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By E. R. Maize

This report is the second of a series on roof movement in coal mines. The first (R. I. 3355)4/ dealt with convergence of roof and floor and movement of the surface accompanying and following extraction in a mechanized mine in which retreat of rib lines was rapid. The studies reported herein were made in a mine in which all the coal is loaded by hand, and movement of the rib lines was much slower in consequence. In choosing a site for this work, it was decided that the mine selected should have natural conditions akin to those of the first study and entirely different methods of working. To this end a cooperative agreement was made with the Crucible Fuel Co. through W. J. Whitaker, secretary, for conducting the work in the company's Crucible mine, operating in the Pittsburgh bed in Greene County, Pa. This paper gives an account of the methods used in the investigation, excerpts from the data obtained, and such generalizations as can be made.

Jan 1, 1939

By Edwin E. Maust

In response to the ever- increasing demand for high temperature materials, the Bureau of Mines instituted a program for the study and development of superrefractories, One of the major tools obtained for use in this research was an image furnace of the double-paraboloidal mirror type. Although extensive theoretical analyses of solar furnace performance may be found in the literature, comparable detailed information on the double-paraboloidal-mirror image furnace has been nonexistent. This report presents an analysis based on an investigation undertaken to ascertain the limitations and characteristics of the furnace so that it can be used most effectively. The quantitative determination of the energy available at the image, the control of this energy by mans of a 60-inch iris diaphragm, and its variation with position and time relative to the heat source used have all been dealt with in detail. The quantitative results were obtained using a specially designed waterflow calorimeter and these measurements, in conjunction with the theoretical analysis, are used to present a fairly complete description of the furnace and its capabilities.

Jan 1, 1962

By John A. Johnson

The purpose of this report is to clarify the interpretation of some phases of previous progress reports5/ on the use or omission of stemming that have been brought to the attention of the authors by readers. As the stemming problem was approached from an entirely disinterested viewpoint and the data were presented impartially, results of investigations published in previous reports5/ were obtained under a definite set of conditions and procedure, and they may of may not be duplicated under different conditions and procedure in actual mining practice. Final conclusions regarding the use or omission of stemming in blasting have not been reached pending completion of all aspects of this investigation.

Jan 1, 1942

By Kenneth Eilerts

The development and operation of "combination wells"5/ have created new and unusual problems, many of which can he solved only if information is available concerning the properties of the fluids produced. Data as to the characteristics of the fluids at the relatively high pressures that exist in the reservoirs are especially important, and there is growing economic concern to know what part, if any, of the liquid recovered at the surface was liquid in the reservoir, As an extension of this problem, it is important to know, whether liquid will be formed in the reservoir as a result of isothermal retrograde condensation when the reservoir pressure is reduced. The pressure range of such condensation, if it occurs, is significant in the design of gas-recycling plants for maintaining reservoir pressures. In connection with the operation of such plants, it is particularly important to know how pressure and temperature will affect the yield of the liquid phase and the composition of the gas to be returned to the reservoir. It has not been possible to predict the behavior of these fluids that have high ratios off gas to liquid by comparing them with the behavior of low gas-liquid ratio fluids at identical pressures and temperatures. Such comparison fails because the proportions in which a component will be distributed between the phases of a system at any given temperature and pressure depend increasingly on the composition of the mixture as the critical temperature and. pressure of the system are approached. Because many combination wells are producing from reservoirs that have temperatures near the critical point, experimental date on the properties of the Fluids under reservoir conditions are particularly important at this time, To meet the immediate requirements of the industry for such experimental information, an equilibrium cell has been constructed at the Petroleum Experiment Station of the Bureau of Mines, Bartlesville, Okla. When adequate experimental date have been accumulated, it may be possible to make dependable estimates of the phase relations for high gas-liquid ratio fluids at the pressures anti temperatures characteristic of "combination-well? reservoirs.

Jan 1, 1940

By F. T. Cawood

?It is in the interest of stability and investor confidence that the healthy and necessary debate on such a (minerals) policy should soon find its way to consensus.? (President Nelson Mandela at the104th (1995), AGM of the South African Chamber of Mines) Inauguration of the new political dispensation in South Africa initiated a dynamic period in the historical development of its minerals policy. The process of substituting the current South African mineral policy framework with an acceptable ?post apartheid? system, started soon after the 1994 election of the African National Congress (ANC) government. The Green Paper on a Minerals and Mining Policy for South Africa released for public discussion in February 1998, calls for radical transformation in mineral rights ownership. A shift towards exclusive state ownership of mineral rights, away from the present dual system of private and state ownership, is the most significant proposal. The current holders of mineral rights, or their nominees, who lawfully enjoyed security of tenure under past and present mineral laws are opposed to this transformation because mineral rights were often acquired at considerable cost. The situation is compounded by poor public record-keeping and passive mineral rights administration over a very long period. This paper represents a summary of the historical developments leading to the current legislative environment and forms the basis for any discussion on which future sculpturing of South Africa?s policy regarding mineral rights can take place. One cannot plan for the future without considering the past!

