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By Fred Perea

The practical example of the effectiveness and necessity of establishing and maintaining close communications between the design engineering section and operating section of a large plant concerned with the building of an underground crusher will be presented.

Jan 1, 1969

By John S. Cummings

Although there are many geologic situations which might be discussed at a session such as this, as I considered the problem, it became apparent to me that I should discuss a situation which has been of concern to me, and should be of concern to the geologic community. As a result, the questions which I will pose, and the criticisms, have not been arrived at quickly or easily, but have accumulated through time, to the point where I feel discussion is necessary. Very briefly let me say that my criticism of geologic mapping, of conclusions reached, and objectives or lack of such, results from my association with many areas where such studies have been completed, and resultingly my inability to comprehend the system of evidence or logic which supports extensive age-formational designations. The heart of the problem is that many conclusions resulting in geologic designations are based on weak or non-existent evidence, and such should be catagorized as hypotheses. Although the geologic community as a group does not approve or disapprove of such designations, it is evident that many or most of such designations attain a "status", and arc accepted as more or less valid statements. As will be shown, the amount of specific lithologic data provided in some quadrangle mapping projects is exceedingly slim. However, of concern herein is that the type of information presented at any stage is sufficient to warrant conclusions drawn. To see the magnitude of the problem, it is probably necessary to review some basic fundamentals upon which our geologic systems are established. The United States Geological Survey has defined a "formation" as the broad unit of geologic mapping consisting of a large and persistent stratum of one kind of rock. Obviously such a designation allows that a formation could be considered "time variant" in a horizontal as well as in a vertical context. However, other definitions enable a formation to mean units

Jan 1, 1972

By Alden B. Carpenter

Oil-field brines have been collected and analyzed from Jurassic and Cretaceous rocks in the Mississippi Salt Dome Basin, from Jurassic and Lower Cretaceous rocks, southwestern Arkansas, and from Ordovician and Silurian rocks, southern Michigan. All of these brines are genetically related to evaporites and appear to be brines expelled from halite-bearing rocks, presumably during compaction. The brines in rocks closest to the halite-bearing rocks are uniformly low in lead and zinc suggesting that the metals in metal-rich brines are not acquired within evaporite sequences. The metals in metal- rich brines in Mississippi and in Russia appear to be derived from red beds and may have been originally associated with ferric iron oxyhydroxides. Reduction of these compounds by migrating hydrocarbons appears to release lead and zinc to the associated brines accompanied by the fomation of authigenic ankerite.

Jan 1, 1979

By M. Prasad, A. K. Majumder, T. C. Rao

The depletion of high-grade phosphate ores is bringing about a search for a suitable, economically viable technique that con process the abundant low-grade phosphate reserves. About 75% to 80% of the world's low-grade phosphate reserves are associated with carbonate gangue that is not amenable to treatment by the simple techniques of physical separation. The processing of sedimentary dolomitic/calcareousphosphate ore has numerous problems, including similar surface properties of the carbonate and phosphate. Two-stage reverse anionic flotation of carbonates (dolomite/calcite) has appeared to be a promising separation technique ,for the removal of carbonates from sedimentary rock phosphate. In reverse fatty-acid anionic flotation, the depression of phosphate mineral with orthophosphoric acid produces satisfactory results for calcareous as well as dolomitic phosphate ores from several locations of sedimentary origin.

Jan 1, 2000

By T. L. Heisler

The Cigar Lake project, located in northern Saskatchewan (Figure 1), is one of the world?s largest high grade uranium deposits, with reserves of 150 million kilograms of uranium in a deposit averaging 430 metres below the surface. The Cigar Lake project is being developed by Cigar Lake Mining Corporation (CLMC) which is owned by Cameco Corporation (48.75%), Cogema Canada (36.375%). Idemitsu Uranium Exploration Canada Ltd. (12.875%) and Korea Electric Power (2%). Mining the Cigar Lake orebody is presenting a very real challenge due to the high grade and the ground conditions in and around the orebody. Presently, an underground test of various mining methods is underway.

