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By James Westfield

A brief résumé follows of activities of the Division of Coal-Mine Inspection that have had a favorable effect on health, safety, and the reduction of injuries at coal mines: 1. The Federal Mine Safety Code fur Bituminous Coal and Lignite Mines of the United States was issued originally by the Director of the Bureau of Mines on July 24, 1946, after consulting with management and labor representatives of the coal-mining industry. The code has been used by Federal coal-mine inspectors while inspecting bituminous-coal and lignite mines as a basis for determining the existence of unhealthful and unsafe conditions and practices in these mines. A revised code was issued by the Secretary of the Interior on October 8, 1953, after further consultations with representatives of management and mine workers and was incorporated by reference in the 1952 and subsequent bituminous -coal wage agreements. The agreement of May 29, 1946, between the Secretary of the Interior, acting as Coal Mines Administrator under authority of Executive Order 9728, and the United Mine Workers of America, covering bituminous-coal and lignite mines in Government possession, charged Federal coal-mine inspectors with the responsibility of making periodic investigations of the mines and reportin; to the Coal Mines Administrator any violations of the Federal Minis Safety Code. Federal coal-mine inspectors also had temporary authority to close mines found to be imminently dangerous, but such authority under Executive Order 9728 was removed on June 30, 1947, when Government control of the mines was terminated.

Jan 1, 1960

By Walter B. Lenhart

This paper is one of a series on milling methods and costs being. published by the Bureau of Mines. The milling practices and special problems relating to grinding, tailings disposal, and choice of a treatment process at the Cardinal mill are discussed. The property of the Cardinal Gold Mining Co. is about 18 miles southwest of the town of Bishop, Inyo County, Calif., at an altitude of approximately 8,500 feet. The camp has been designated Bishop Creek by the postal authorities. The property comprises 33 mining claims, including fractions and millsite in sections 19, 20, 29, and 30, T. 8 S., R. 31 E. These claims are located in a general way along the strike of a band of quartzite.

Jan 1, 1938

By M. J. Howes

The high degree of mechanisation, which is mainly diesel-powered, has a significant effect on heat loads; heat output from this source often exceeds the heat flow from the surrounding rock. The extensive use of diesel-powered equipment also influences ventilation rates and minimum values are necessary to ensure that emissions of diesel exhaust are adequately diluted. Many Australian mines are in subtropical or tropical areas with high ambient wet- and dry-bulb temperatures on surface. This, coupled with the large amount of heat from mechanisation, usually means that refrigeration is required at much shallower depths. A secondary problem is associated with the definition of acceptable thermal environment conditions, which are sometimes based on the assumption of no air movement. This gives rise to very stringent thermal environment acceptance criteria, which, in some areas, would prohibit work on surface, let alone underground

Jun 12, 1905

By Zephaniah Varley, Satoshi Akai, Richard Sage, Steve Redmond, Mike Murray, Rohit Shetty, Gerald Skalla

One would be hard pressed to find another project as complex as this one given its configuration, the variety of issues to address and the required construction techniques. Contract C710 is currently under construction as part of Sound Transit’s Link Light Rail, connecting downtown Seattle with Sea-Tac Airport. The paper describes the construction-to-date of the deep mined station under Beacon Hill using the Sequential Excavation Method (SEM). This deep “binocular” station is being mined through some of the most challenging soft ground conditions in the USA. The excavated volume of the station is approximately 60,000 cy (46,000 m3) and the station comprises a variety of geometries and cross sections ranging from 235 sf (22 m2) up to 1,670 sf (155 m2). This underground complex includes platform, concourse, cross-passage and emergency ventilation tunnels together with station egress and ventilation shafts. Various excavation sequences are in use for the different tunnels including the twin-sidewall drifts for the impressive45 ft (13.7 m) wide by 42 ft ( 12.8 m) high concourse cross adits. This station has two train platforms approximately 165 feet (50m) below the surface. This station, constructed in highly variable glacial deposits including water bearing sands and silts approximately 50 ft below multiple perched water tables in an urban setting, creates a very unique and challenging situation. The ground is being managed with various types of ground improvements such as jet grouting and vacuum assisted deep dewatering wells from the surface, and from underground by use of “SEM Tool-box Items” such as barrel vault canopy, grouted pipe and rebar spiling, chemical grout,

Jan 1, 2007

Two structurally and mineralogically distinct sulphiderich veins cross-cutting the disseminated sulphides of the Nairne Pyrite Member appear to be products of local remobilization of sulphides under fracture-induced free energy gradients during regional metamorphism and tectonic deformation.The contrasting mineralogy of the two vein types may have arisen as a result of differences in the structural orientation of the veins and!or the relative ages of the veins.