Jan 1, 1998

By E. R. Maize

This report is t e second of s series on roof movement in coal mines. The first (R. I. 3355)4/ dealt with convergence of roof and floor and movement of the surface accompanying and following extraction in a mechanized mine in which retreat of rib lines was rapid. The studies reported herein were made in a mine in which all the coal is loaded by hand, and movement of the rib lines was much slower in consequence. In choosing a site for this work, it was decided that the mine selected should have natural conditions akin to those of the first study and entirely different methods of working. To this end a cooperative agreement was made with the Crucible Fuel Co. through W. J. Whitaker, secretary, for conducting the work in the company?s Crucible mine, operating in the Pittsburgh bed in Greene County, Pa, This paper gives an account of the methods used in the investigation, excerpts from the data obtained, and such generalizations as can be made.

Jan 1, 1939

By S Speed, N Corlis, A Goldstone, G N. Browne, M Fitzpatrick

In 2005, Solid Energy New Zealand Limited obtained non-notified consent for the disposal of 1Mt of coal ash at the Rotowaro minesite, forming part of a coal supply agreement with the Huntly Power Station. A non-notified resource consent was sought which necessitated that environmental effects be shown to be æless than minorÆ, and resulted from robust science and a pragmatic approach to design. As part of the assessment of environmental effects, there was a need to understand the effects of boron concentrations on aquatic organisms (ie algae, plankton, plants and invertebrates) in the receiving environment. Boron is a naturally occurring element that is found in the form of borates in the oceans, sedimentary rocks, coal, shale, and in some soils but Waikato coals and ashes have particularly high boron content. Boron is an essential micronutrient for higher plants with interspecies differences in the levels required for optimum growth. As aspects of the ANZECC (2000) derived boron limits are based on toxicity of aquatic algae and plants to boron it was important to assess these components in the environment. The effects on the receiving environment of the Awaroa Stream were assessed using predicted water chemistry and comparing actual boron concentrations in a comprehensive and multifaceted reference-condition approach of catchment ecological indicators. In addition a toxicological-based assessment of boron and a re-calculation of the ANZECC trigger levels were undertaken and applied to the ecological indicators. The reference-condition approach revealed that habitat and overall water quality attributes at and between sites was more influential in determining the aquatic biotic communities than boron concentrations alone. There was no evidence of any gradient of changes in ecological indicators with changing boron concentrations, nor evidence of any residual effect of high historic boron concentrations on the aquatic biota.

Jan 1, 2006

By John A. Johnson

The purpose of this report is to clarify the interpretation of some phases of previous progress reports5/ on the use or omission of stemming that have been brought to the attention of the authors by readers. As the stemming problem was approached from an entirely disinterested viewpoint and the data were presented impartially, results of investigations published in previous reports5/ were obtained under a definite set of conditions and procedure, and they may of may not be duplicated under different conditions and procedure in actual mining practice. Final conclusions regarding the use or omission of stemming in blasting have not been reached pending completion of all aspects of this investigation.

Jan 1, 1942

By V. F. Swanson

As part of the Bureau of Mines titanium resources examination program, samples of altered rock (saprolite) and unaltered rock from the Roseland anorthosite near Roseland, Nelson County, Va., were tested for amenability to beneficiation by flotation. A flotation technique was developed to produce bulk concentrates of ilmenite, rutile, sphene, and leucoxene. It was necessary to first float apatite using oleic acid as the collector, in an alkaline pulp with dextrine as a titanium mineral depressant. The titanium minerals could then be floated from the apatite tailing, using fluosilicic acid to depress the remaining apatite, morin to depress ferromagnesian minerals (when present), and oleic acid as the collector. A bulk titanium mineral concentrate, analyzing 66.0 percent Ti02 and 0.08 percent P205, was obtained from a sample of the unaltered rock which contained 5.45 percent TiO2 and 2.81 percent P205. Overall recovery in the concentrate was 47.1 percent of the total TiO2 in the ore. About 55 to 65 percent of the saprolite sample was clay and was removed by attrition scrubbing and decantation. The apatite prefloat procedure was applied to the saprolite sands; subsequent titanium mine: 1 flotation recovered 72.2 percent of the Ti02 in a bulk concentrate containing 65.1 percent TiO2 and 0.20 percent P205.

