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By K B. Quast, A Schuurmans

Laboratory batch rod and ball milling tests were conducted on samples of Heavy Medium Separator (HMS) sinks from Renison Limited. The effects of mill rotation speed, rod volume and ball size on the resulting product size distribution were investigated. Between 48 and 69 per cent of critical speed, the product sizing distribution curves remained very similar, with a finer grind resulting from increasing the speed of rotation at constant grind time. Increasing the rod loading from ten to 53 per cent by volume caused the product size to become finer and more closely sized with a transition occurring at approximately 29 per cent. This was interpreted as a change of dominant grinding mechanism from abrasion to impact. No preferential grinding of the cassiterite was observed. The effect of increasing ball size at constant charge weight was to preferentially grind the coarser particles and generate more intermediate sized particles, whereas the product from a mixed ball charge gave a distribution similar to that obtained when a charge containing only smaller balls was used.

Jan 1, 1998

Listing on Australian Stock Exchange Limited ('ASX') is a means by which a company can prosper and grow by gaining access to a large capital market. This currently stands at over $300 billion for domestic securities listed on ASX. A company seeking listing will benefit from a higher profile and a greater spread of shareholders. These result from, among other things, improved communications with the investment community. ASX recognises that a decision to list is an important step for a company. Owing to the diverse nature and size of the companies that consider listing and the various steps involved, it is recommended that guidance of professional advisers is sought as early as possible in the listing process. A company seeking listing on ASX must meet the prerequisites for admission to the Official List which, along with the continuing obligations that must be complied with following admission, are contained in the Listing Rules of ASX. Listing on ASX requires a company to ensure that, among other things, the market is fully informed at all times so that investors can make informed investment decisions.

Jan 1, 1996

By M. C. Malamphy

A general description of the activities and results of bauxite investigation by the Bureau of Mines at its bauxite project in Saline and Pulaski Counties, Ark., has been given in Report of Investigations 4251. The factual data obtained during the project are reported in a series of Reports of Investigation beginning with No. 4251, of which this is the fourteenth. The data are accompanied by maps showing the location of holes drilled and the deposits developed. Each area upon which work was done is reported by half townships. Each bauxite deposit investigated was assigned & name and a number for ready reference and identification, and its location and name are shown on the appropriate half-township map. The description of each half township is followed by a description of each deposit developed in that half township. The 14 half-township maps and 77 detail maps of the bauxite deposits in this series of reports give the locations and numbers of all the holes drilled except the deep holes drilled to test geophysical anomalies. The locations of those holes are shown on figure 13 in volume 1. The descriptions of the deposits developed are followed by complete detailed logs of the drill holes. Many of the widely spaced exploratory holes did not discover bauxite of minable thickness and grade. The pertinent information obtained from the widely spaced exploratory drill holes has been summarized and tabulated, and a table for each half township is given with the discussion covering that area.

Jan 1, 1948

By Robert Torbin

The objectives of the Continuous Shaft Lining (CSL) System are to reduce the costs, safety hazards, and time currently required in lining mine shafts with concrete. The CSL will line machine bored shafts downward from the shaft collar on a continuous basis using an inverted, pressurized slipforming technique. The technique for slip-forming downwards has been demonstrated and refined under this program. The approach taken involved laboratory scale testing of key features of the CSL concept. These feature tests included concrete distribution, concrete sealing, concrete slipforming and development of a reliable concrete mix. Based on these results, a full scale above-ground test facility and CSL were designed and fabricated. The objectives of these tests were to demonstrate the viability of the basic concept; to establish operating limits; and to provide input data and information for the design of a second generation shaft lining system. The results of the program have led to a CSL design and operational philosophy which will need to be tested in an underground environment before industry will accept the technology. However, the next generation CSL promises to meet all the original program technical objectives.