Jan 1, 1969

This paper describes a proposal to reopen the Sylvia gold mine for underground exploration and development for an initial production of 10 000 tpa. A combination of trackless mining equipment and railtrack would be utilised for development with ore extraction being carried out by undercut and fill methods. The use of the smallest LHD units for mucking, and rail track for the main haulage together with airleg drilling will form the basis for development and stoping. The proposal has been subjected to an environmental impact assessment report to evaluate the impacts of the proposal on the natural and social environment in the area.

Jan 1, 1987

By J. A. Stewart

"A common problem in the mining industry involves the overloading of established conveyor systems. This overloading can have a number of causes, such as new production technology or a changing market condition which increases demand. An overloaded system usually spells disaster and leads to clean-up problems, equipment failures and lost production. The Cape Breton Development Corporation's Lingan Mine had a serious overloading situation on its underground coal clearance system, and equipment was being damaged and production was being lost. It was rectified, in part, by increasing the coal clearance capacity through the use of booster conveyors. This paper discusses the problems which led to this situation, the booster concept and the installation of the first unit at the Lingan Mine.IntroductionThe Lingan Mine is a submarine coal mining operation with an annual production of 1.5 million tonnes from three advancing longwalls. Coal is conveyed 3400m up a 13% slope to the surface. Designed and installed in the early 1970s, the system's 820-tonne/hour design initially proved adequate; however, by the late 1970sthe system was handling surge loads of 1640 tonnes per hour due to the introduction of new face equipment.The coal clearance system consisted of three 485-Kw, two 210-Kw and one 105-Kw conveyors. Each conveyor was designed for 820 tonnes per hour using 1050-mm, Type 10 belt with a 35-degree troughing profile.There were many effects of the overloading on the system:• Loading beyond the physical capacity of the belt resulted in spillage along the conveyor, which increased operational and maintenance costs.• Overloading of the drive components resulted in premature equipment failures.• Spillage at the drive pulley often resulted in damage to the belt and pulley lagging and, under extreme conditions, the conveyor would require partial unloading before it would operate. This was a particular problem under wet conditions because the 485-Kw conveyor drives were fitted with single-drive drums."

Jan 1, 1982

By R. E. Johnson

Seventy years after the start of the Industrial Revolution in Great Britain, as reckoned from Arkwright's water frame patented in 1769, there was a significant development of the metallurgical industry in Virginia. In Britain, crucible steel had been rediscovered by Benjamin Huntsman in 17~0, and this made spring and tool steel more generally available. The metal-turning, screw-cutting lathe, including the basic principles recognized in today's engine lathe, was developed by Henry Maudslay about 1797. Wrought iron, as manufactured by Henry Cort's process patented in 1784, was readily available. Richard Trevithick's highpressure steam locomotive had met its test on the Pennydarren tramroad in 1804, and George Stephenson had built his famous Rocket, along with several other locomotives, at Newcastle around 1828. Puddling furnaces and a rolling mill had been placed in operation at the Tredegar Iron Works in Glyn Sirhowy, Monmouthshire, Wales, in 1807. In the United States, expanding commerce and a growing population resulted in continuing development from the Chesapeake to Virginia's Blue Ridge, and this demanded improved means of transportation. Ore deposits rich in hematite had been found in Virginia's Piedmont during the Colonial period, and a number of blast furnaces now dotted that area. The products of these operations were mostly pots, kettles, stove parts and like items for local trade. The James River and Kanawha Canal was incorporated in January 1785. Its eastern leg, winding along the slope of the high bluffs overlooking the river, was completed about 1800. About two dozen railroads were chartered in Virginia between 1830 and 1837. With expanding population and steady industrial development came a need for metallurgical products. Throughout the eastern United States, numerous metallurgical enterprises sprang up, and many of these flourished. The purpose of this article is to outline the development of one Southern metallurgical company, the Tredegar Iron Works, which was to have a significant impact on the industrial development of Virginia and the fighting of the American Civil War. Although the Tredegar Iron Works no longer exists, remnants of the early operations have been restored, and the current status of the site is also presented.