Jan 1, 1992

By T. R. Ellis

The vast majority of valuations produced for mineral properties using the net present value method provide an estimate of investment value or use value. Such an estimate can be a long way from the price that the property would actually sell for if placed on the market. Indicators from the market need to be used to validate or modify the net present value calculation if market value is being appraised. The comparable sales and replacement cost methods used in the appraisal of urban buildings generally fail when used in the appraisal of mineral properties. Other methods of sales analysis are introduced. Guidelines for what a minerals appraisal report should contain are presented.

Jan 1, 2002

By Daniel H. McClain

A unique partnership between the Colorado Mine Safety and Training Program (CMSTP), the Colorado Rock Products Association (CRPA) and the Higher Education and Advanced Technology (HEAT)Center resulted in a video CD-ROM training program for new miners entering the aggregate industry. Cooperation from everyone involved, including the U.S. Mine Safety and Health Administration (MSHA),made this the product against which other training materials in the mining industry will be measured in the 21stcentury. This product’s versatility and wide application make it a tool that is as critical to a mine’s success as any earthmoving machine. The state and federal grant money involved allows this product to be affordable to small operators and independent contractors. The quality of this two CD-ROM set rivals any commercially made CD-ROM training.

Jan 1, 2003

By A. R. Przybylek

A fluid bed dryer has been designed for a nonconventional application to upgrade the value of fine anthracite culm and silt recovered from culm banks and anthracite tailings pond beds. This material can be seen as large spoil piles scattered throughout the anthracite coal regions of Eastern Pennsylvania. Engineering of the system commenced in December of 1986 and at this writing start-up is scheduled for late October or early November of 1987. This paper will focus on generalities concerned With system design and operation, and qualify the differences from conventional fluid bed coal drying systems.

Jan 1, 1988

By S. C. Tadolini

Roof support systems have evolved from standing posts and timbers to a generation termed ?big nails? where steel bars are inserted into boreholes and anchored with expansion shells and/or resin cartridges. These systems have been effective but are limited to mining height. Additionally, the properties of steel do not resists shear forces or have the flexibility being required in difficult ground conditions. The next generation of roof support systems is coupling the best parts of the ?big nail? and resin grouted cable bolt systems. This paper will present the advanced technical solutions of the next generation of cable systems that includes an indented high-capacity PC-strand used with a variety of fixtures. Case histories of support applications will be presented.

Jan 1, 2012

By Robert G. Pinkerton

Boyles Bros. Drilling Co. and Gibbons and Reed Company, both of Salt Lake City, Utah, have successfully combined into two joint ventures on the San Juan-Chama project of the U. S. Bureau of Reclamation. The Azotea Tunnel is 12.7 miles in length; the inlet portal is on the Navajo River in Archileta County, Colorado, and the outlet portal is in New Mexico, about 10 miles south of the state border. The Oso Tunnel lies immediately to the north of the Azotea Tunnel and discharges water directly into it. We are presently driving both tunnels with mechanical boring machines from their portals at the Navajo River. Both tunnels are circular, fully concrete lined. The Azotea Tunnel has a finished diameter of 10 ft. 11 inches while the Oso Tunnel is 8 ft 7 inches in diameter. Both tunnels are supported with circular, structural steel rings as required by ground conditions. In good ground rock bolts and steel roof plates are used.

Jan 1, 1967

By Malcolm T. Wane

The subject matter of this paper, "Applied Rock Mechanics?," has its genesis in a recent field trip taken by the author. A more or less standard question asked at the mines visited was "How are you using the principles of Rock Mechanics to assist you in maintaining an efficient, safe, and competitive mining operation?" The question was couched in a number of different forms, but the intent was to determine whether or not a general theory based on reason and the scientific method was applied or whether the alternatives of tradition, intuition, ?common sense', revelation, ?shotgun methods' or authoritarianism were invoked. Perhaps two responses to this query will be illustrative of the general nature of the replies. At operation XYZ an extension to the known ore body has been found. The extension is of large enough size and grade that a mining scheme using load-haul-damp techniques is envisaged. Since this represents a departure from the present mining scheme, questions have arisen regarding pillar sizes, room and entry sizes and possible support requirements. A task force has been set up to expeditiously plan for these things and write the necessary specifications and requirements. The fundamental question was posed to members of this group.