Jan 1, 1983

By Guy Chevalier

The QCM Mount-Wright mine and concentrator complex produces about 14 M tonnes of iron concentrate annually. Approximately 9.5 M tonnes of this concentrate are used to produce iron ore pellets at four different silica grades: Three for blast furnace operations and one for direct reduction furnaces. The paper presents the scientific approach that led to the realization of two projects where the acquisition of new process equipment led to an improved pellet plant iron recovery, a better flexibility and to lower operating costs as well as to the production of fine iron ore concentrate from the Port-Cartier tailings pond. Typical 4.8 % SiO2 concentrate is processed to achieve required pellet silica content. This is obtained with the aid of hindered settlers or hydraulic classifiers, screens, whims and, lately, spirals. The increasing demand for low silica iron ore products resulted in a greater need for upgrading. The Pellet Plant upgrading capacity being limited, more and more iron units were lost. Base on test works results and economic evaluations, QCM engineers figured out a way to increase efficiently their upgrading plant capacity and go back in the pond gather what has been lost in recent years of operation.

May 1, 2007

By Frederick C. Trutt

This report is intended as a reference for personnel interested in the computer anlaysis of coal-mine-electrical-power systems under either normal operating conditions or fault situations. The procedures developed for this purpose are described and implementation considerations are discussed with respect to the mine-power system. Considerations for choosing a solution technique and a number of examples are included. Procedures described include the Newton-Raphson iterative technique for the analysis of normal operation as well as a non-iterative Z-bus technique for analysis of unbalanced or balanced faults. During program development, strict attention has been given to the inclusion of core and/or time saving techniques such that these algorithms may be implemented on small as well as large computers. Program languages include FORTRAN IV for batch processing applications and APL or BASIC for interactive applications.

Jan 1, 1981

By J. M. Wempen

Booster fans in underground coal mines are often located using the concept of a neutral point. Normally, intake airways are maintained at higher absolute pressure than return airways, so air leaks from intake to return. By adding a significant pressure force to a region of a ventilation system, booster fans installed in a return airway can increase the pressure in the return so that air leaks from return to intake. This is commonly referred to as recirculation. The neutral point occurs at the location in the system where the pressure difference between the intake and the return airway(s) is zero and at this point there is no leakage or recirculation. Ideally, placing a booster fan near the neutral point minimizes leakage and recirculation; however, in practice the position of the neutral point is not static and it changes as the ventilation system parameters change. This paper presents a study of how changes in the system parameters affect the location of the neutral point in a model coal mine ventilation system. First the effects of booster fan pressure and location on the neutral point are evaluated. Next the effect of increasing mine distance, and therefore mine resistance, on the location of the neutral point and the magnitude of recirculation is evaluated.

Jan 1, 2012

By E. A. Metz

Work related pulmonary diseases are in the top TEN causes of occupational disability and death in the United States. Likewise, it also ranks high inmost of the other industrial countries. It is difficult to know the true occurrence of occupational lung disease because of poor documentation. This is especially true when one examines workers’ compensation claims. Most frequently, silica and asbestos are paramount in our discussion of work related pulmonary disease. Little consideration is given to other “dust-related” diseases, irritant reactions, reactive airway responses, and hypersensitivity reactions. The major classification of occupational lung diseases will be discussed. This includes both acute and chronic disease that arises in the work place, especially, the mining industry. It’s more important to make an accurate evaluation and diagnosis for the prevention of disease among other workers.

Jan 1, 2000

By Herbert Cremer

The United States,-the largest nickel consumer in the world, produces virtually no nickel from domestic ores. Dependence upon outside nickel - sources and increasing strategic, importance of nickel focused the attention of the United States on deposits within its boundries. The most likely domestic sources of nickel are low-grade oxide and silicate deposits, such as the Cle Clum deposit, Kittitas County, Wash., and the Riddle deposit, Douglas County, Oreg. The Federal Bureau of Mines, Northwest Electrodevelopment Laboratory, Albany, Oreg. has been investigating electric smelting of low-grade oxide and silicate nickel ores. These smelting studies have been on selective reduction to produce low-carbon ferronickel. Selective reduction is based upon the relative reducibility of: nickel, iron, and chromium, in the order named, when the charge contains insufficient carbon or other reductants to reduce the entire quantity of these metals present in the ore.