Jan 1, 1999

By J. -P. Saindon, L. D. Nel, A. E. Hall, S. G. Hardcastle

"This paper reports on an investigation into gas and dust concentrations in Ruttan Mine's exhaust air. The values obtained indicate that there is excellent potential to recirculate approximately 25% of the hot exhaust air into the intake air to reduce winter heating costs. Contaminant concentrations vary significantly during the course of the working shift and decrease in the mine exhaust system as the air returns to surface. A proposed on-line control system is outlined which would permit recirculation to be implemented with a pay-back period of less than two years. IntroductionIncreased energy costs and depressed mineral prices have resulted in mines, which use winter ventilation air heating, reviewing their systems to try to reduce costs. Heating costs can be significant, for example, Potash Corporation of Saskatchewan spends an average of $580,000 per mine per year and Ruttan mine spends approximately $IM per year on propane for its direct-fired heating system.Several method s of reducing heating costs have been considered and the following have potential application.Heat Exchange Between Exhaust andIntakeThis is usually accomplished by run-round glycol systems. The system is limited by ice formation on the coils in wet exhaust air and by the low exhaust air temperature, usually l0ºC. It also requires close proximity of the intake and exhaust airways to ma~e the cost of the connecting pipeline and pump systems economic . A feasibility study by Inco's Thompson operation reported that a proposed system of this type had a 19-year payback period and was, therefore, uneconomic. Potash Corporation of Saskatchewan is currently investigating plastic heat exchangers for a trial system because of corrosion on metal exchangers. It has the advantage of a 17°C exhaust temperature and relatively dry exhaust air.Waste Heat ReclamationThe waste heat from compressors and hoists can be used for heating in some mines. The feasibility of such a system depends on the individual layout and the proximity of the heat source to the inlet airway. Other mines have considered using the exhaust air in greenhouses to provide a cash crop."

Jan 1, 1988

By Jason N. Scott

CFA piling is a ?blind? construction process that relies heavily on the rig instrumentation to produce sound piles. If the data measured and recorded during construction can be made available to engineers and managers within hours after construction then there are many economic and quality control benefits that can be realised. A state of the art CFA instrumentation and data management process has been developed in the UK. The key components of the instrumentation, GSM data service and the central database are described. Many benefits to the business have been realised and, where possible, these are quantified.

Jan 1, 2006

By J. H. Hedges

During the World War Leadville was an important producer of manganese and maganiferous ores for then steel industry. Normally, the market for these ores is limited to the requirements of the local steel mill at Pueblo for low-grade ores used in making, basic pig iron containing 1 to 2 percent Mr and spiegoloison containing 20 percent Mn, but during the war and a brief period of postwar readjustment, a good deal of 25- to 40-percent manganese ore qua shipped to in-stern steel-manufacturing centers. Throughout the active life of the camp, manganiferous iron ore carrying a little silver and lead and sometimes as such as 35 percent Mn was chipped to load smelters for flux. The total reordered production is 936,024 tons of metallurgical ore shinned to steel mills and 2,576,514 tons of fluxing ore, much of it of metallurgical grade.