Jan 1, 1962

By P. P. Jenkins, T. G. Ball

Paper presented at the Drillex '90 conference held in London, 5 April 1990. Two drilling techniques are employed - guided longhole drilling and reverse circulation coring - for underground longhole exploration of the coal reserves and the fault structures that affect them. These are complementary to, or replacements for, surface boreholes, underground development drivages and seismic techniques. The developments of the drilling techniques and some case histories are presented in detail.

Jan 1, 1991

By C. Musingwini

The South African mining industry continues to be a major source of employment at a time when at least 25 per cent of the working age population is unemployed. At the same time the industry faces a skills shortage in many of the disciplines necessary for its future health. The University of the Witwatersrand, University of Pretoria, University of Johannesburg, and University of South Africa have historically produced mining graduates for the South African mining industry with any shortfall being met by the recruitment of overseas graduates. More recently, the global shortage of engineers and other mining industry professionals has seen a reversal of this trend and a very significant emigration of well-educated and highly skilled personnel. The traditional career path for mining graduates is in production and mine management. However, there is the parallel (and possibly more pressing) need for specialized skills in such fields as ventilation, rock engineering, mine planning, mineral resource evaluation, and mineral asset valuation. Chronic shortages in these essential areas continue to hamper the development of the industry and may well frustrate its ambitions to be safe, healthy, and profitable into the future. The permeability of skills across sectorial boundaries within the mining industry requires that skills shortages in the platinum sector are not looked at in isolation, but within the context of the entire industry. This paper reviews the efforts being made by the universities, at both undergraduate and postgraduate levels, to meet the needs of the South African mining industry in terms of the required numbers and the range of specialized skills.

Jan 1, 2013

By C. W. Owings

A few of the more progressive mining companies have taken precautions to safeguard employees or man-trips. Specially constructed men-cars -have been provided with special devices or mechanisms to stop the cars on slopes, if the hoisting cable should break. Cars have been equipped with safety chains to connect and hold them together if a coupling should break. Steel frames covered with heavy wire netting have been placed over cars to reduce injuries to the riders from roof fails on slopes. A safety cable passing from the front car to a point above the cable socket on the slope hoisting cable is used frequently as a precaution in case the socket loosens o the main cable breaks at the socket. Such devices are commendable, but the percentage of man-cars and man-trips protected is relatively small - entirely too small. Man-trips that travel level haulage roads are rarely protected safety devices, and haulage roads are seldom inspected by mine officials to determine the condition of roof and ribs.

Jan 1, 1935

By H. Zhu

Coal desulphurization by flotation is often difficult due to the surface oxidation of coal pyrite. Scanning electron microscope (SEM) and X-ray diffraction (XRD) were adopted to obtain detailed information about the surface oxidation of pyrite. Fresh pyrite surfaces were found to be hydrophilic, and to turn hydrophobic after initial oxidation, with oxidized products such as polysulphide FeSx and free sulphur. The oxidized products on the pyrite surface were reduced by an electrochemical method, returning the surfaces to a hydrophilic state and thus increasing the separating efficiency of coal from pyrite by flotation. Key words: surface oxidation, pyrite, SEM, XRD pattern, electrochemical modification.

Jan 1, 2002

By Albert E. Long

THIS GLOSSARY is published lay the Bureau of Mines as a contribution too the mining literature to fill a long-felt need for a compilation of the terms used by the diamond-drilling industry. The first step toward preparation of the glossary was taken in October 1955 when the Diamond Core Drill Manufacturers Association (DCDMA) proposed that the Bureau of Mines undertake the cons compilation and publication of a glossary of the terms used by the diamond-drilling industry. The work was authorized in July 1956, and a preliminary draft of the glossary was completed in may 1958. Copies of the draft were submitted for review to members of the DCDMA and appropriate personnel of the Bureau of Mines. The final draft, incorporating the many helpful suggestions of the reviewers representing both the diamond-drilling industry and the Bureau of Mines, was completed in March 1959.

Jan 1, 1960

By Will Foreman, Douglas D. McLearie, Edwin K. H. Tong, William H. Hansmire

Hong Kong’s Strategic Sewage Disposal Scheme (SSDS) Stage I involves the provision of a system of deep tunnels for transporting to a central treatment works wastewater collected from a number of catchments around Victoria Harbour. For the SSDS Stage I works, about 24 km of tunnels have been excavated in hard rock at depths ranging from about 80 to 150 m below Victoria Harbour and the surrounding heavily developed areas of Kowloon and Hong Kong. Five tunnel boring machines(TBMs) with diameters ranging from 3.2 m to 4.3 m were used to excavate the tunnels. Tunnel excavation has been completed and tunnel linings are in progress. Major tunnelling issues such as ground stabilisation and water control encountered in the project are summarised. An overview of one of the possible future tunnel systems that might be adopted in subsequent stages of SSDS is also presented.