Jan 1, 1954

By E. Don Dilling, Wm. F. Hergert, J. W. Pennington, C. E. Wood, M. J. Slendlove, H. A. Doerner

"INTRODUCTION The Bureau of Mines began a study of various methods for producing magnesium metal from magnesite ores in 1936 at Pullman, Wash., with the cooperation of Washington State College. This work included a study of the basic principles involved in the reduction of magnesium oxide by carbon, which soon led to the development of a continuous process. In May 1939, a small pilot plant was operated, which included a small single-phase arc furnace with a hydraulic feed mechanism and an oil-spray device for shock cooling the metal vapor. 5/Subsequently, the Ford Motor. Co., Dearborn, Michigan, began a study of this process on a larger scale. A pilot plant with a nominal capacity of 10 pounds of magnesium metal per hour was constructed and operated intermittently. A larger unit with a nominal capacity of 100 pounds of magnesium per hour was partly constructed when war activities prevented experimental work.In the meantime, the process was greatly improved through continued investigation by the Bureau of Mines at Pullman, and these improvements were successfully tested by continuous operation in a small pilot plant having a normal capacity of 4 pounds an hour."

Aug 1, 1945

These proceedings consist of an introduction, nine descriptive papers, and a summary. The first paper is an overview of the respirable dust research program, the second paper describes the Mining Enforcement and Safety Administration's proposed changes in the respirable dust enforcement program, and the third paper describes respirable dust measurement. The remaining papers, by Bureau and contractor personnel, describes methods of reducing the amount of respirable dust to which coal miners are exposed. Of the six methods of reducing exposure to respirable dust described, two are methods of preventing or reducing the amount of respirable dust raised during mining operations, two are methods of collecting or removing dust after it has been released into the mine atmosphere, 2nd two describe methods that are combinations of prevention and collecting .

Jan 1, 1977

By Lloyd Williams

1. The investigation shows that the Coal Creek has been the most productive, bed in Campbell County and contains the largest recoverable reserves of coal. The Pewee, Red Ash, and Jullico have been relatively productive beds and contain appreciable recoverable reserves of coal. The Blue Gem also has been productive in the past, but available information indicates that most of the remaining coal is Less than 28 inches thick. The Big Mary has relatively large reserves over 28 inches thick, but the coal is high in ash and sulfur. Thick partings in the Windrock bed have discouraged mining in that bed. The Poplar Creek and Rex beds generally are below drainage, and large areas have been excluded from the reserve estimate, Reserves in the Walnut Mountain bed will be difficult to mine due to the irregu¬lar thickness and lack of continuity of the bed. Estimated coal reserves are- small in the remaining five beds. 2. Known measured and indicated reserves of coal, based on a minimum bed thickness of 14 inches and on 1,800 short tons per acre-Foot of coal in place, are estimated to be 398 million tons as of January 1, 1953, o? this total, 267 million tons is in beds 28 inches and more thick. Areas in each bed were omitted from the estimate because available data relative to the bed characteristics are too meager to make an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, these should be added to the total estimated reserves.

Jan 1, 1956

By F. A. Patty

[Health and safety hazards from contamination of the atmosphere in places frequented by persons depend to a considerable extent on whether the contaminating agent possesses sense-perceptive properties which will give warning of its presence before it '.an create harmful conditions. If a distinct and easily recognized warning is given in advance of harmful conditions, hazards ace mitigated, but if warning properties are inadequate or absent, the hazards are augmented. When evaluating the hazard presented by a potentially harmful substance used under conditions of possible escape into the air of places frequented by persons, it is therefore necessary to consider the warning properties of the substance along with ether pertinent information such as toxicity, inflammability, physical properties, and mode of use. If the contaminating agent inherently lacks warning; properties it may be possible to impart them by adding to the hazardous substance a small quantity of a relatively harmless substance which has a high warning intensity.]