Jan 1, 1940

By F. Rosenblum, P. Spira

"Techniques were developed to determine the oxygen demand of sulphide ore pulps in the laboratory and in concentrators. The effect of variables which influence oxygen demand was studied, and it is shown that the oxygen demand is a measure of the degree of oxidation of the sulphide surfaces. It is suggested that in investigating the significance of oxygen in flotation, the oxygen demand of the pulp is a more suitable parameter than the dissolved oxygen content.Oxygen demand measurements are being carried out with a view to determining the effect of aeration on mill metallurgy and devising improved methods of predicting aeration requirements of sulphide ores.The importance of pulp oxidation in the flotation of massive sulphide ores has long been recognized. At the Noranda concentrator, chalcopyrite could not be floated satisfactorily without a pre-flotation aeration step because the necessary dissolved oxygen was consumed by the large amount of pyrrhotite in the ore. With aeration, pyrrhotite and pyrite were depressed by surface •oxidization, and the resulting thiosulphate level in solution gave a good indication of the end of useful aeration. 1'he present study was prompted by the need to find an alternative criterion for cases where recycled mill water may contain a relatively high concentration of thiosulphate. Preliminary experiments suggested that the rate of oxygen uptake by the pulp -its oxygen demand -might be a practical measure of the end point of aeration as well as a significant parameter in the flotation of massive sulphide ores.Although it has long been realized that oxygen is an important variable in flotation, analytical difficulties precluded detailed plant investigations. Measurements of' dissolved oxygen in mill pulps were first reported by Ralston(i) in 1929. A titration method was used, and because of the delay occasioned by the preparation of clear solution samples, the values obtained were believed to be low. It was quite evident, however, that pulps in the grinding circuit had a lower oxygen content than in flotation. More recently, Woodcock(2,3) used a polarographic probe to carry out oxygen surveys in six Australian concentrators and he generally observed a similar pattern. A large number of other solution parameters were monitored, such as pH, redox potential, reducing power, and reagent and metal concentrations, with the aim of detecting correlations among the measured variables. A few potentin.lly useful relationships were found ""or specific operations in certain plants."

Jan 1, 1974

By George A. Laird

I. INTRODUCTION. THIS old and once famous district played, through its enormous production of silver and gold, an important part in the history of the State of San Luis Potosi. According to a pamphlet prepared under the direction of the Governor of the State, Sr. Don Blas Escontria, and presented to the visiting members of the Institute during the Mexican meeting of 1901, this district is situated 20 km. east of the city of San Luis Potosi, in a range of mountains of moderate height, extending 135 km. N. and S., and 16 km. E. and W.; and the mineralized area hitherto developed is about 600,000 sq. m. The history of the district,. as given by the record dated 1778, and formerly kept in the San Francisco convent, says that it was discovered in 1575 by Sr. Don Pedro Irarte, and adds that the city of San Luis Rey de Francisco del Potosi received its name (in allusion to the famous Potosi mines in Bolivia) by reason of the remarkable productiveness of its gold- and silver-mines in the first period of their exploration, during which they paid to the Crown, as " quintos " (the fifth part of the product), $97,000,000, as appears from the accounts of the royal treasury. The amount of the quientos paid during the " bonanza period " of 80 years was $72,000,000. The larger sum first mentioned probably represents a longer series of years. But either will suffice to indicate the great wealth of the mines. In 1663, the decadence of the industry began with the caving¬ in of several mines, concerning which the record of 1778, al¬ready cited, says, in substance, that on Good Friday one of the owners in the enterprise, in view of the unfavorable prospect of a lawsuit in which he was engaged, set fire to the timbers supporting the underground galleries and workings of the San

Jan 1, 1905

By A. C. Smith

The U.S. Bureau of Mines constructed a large-scaJe facility to study the self-heating of a large coal mass under conditions that simulate a gob area of a mine. The insulated coal chamber can hold up to 13 short tons (st) of coal and is provided with a forced ventilation system and computer-controlled temperature and gas measurement systems to monitor the heat and mass transfer phenomena that occur in the coalbed. Three experiments were completed with high-volatile C bituminous coals that exhibited high spontaneous combustion potentials in laboratory-scale tests. In the first two tests, a sustained heating was not achieved. In the third test, temperatures throughout the coalbed increased steadily from the start, with thermal runaway occurring near the center of the coalbed after 23 days. The thermal reaction wne then moved toward the front of the coalbed. The results of these tests showed that the self-heating of a large coal mass depends not just on the reactivity of the coal, but also on the particle size of the coal, the freshness of the coal surfaces, the heat-of-wetting effect, and the availability of O2 at optimum ventilation rates.

