treatment plays in achieving the selectivity of separation is discussed.

Jan 1, 1987

By Tsutomu Yanagase

Non-ferrous smelting industry in Japan often had the severe problems about the over production of sulfuric acid. There has been such a closed relation between amount of sulfuric acid from non-ferrous smelting industry and the products of copper, zinc and lead metals that the production of one ton of copper accompanies three tons of H2S04. When the proper balance exists in both markets this situation certainly brings bigger profits. In Xining and Metallurgical Institute of Japan the research commitee concerned with the fixation process of sulfur in non-ferrous smelting industry was established in 1977 and continued the activity for four years untill 1981. This paper will introduce some of the activities involved in the report published by the committee.

Jan 1, 1982

By C. E. Jordan

The fundamental properties of the Bureau of Mines patented dielectric separator were studied to provide insight regarding its design and operating characteristics. Force equations for mineral particles were derived and evaluated experimentally. High dielectric mineral recovery was proportional to the calculated effective dielectric force volume that surrounded each drum electrode wire. Electrode spacing was the most sensitive design parameter, requiring less than 0.4-cm electrode spacing for a good separation. Operating characteristics and ore characteristics were investigated. With a dielectric constant difference as small as 2, good separations were made on a laboratory scale at energy consumption below 12 kw?h/mt.

Jan 1, 1985

By Douglas E. Hansen

A current trend in blasting of large volumes of rock is to use increasingly larger diameter shot holes. The use of large diameter holes meant; correspondingly large explosive charges will be loaded and detonated, and, if special efforts are not made, will result in more damage and vibration beyond the intended blast area. With the rising awareness of environmental factors, vibration control becomes increasingly important. Equally important is the preservation of intended lines and grades, and in some cases by blasting with care, slopes can be safely steepended. In the past, vibration control was established to prevent damage to man-made structures. The quarry or open pit itself can be regarded as a structure composed of rock. Far too little attention has been given to the effects of blasting on rock walls. The primary purpose of blasting is to break rock. If the integrity of the rock has been destroyed beyond intended lines and grades, the excavation will be more costly than originally anticipated. The increased cost will not only be from in¬creased excavation due to overbreak, but also increased maintenance due to blast induced wall instabilities

Jan 1, 1976

By W. K. Summers

During the past few years monitoring systems have been installed to measure the effects of environmental changes on the ground-water resource. The design of a monitoring system depends upon the designer's perception of how the environmental factors merge with his perception of the ground-water flow system. The validity and representativeness of measurements made during a monitoring program depend upon the validicy of the designer's perceptions and concepts. To optimize the design of a ground- water monitoring program the designer should make preliminary measurements to confirm his assumptions.

Jan 1, 1985

By Dennis N. Poffenroth

One concern of the Mine Safety and Health Administration is the structural integrity of steel wire ropes used on mine personnel hoists and elevators. Failure of such ropes has resulted in loss of life and property. Although thorough and regular visual examinations are performed, hoist ropes may still fail from undetected internal wear, corrosion, and broken wires. To complement visual examinations, nondestructive rope inspection techniques have been developed to determine deterioration and removal criteria. The techniques use electromagnetic and permanent-magnet test instruments designed by a Canadian firm. This paper describes the operating principles, field and laboratory testing of these nondestructive testing instruments, and discusses the feasibility of using this type of testing as a supplement to visual examination and destructive tests.

Jan 1, 1982

By Michael F. Werneke

While the use of synthetic polymers for solid/liquid separation is not raw technology (1)(its history goes back to the mid 1950's), its importance has increased dramatically over the past decade. This can be attributed to two major factors. The first of these was a change to mechanized mining (strip mining and continuous underground miners) which resulted in a lower quality (higher reject) preparation plant feed, as well as a higher percentage of smaller size particles in the feed. The second factor has been the greater restrictions imposed by governmental agencies on effluent discharge and solids impoundment, requiring pre-treatment of recirculating water before reuse and treatment of refuse before disposal. Today, synthetic polymers find utility in almost all applications requiring separation of solids from aqueous suspension, including "in-process" as well as waste treatment applications. In spite of the fact that there are over several hundred commercially different flocculants available in the marketplace (2), there are a limited number of chemically different materials available which are useful from a cost/performance standpoint. The potential reasons for using flocculants in a coal preparation plant are summarized in TABLE 1.

Jan 1, 1979

By Brij M. Moudgil

Separation of oil shale from waste material or into high grade and low grade fractions can have a major influence on the economics of the surface (ex-situ) retorting process. Different components of shale rock vary significantly in physical and surface chemical properties such as specific gravity, color, water wettability etc. Various techniques which utilize the difference in one or more of the above propartis have been proposed to preconcentrate the oil shale before retorting. A discussion of the techniques proposed such as gravity separation, sorting and froth flotation is presented.

Jan 1, 1982

By Alexander Pomerantsev

In recent years, bucketwheel excavators have found wide application in open pit surface mining not only because of their large production capacities, but also because they easily lend themselves to automation. Krupp, Orenstein & Koppel, Buckau-Wolf, Mechanical Excavator, Lauchhammer, Manufacturers in Eastern Europe designed and installed many models of bucketwheel excavators that can excavate any type of materials, could be used in any climate conditions and for any type of technological schemes in open pit surface mining, (Photo I, II and III)

Jan 1, 1979

By Robert L. Grayson

In small coal mining operations, little is done in controlling supply and material inventories and optimizing total inventory costs. Material Requirements Planning (MRP) is an efficient material control system which time-phases net material requirements based upon production plans, bills of material data, and inventory status records. Inventory levels and total inventory costs are optimized using a lot sizing technique in placing time-phased purchase orders. The MRP system has been applied in large manufacturing firms utilizing mainframe computers, but it can be adapted to micro-computers for inventory control. This paper presents an application designed to assist the coal mine manager in optimizing inventory costs.

Jan 1, 1985

By Ellis J. Brien, O&apos

This afternoon I would like to talk to you about coal, its defi- nition, its constituents, its associated minerals and present and future coal preparation techniques. This discussion will be an attempt at presenting sufficient coal preparation and associated fundamentals to enable you to understand "deep cleaning", a more advanced beneficiation process which will be commercially practiced in the near future.

Jan 1, 1976