Jan 1, 2001

CONTENTS:1. Introduct'iona. Previous Accountsb. Summary of Geologyc. Physiography2. Morgan Groupa. Lithologyb. Structurec. Faulting3. The Mineral Deposita. Descriptioni. Size and Shapeii. Compositioniii. Effects of Oxidationb. Relationship to Structurec. Genesis of Ored. Mount Morgan Orebodye. Sugarloaf Orebody4. Granitea. Mount Morgan Graniteb. Town Granite'c. Moonmera Granite5. Calliungal Beds6. Razorback Beds7. Acknowledgments8. References

Jan 1, 1952

By John A. Owsiany

The effect of longwall mining on streams and shallow aquifers has been the subject of numerous research studies for more than twenty years. As a result of these studies, it has become common to consider an overburden thickness of 400 feet as the lower limit at which longwall mining methods may be used with little or no effect on hydrologic systems. This paper presents the results of a study documenting the response of a large high order stream to shallow cover undermining by longwall methods in the northern Appalachian coalfield. The field site is located in a narrow stream valley where the overburden, composed primarily of limestone and sandstone units interbedded with shales and siltstones, ranges in thickness from 340 to 285 feet above the main bench of the Pittsburgh coal seam. Streamflow monitoring and monitor well measurements indicate that no significant loss zones or water table lowering resulted from undermining the stream or the adjacent valley bottom area. Additionally, hydrographs for shallow near-stream wells exhibit fluctuations related to natural seasonal variations, which are nearly identical to those observed in a non-undermined control well in the same watershed. Environmental factors affecting streamflow were monitored through the use of a control stream in an adjacent non-undermined watershed to differentiate between natural and mining induced changes in flow.

Jan 1, 2001

By J Hadijigeorgiou, R. W. Lawrence, R Pouling

The layered co-mingling method involves the disposal of waste rock with the addition, at predefined construction stages, of layers of dewatered mine tailings. The resulting waste structure displays bulk properties that are more favourable to acid rock drainage (ARD) control than the constituent materials alone. A laboratory test programme was conducted to examine the potential of this method. Columns containing different configurations of waste rock and tailings were percolation leached for 40 weeks and the leachates examined for various parameters. In the short term the chemical reactions that result from the introduction of dewatered tailings into rock waste can significantly improve the quality of the drainage. Columns with co-mingled material produced leachate with pH levels of 8, whereas leachate from the control column containing waste rock alone had a pH of 4. Larger-scale field tests are planned to determine the effect of the disposal method over the longer term

Apr 1, 1996

The Bureau of Mines has reviewed those portions of the "Tariff Schedules of the United States Annotated 1963" that are of interest to the minerals industry. This study shows to what extent rates of duty were altered (increased or decreased), and provides a bridge where possible from the old Schedule A classification sys tem to the new TSUS system of statistical reporting of import data. In general the new tariff has corrected previous classification defects and inconsistencies, but the rates of duties have not been materially changed.

Jan 1, 1965

By Graham Davey

"Low speed stirred milling has been employed for many years in the metalliferous and industrial minerals industries. High speed stirred milling is a relatively new method of grinding in the metalliferous process industries. However it has been it has been in wide spread use in the industrial mineral field for over 30 years for various minerals. Many existing metallurgical operations are looking to maximize economic return from existing deposits, requiring new thinking and technologies. By combining low speed and high-speed milling fine and ultrafine grinding efficiency and operating costs can be improved.The correct selection of different fine grinding technologies is covered, when each mill is applicable and when a combination of the VERTIMILL® Grinding Mill and SMD provides the best economic solution.INTRODUCTIONUltra-fine grinding of minerals has been in wide spread use in the industrial mineral field for over 30 years. Within the last 10 years the metalliferous industry has shown interest in the ability to produce ultrafine particles, as chemical, physio-chemical and physical separation processes have advanced to be able to treat ultrafine metalliferous particles. Also as the primary mineral deposits, around the world are depleted, new more difficult deposits must be mined. Existing operations are also looking to maximize economic return from existing deposits, requiring new thinking and technologies.The traditional approach for gold containing refractory material has been to liberate the locked gold by chemically destroying the pyrite through oxidation. Roasting, pressure oxidation, and bacterial oxidation all employ various degrees of temperature, pressure and catalysis to react the pyrite with oxygen to produce iron oxide and sulfur by-products. However all of these methods are economically impacted due to specific operational added requirements and emissions controls. Pressure and bacterial oxidation have very high capital and operating costs."

Jan 1, 2006