Jan 1, 1991

By M. G. Zabetakis, T. D. Moore

The use of a partially slotted 6.5-inch-inside-diameter vertical pipe to remove methane from a longwall gob area at a depth of 2,260 feet in the Pocahontas No. 3 coalbed ms investigated. The value of gas removed by such a pipe under free-flow conditions was found to equal the cost of the installation in this case. Approximately 25 percent of the available methane passed through the pipe without the use of an exhauster; an additional 10 percent was removed when an exhauster was employed. The diversion of methane through a vertical slotted pipe to the surface permitted the use of increased mining rates and decreased the ventilation air requirements.

Jan 1, 1972

By C. F. Gleeson, D. G. Sheehan

"The results of humus and overburden geochemical surveys over the Doyon, Bousquet and Page-Williams gold ore deposits are presented.These studies show that humus sampling for gold gives negative results over the Doyon deposit. The lack of response is probably caused by the presence of 1 m of relatively impermeable glaciolacustrine clay and silt that overlies 1 m to 2 m of till over the surface expression of the ore zone. By contrast, positive responses for gold occur in humus samples over the Page Williams A and C gold deposits. The ""A"" ore zone is covered by several metres of exotic calcareous till over 0.5 m to 1 m of older, locally derived till. Anomalous values for gold in humus range from 10 to 35 ppb over the orebody. Overburden over the ""C"" ore zones is much thinner, generally it consists of less than 2 m of sandy till. Trenching humus anomalies that range from 10 to 1360ppb Au uncovered the gold mineralization. The geochemical dispersal trains in till from the Doyon orebody and the Page-Williams ""A"" zone are relatively short (i.e. less than 200 m) because both deposits occur in the lee of bedrock highs that shielded them from extensive glacial quarrying. Dispersal trains from all three pyritic gold deposits can be defined using either the fine fraction or heavy mineral fraction of the till.The intensity of the gold in till anomalies over the ore zones is variable. Therefore, it would be misleading to attach rigid significant threshold gold values to overburden drilling results. Each case must be evaluated based on bedrock topography, sample density, overburden type, thickness of till, as well as size, type and orientation of the target exposed to glacial erosion."

Jan 1, 1987

Waitemata Tectonic Event(25 Ma ago) created a subduction system from the northeast of Northland, causing: (1) the emplacement of the Northland Allochthon (24-23 Ma) which provided argillaceous limestone and serpentine to Northland, and minor copper to both there and East Cape (located off Northland then); and (2) Northland volcanism (from 22 Ma), which lacked economic mineralisation. The Kiwitahi Tectonic Event (1714 Ma) caused: (1) a realignment of volcanism - from coastal western Northland, to west of the Hauraki Plains (Kiwitahi); (2) a start to the migration southwards from Northland of (a) the Alpine Fault System towards Marlborough today, (b) subduction towards Cook Strait, and (c) volcanism towards Taranaki-to-Bay of Plenty (initially through Coromandel, Kiwitahi, and offshore west coast); and (3) a start to rhyolitic volcanism & associated hydrothermal activity. The latter caused epithermal mineralisation, providing in Coromandel the best known North Island metalliferous deposits. Andesitic volcanism has been active in both of these two contrasting, subequal belts since 22 Ma. Rhyolitic volcanism and hydrothermal activity was wholly restricted to the eastern Marshall Belt, with an abrupt limit to economic mineralisation at the Volcanic Divide (within Hauraki Plains) and a major change there to basaltic volcanism of the western Searle Belt. The Kaimai Tectonic Event (5-1.5 Ma) caused: (1) a temporary reversal in volcanic migration in the Searle Belt, and a duplication of rhyolitic & hydrothermal activity at Waihi (Marshall Belt); (2) the rotational rifting of both the Central Volcanic Region (by 30¦) and the Hauraki Rift (10¦), causing major curvature of the North Island and New Zealand, and the transfer of the offshore subduction system from Coromandel to East Coast; and (3) an effective end to Coromandel mineralisation. Post-Kaimai Volcanism (1.5-0 Ma) included: (1) andesitic volcanism in the Searle Belt, yielding the western coastal titanomagnetite deposits; and (2) andesitic, and rhyolitic & hydrothermal activity in the Marshall Belt - the latter providing geothermal energy, sulphur, and pumice/perlite deposits. Post-Subduction (Intraplate) Volcanism (10-0 Ma) developed in a steadily expanding northwest region of relative tectonic quiescence, as subduction and its volcanism migrated southwards. Intraplate volcanism was predominantly basaltic, providing excellent aggregate; but less common rhyolitic & hydrothermal activity provided geothermal potential and mercury at Ngawha and at Puhipuhi, and halloysitic clays of extreme brightness elsewhere in Northland. This volcanism has reached as far SE as Mayor Island, providing an early New Zealand mineral resource - obsidian.