Jan 1, 1929

By Wilbert J. Huff, Raymond H. Moore

"Black powder is employed widely in peace and war. Its properties are therefore of considerable interest to many. The Bureau of Mines frequently is asked to furnish information on its use and safe handling in the mining and mineral industries in times of peace and is now engaged in studies of its application to the arts of war.Black powder has been the agent in many accidents - some very disastrous - and its handling and use are deemed very hazardous. The belief is widespread that the hazards are due principally to the ease with which the powder is ignited by a hot spark or flame in contradistinction to high explosives; these usually are ignited only with difficulty, and some burn incompl0tely and to a certain extent are self-extinguishing. Primary precautions, .therefore, should be taken to prevent the access of heat, spark, and flame.In black powder manufacturing operations a frequent source of disaster is the initiation of fires and explosions in the wheel mills in which the sulfur, charcoal, and nitrate are incorporated. Long experience has indicated that the wheel mill probably will fire if the powder is not kept moist enough; manufacturing supervision calls for the maintenance of a minimum moisture content, at least during the milling. Accidents occur elsewhere in the manufacturing line, and in an endeavor to minimize these, particularly those happening in corning mills, one of the writers suggested many years ago that a suitable humidity be maintained in other operations in the hope that it would serve protectively as in the wheel mill. The experience of one company for many years with this practice was favorable. It seemed desirable therefore, to explore the question experimentally."

Nov 1, 1944

By Ogden Tweto

The Leadville district, on the west flank of the Mosquito Range in central Colorado, has produced silver, zinc, lead, gold, and minor metals valued at $512,000,000. The ore deposits are in a sequence of dolomites and quartzites, Cambrian through Mississippian in age and about 500 feet thick, which is extensively intruded by porphyry sills, dikes, and plugs of Tertiary age. The sedimentary rocks and sills dip about 15°E and are broken by many faults, which are predominantly of nearnorth trend and downthrown to the west. The ore deposits are principally blanket or manto replacement deposits, but in the eastern part of the district many veins occur also. The replacement deposits are largely confined to three dolomite units in the stratigraphic sequence. Of these, the uppermost or Leadville Dolomite is the most productive. Most ore bodies are on the underside of porphyry sills and, particularly, beneath sills that occupy unconformities. Many replacement bodies have vein roots or branch from veins. The veins occupy faults and are productive mainly in the section of quartzites and dolomites and included sills. The primary ores consist principally of pyrite, marmatitic sphalerite, and galena but locally contain chalcopyrite, silver minerals, bismuth minerals, and gold. Principal gangue minerals are manganosiderite and jasperoid. The ore deposits have a crude zonal pattern centered around an intrusive center at Breece Hill, which evidently influenced ore deposition thermally. The ore deposits were oxidized to depths of several hundred feet in Miocene time. Bonanza ores mined in the early days were characterized by cerussite, cerargyrite, and embolite. Later, zinc carbonate ores were identified and mined on a large scale. The Leadville district is a complexly faulted and intruded area at the intersection of major fault systems trending N20°W and N15°E in the Mosquito Range. The intensely fractured area evidently localized igneous intrusion and subsequent mineralization. Ore solutions rose on many of the faults in the area, presumably from the same source as the porphyry magmas. Movement on these faults continued into the Pleistocene, displacing ore bodies, oxidation zones, Pliocene sediments, and glacial deposits.

Jan 1, 1968

The investigations reported herein comprise preliminary studies to evaluate large scale mining systems adaptable to the thicker oil shale deposits in the deeper central portion of the Piceance Creek Basin. The studies include an evaluation of the geology, hydrology and resources of the Basin., evaluation of a potential prototype mine site, synthesis of rock mechanics data on Green River Formation oil shale, selection and preliminary design and cost evaluation of six potential mining systems and a ranking analysis to aid in selecting the most promising system. Results of the ranking analysis indicate the following four systems to be most promising for large scale underground oil shale mining: - Chamber and pillar (using spent shale backfill) - Sublevel stoping with spent shale backfill - Sublevel stoping with full subsidence - Block caving with LHD's Recommendations for phase II are to investigate the above systems in greater detail, refine present cost data, and perform economic evaluations of oil shale mining using these systems.