Jan 1, 1971

By M. S. Klima, A. P. Pinkerton

Solid-bowl (decanter) centrifuges are used extensively to dewater slurries in a wide range of industries. However, the application of decanters as classification devices is not as common. In this study, the performance of a continuous, pilot-scale, solid-bowl centrifuge was evaluated when classifying an ultrafine coal slurry containing nearly 60% material less than 10 µm. The test conditions included centrifuge howl and scroll speeds, volumetric feed rate, solids concentration and pond depth. Centrifuge performance was evaluated using size selectivity curves and the corresponding performance parameters, along with product yields and solids concentrations.

Jan 1, 2002

By G. W. Poling

Chemical and physical properties of thiol collectors are reexamined to compare the prospects of heavy metal-thiolate or disulphide surface reaction products acting as actual collector species. Recent evidences for the existence and importance of each of these types of adsorbed species on sulphide minerals are also discussed. A conclusion is reached that partial coverage by chemisorbed heavy metal thiolate is often sufficient to confer practical levels of hydrophobicity and floatability. Only on a few highly conducting and "noble" sulphides does adsorbed disulphide-type collector oxidation product appear to be significant.

Jan 1, 1976

By John D. Price

In the constant search for ways and means of improving the quality of coke and thus making its use at the blast-fornace more satisfactory and economical, it has become increasingly evident that the present laboratory tests do not show the full picture of a coke's value as a blast-furnace fuel. This fact was recognized by Dr. A. C. Pieldner thirty-five years ago: (Ref. 1) here is perhaps no phase of fuel technicology which has aroused more discussion or regarding which there is more difference of opinion than the properties of coke which make it most suitable for blast-furnaces and other uses." Dr. Fieldner followed this assertion with a statement to the effect that men who write on this subject today (1923) have, because of conflicting experimental evidence brought forth in recent years, far less positive opinions on the matter than did writers of some years past. One is led to wonder if these statements are not just as true now as they were when first made.

Jan 1, 1959

By Raj K. Singhal

This paper is a report on a task force study dealing with many facets of computerization. The primary mandate of the task force was to examine the software and hardware currently available for application relating to reserve estimation, mine planning, economic evaluation, equipment selection, production scheduling and composite mine simulation and to evaluate how adequately the software fulfills the user needs in surface mining of oil sands and coal. To meet its objectives the task force consulted extensively with the users, developers and suppliers of hardware and software. The paper outlines the approach taken by the task force to fulfill its mandate, summarizes its findings and presents some pointers which might be useful to others considering this type of evaluation.

Jan 1, 1986

By Harrison R. Cooper

Composition data is needed as input for executing process control and management of particulate separation for flotation control. While requirements for composition data can be satisfied in many cases by manual sampling and analysis, automatic sampling and assay systems are now viewed as justified for all but the simplest or smallest processes. On-stream X-ray fluorescence analysis (XRFA) has satisfied requirements for the main portion of metalliferous sulfide ore flotation processes as XRFA technology evolved in reliability and sophistication from its beginnings in the late 1950's. In recent years, advanced on-stream analysis technologies have reached levels of development suitable for use in process control to increase efficiencies of important processes in mining and minerals industries such as coal fines flotation and industrial minerals beneficiation (particularly phosphate beneficiation) where XRFA methods have been inapplicable. Recent technical developments pertinent to use of advanced technologies as well as improvements to established on-stream composition analysis methods are discussed.