Jan 1, 1997

The aim of this investigation was to study the influence that varying production rates have on iron sinter quality. This was done by performing sinter pot tests at different pressure drops over the sinter bed, namely 11 kPa and 15 kPa (for 500 mm total bed depths). During each of the sintering processes temperature-time profiles were recorded of the top, middle and bottom layers of the sinter bed. On completion of the sinter process the sinter cakes were divided into top, middle and bottom layers. The physical properties of each layer were subsequently characterized by performing a tumbler test and a sieve analysis. A comprehensive mineralogical study was also conducted on each layer. This study revealed that sinters of similar cold strength could be produced under the examined production rates. However, a higher production rate was accompanied by an increased amount of fines. The cold strengths of both sinters significantly increased from the top layer to the bottom layer of the sinter bed. This strength variation is not related in any simple way to the phase composition. Keywords: Sinter, sinter bed, production rate, phase composition, cold strength, tumbler index, sieve analysis, temperature-time profile

Jan 1, 2003

By K. H. Johnston

This guide was written to furnish the coal industry with a description of techniques, instruments, and clues on how to find abandoned oil and gas wells that have penetrated coal seams. The report includes specific information on searching techniques currently in use by several coal mining companies, gas-transmission companies, and waterflood operators, as well as information on State agencies responsible for the enforcement of laws and the preservation and distribution of data pertaining to the drilling, development, and abandonment of oil and gas wells. Comparative tests were performed with several commercial electronic metal detectors to determine the feasibility of using them to aid in the search for abandoned wells and to determine the instrument most suited for that particular use. The role of methane detectors to locate abandoned wells is described, including a case history. Tests were made to develop an efficient procedure to follow in systematically searching an area for metallic clues or hydrocarbon evidence to abandoned wells. The guide describes, in detail, a search sequence, including the collection of basic data, preparation of the selected area, and the physical search. Methods are given for evaluating the results.

Jan 1, 1973

By J. Shang, P. Howarth, B. Morris

Tailings from the nickel refinery in Copper Cliff, Ontario, consist of fine silicates mixed with a variable amount of conductive and magnetic minerals mainly associated with sulphides and iron oxides. Subsequent oxidation of sulphide- rich phases within the tailings results in the formation of an acidic leachate that may contain significant concentrations of trace metals. Mapping the spatial distribution of regions of higher sulphide concentration therefore provides insight into the distribution of the acidgenerating potential within the tailings. Electrical conductivity is constrained by two parameters — the concentration of metallic sulphides and the ionic concentration of acid in groundwater. Magnetic susceptibility is directly related to the pyrrhotite and magnetite content. It is proposed that combining information derived from airborne electromagnetic and magnetic surveys can provide an indication of metallic sulphide distribution. Preliminary investigations of airborne electromagnetic and magnetic data acquired concurrently over the sulphide-rich Copper Cliff tailings site reveal that these parameters can provide information on mine tailing extent and permit separation of tailings with varying compositional and alteration levels. Airborne geophysical data provide information about the subsurface while a digital elevation model (DEM) and hyperspectral imagery record surface conditions. Integration of the two data sets can reduce ambiguity when interpreting mine tailing distributions and their subsequent alterations.

Jan 1, 2001