Jan 1, 1975

By W. H. Kerns

The Taylor Creek lead-zinc deposit is on Taylor Creek, approximately 1-1/2 miles from tidewater, at the head of Duncan Canal, on the east side of Kupreanof Island, Petersburg district, southeastern Alaska. The property was located in 1903, and a 30-foot discovery cut was put to the west tank of the creek. Very little prospecting end developing has been done since that time. The property was examined by J. C. Roehm, associate mining engineer, Territorial Department of Mines, Juneau, Alaska, in June 1946. From exposure n the creek, a mineralized zone with possible dimensions of 1,700 feet by 1,000 feet was indicated. The general strike was northwest, and the dip was low and variable to the northwest. During September through November 1948, the Bureau of Mines conducted a project on the property. Four diamond-drill holes, totaling 770.5 linear feet, were drilled from the surface and 280 lineal feet of hand trenching done. The mineral deposit was found to occur as patches that appear to be a replacement in dolomitic limestone. The patches of mineralization are small, irregularly shaped, and irregularly distributed. Maps showing the location of the drill holes and trenches, analyses of the cores from the drill holes, and anal lee of the samples from the trenches accompany this report (see, also, appendixes A, B, and C).

Jan 1, 1950

By R. R. Faddick

A mineral slurry data hank has been compiled, containing slurry pipelining data on sixteen ores, concentrates, and tailings. The data bank it in the form of a computer print-out all they necessary system constants and headloss data for each mineral commodity. The purpose of the data bank was to assist in the development of a universal head loss correlation for mineral slurries, if such a thing exists. Present headloss correlations were tested and found to be inconsistent for the various mineral slurries. Consequently, a different approach was taken, that of compiling a library or Stanton diagrams relating friction factor and Reynolds numbers for a given slurry in a given pipe diameter. The advantages of the diagrams arc demonstrated and discussed. While this correlation shows excellent potential, it is necessary that additional work, both theoretical and experimental, be performed. In addition, two equations are given from which a design velocity may be obtained to minimize deposition or formation of bedload. The equations are based on data taken from the mineral slurry data bank.

Jan 1, 1972

By Guy Ervin, Delwin D. Blue, John E. Conley

"INTRODUCTION Extraction of alumina from various materials, such as low-grade bauxite and clay, by means of a lime-soda sinter has been the subject of a number ofinvestigations (1, 2, 3, 4, 5, 7, 9, 10, 11, 12, 13, 16, 17). 5/ in recent years, Although many of the details of these investigations are lacking, it is believed that there is one difficultly that frequently develops under certain conditions, namely, that of thickening or gelation of the slurry formed during extraction of the sinter. If gelation occurs even to a slight extent* Serious mechanical difficulties result, very low liquor recoveries are obtained, and the extraction step becomes virlually inoperable. Under 'favorable conditions, a solid gel is formed which can only be removed from the equipment with great difficulty. At the Eastern Experiment. Station of the Bureau of Mines in College Park, Md., a study of lime-soda processes was begun in November 1941. This work has included studies on low-grade bauxites, kaolin clay, and nodular diasporic clay. Gelation was most serous with kaolin clay and least with diasporic clay. As a part of the Bureau's investigation, a study was made of the effect of the pertinent variables on gelation. The results permit the selection of various sets of conditions at which gelation will not occur. These data are essential to the final selection of optimum conditions for the over-all process."

Aug 1, 1946

The Bureau of Mines is operated to assist in promoting economic development through increased efficiency in the mining, preparation, treatment, and utilization of mineral substances; to aid in conserving mineral resources through preventing waste; and to help the mining industry improve health conditions and increase safety. Accomplishment of those ends is sought through investigation of scientific, technologic, and economic problems of the, mineral industries and dissemination of resulting information. Building materials of mineral origin constitute an important product of mining, and the Bureau makes studies of these in the various fields mentioned. The following commodities come within this classification: Asbestos, anhydrite, asphalt, cement, clay and clay products, diatomite, dolomite, glass and mineral wool, granite, greenstone, gypsum, lightweight building materials, lime, limestone, magnesite, marble, sand, sand and gravel, sandstone, sand-lime brick, slate, soapstone, and trap rock.

Jan 1, 1937