Jan 1, 1989

By Bobby P. Faulkner

Allis-Chalmers has combined a new heat transfer device, called the ROLLER GRATE, with a unique processing scheme, resulting in the ROLLER GRATE Oil Shale Processing System of Allis-Chalmers. In order to test both the process and the equipment, a batch Process Development Unit (PDU) ROLLER GRATE retort was designed and built. This unit vas designed with the flexibility to process shale over a wide range of test conditions in order to demonstrate the attributes of the oil-shale processing system. Instrumentation on the PDU and extensive sampling of the effluent streams permitted the PDU test data to be used in the design and scale-up of the process. Over 30 tests have been conducted with Colorado shale, and over 25 tests have been run with an Indiana shale. In addition, rests have been run with California and Utah tar sands.

Jan 1, 1983

By F. Wolf, R. Ellmies

"Fluorspar is one of the most important industrial minerals. It has a wide range of applications, for example it is used in the steel and aluminum industry, and is also the raw material to produce hydrofluoric acid, Teflon or Gore-Tex. There are only a few major fluorspar mines worldwide, with China being the most important fluorspar producer (U.S. Geological Survey National Minerals Information Center, 2017). At Okorusu, Namibia, fluorspar has been mined with conventional open pit mining methods from 1955 until 2014 from a large scale metasomatic fluorspar deposit with seven identified orebodies. There are about 7 million tons of measured resources left with an average grade of 27.5 % CaF2. This paper is based at an MSc thesis at Technical University Freiberg and describes the design of an underground mine for the A and D orebodies with an annual production rate of 100,000 t acid-grade fluorspar product. By comparing different mining methods and adapting variants of access to the underground orebodies the paper will emphasize on the selection of a suitable mining technology, with a special focus on the economic considerations to decide about the most profitable operation. INTRODUCTION Mining holds an important part in the economy of Namibia. In 2016 11.1 % of the GDP was made through mining activities with 22 active mines (The Chamber of Mines of Namibia, 2016). Only one of them consists an underground mining operation. The global annual production of fluorspar is approximately 6 to 7 million t (U.S. Geological Survey National Minerals Information Center, 2017). Okorusu produced on average about 50.000 t annually in recent years (U.S. Geological Survey National Minerals In-formation Center, 2015). Okorusu Mine is Namibia’s only fluorspar mine. Fluorspar was mined in an open pit mine with four individual pits (A-D) since 1980. In 2014 the mine closed due to the increased stripping ratio and beneficiation problems. The mine assets were bought by Gecko Namibia. Currently Gecko uses parts of the processing plant for beneficiation of graphite from a neighboring mine. Figure 1 shows a panoramic view with the four pits and the mine village. The intent is to develop a concept for the further underground development of the mine. There are still about 7 million t of measured resources left in the deposit, with an average grade of 27.5 % CaF2. This study focusses on the underground mine design. The above-ground plant and facilities are considered as remaining unchanged."

Jan 1, 2018

By R. Markovic

The objective of this research study was the investigation of heavy metal removal from wastewaters of the "SARAKA" stream by using low-cost materials. These wastewaters flow into Krivelj River and through the network of existing rivers into regional water reservoirs. Sawdust, cardboard and fly ash were used as reactive materials in laboratory studies. Sawdust was obtained from oak and fir-wood while fly ash from heating station Bor, bitter-oak and oak. Experiments were carried out using real Saraka stream wastewaters and the degree of removal for iron, copper, manganese and zinc was investigated. The content of these heavy metals in Saraka stream wastewaters was under the limit of III and IV class of water (Law on Water - Official Register of the Republic of Serbia). Parameters such as flow rate of water, pH and effluent volume, contact time between water and reactive material, etc, were monitored during the experiments. All used materials give satisfactory results for iron and other heavy metals removal; the highest degree of removal was obtained by using fly ash.

Jan 1, 2006

By H. W. Seany

Over the years since the initial experiments with underground concreting were made in 1956, attesting to cope with the ground weight and pressure encountered in the development of a large-scale underground block caving system, the use of monolithic concrete linings has grown to include most of the primary development in the, mining area. Although the development cost of concrete linings is higher than either timber or steel-supported openings, the repair and maintenance costs are substantially lower, making concrete the most economical means of ground support. Other advantages are also apparent, in that concrete provides superior fireproofing, better ventilation, and a safer, cleaner working place.

Jan 1, 1965