Search Documents

By James H. McCutchan

The small and remote mine operators must comply with the Federal Mine Safety and Health Administration regulation requiring them to train and maintain mine rescue teams. The alternative is for the operators to contract with established teams within two hours travel time of their mine. Many of these remote operations are too far away from established teams and have too few employees to make up the necessary teams. Many cannot comply with the regulation either from a manpower or economic standpoint. The Office of Arizona State Mine Inspector, under the direction of the Honorable James H. McCutchan, State Mine Inspector, entered into a contract with the Bureau of Mines to develop the concept of a volunteer mine rescue program. This program with the assistance of the mining industry and volunteer rescue organizations, has planned and instituted a statewide volunteer mine rescue organization. The trained and equipped volunteers are stationed throughout the state and can respond to a mine emergency within the time constraints.

Jan 1, 1984

By Leslie F. Ruppert

The US Geological Survey (USGS) is currently conducting a coal resource assessment of the coalbeds and zones that are projected to provide the bulk of the nation’s resources for the next few decades. The Pittsburgh and Upper Freeport coals are the first two beds in the northern and central Appalachian basin region to undergo fully digital coal assessments. The bed-specific assessments are being carried out in partnership with the state geologic surveys of West Virginia, Ohio, Pennsylvania and Maryland. Comprehensive stratigraphic and geochemical databases have been developed for both of the beds. The extent of the bed with mined areas, structure contour, isopach, and overburden thickness maps for the Pittsburgh coal bed have been released as USGS open-file reports.

Jan 1, 1999

By Liqun Liang

Various nondestructive testing (NDT) inspection methods are available to evaluate the structural integrity of cast-in-place shafts. The widely used methods include Cross Hole Sonic Logging Testing and Low Strain Testing. Due to its advantages such as low cost, easy operation, quickness and flexibility (no need to plan ahead and prepare inspection tubes or other devices), Low Strain Test is frequently specified in quality assurance programs of many countries or when doubts arise as to the integrity of the finished shafts/piles. The method is well suited for small to middle sized shafts. However it is an indirect NDT testing method and has certain limitations. Data interpretation requires proper training, experience and judgment and, therefore, inconsistent conclusions and reporting may be provided by different testers. To avoid or reduce such inconsistencies, it is best to follow a standardized data interpretation and record classification system. In this paper, a new classification method is presented with examples. A step-by-step data evaluation and interpretation procedure is proposed with examples of real cases to help understand the LST data. The paper also makes recommendations for measures to be taken when anomalies are detected in tested production piles.

Jan 1, 2011

By A. More, J. M. Míguez, J. Bullón

In 2000 Ferroatlantica started a project with the aim to develop a new casting machine for silicon and other ferroalloys. Until now, it has been cast more than 25.000 tons of silicon for the chemical and metallurgical market. This system has improved the process yield, productivity and product quality which place?s Ferroatlantica at the top of technology development in this field. After the first presentation of the Ferroatlantica?s casting machine at Infacon X, we would like to show the improvements in the control which have permitted us to increase the lifetime of the copper and to obtain, at the end of the machine, the right product size for the customer avoiding the current necessity of crushing and sizing the lumpy metal. Furthermore, we have improved the system in relation to the obtaining of smaller granulometries at the end of casting machine. Not only is this kind of machine cost competitive for special silicon applications but also for other normal ferroalloys with different specifications of size and thickness.

Jan 1, 2007

By M. J. Gavin

Within the past three years numerous inquiries for information on oil shale have been received by the Bureau of Manes. These inquiries have been increasing to such an extent that it has seemed advisable to issue a short paper prior to the publication of a bulletin on the subject, giving a, general discussion of the subject and a comprehensive list of references, so that those interested in the details of obtaining oil from shale can find additional information without much difficulty. Some of those who desire information are interested only in a general discussion of the subject, or are not in a position to refer to books and' articles describing the industry. The material for this paper is largely derived from published information on oil shale. Much of the information is obtained-from the books and articles mentioned in the list of references, and has been compiled with the intent of furnishing information to those not interested in all the details.

Jan 1, 1921

Judicious placement of a range of geotechnical instruments was employed at the Tasmania gold mine, Beaconsfield, Tasmania, as a key strategy in the monitoring of rock mass conditions over the past four years. The range of instruments employed included vibrating wire stress-meters and hollow inclusion cells to monitor changing stress conditions, resistance wire and multipoint borehole extensometers to monitor the impact of stress changes on the integrity of the rock mass, and instrumented cable bolts and threadbar bolts to monitor the static and dynamic impact of rock mass changes on the installed ground control system. Initially the monitoring was of a qualitative nature, monitoring change from the time of installation. The value of the output was considerable when considered in relation to the ongoing seismic record which was also being monitored. It was clear from the seismic record and the monitoring results that stope blasting was the primary trigger for changing rock mass conditions. However, it was unclear how well observed behaviour was reflecting conditions anticipated by elastic numerical modelling. The latter had predicted significant stress increase in the near field of man-access footwall development. Qualitative monitoring and visual inspection did not support the modelling prediction, and this led to a program of quantitative measurement being undertaken. Measurement of the absolute stress condition in the backs of footwall development immediately adjacent to monitoring hollow inclusion cells provided the benchmark for tracking quantitative stress change. The program provided insight into the evolution of principal stress field magnitude and orientation in relation to rock mass change observed with extensometers and instrumented ground control elements, as well as providing a degree of calibration between the elastic numerical modelling and the virgin stress field. Calibrated monitoring data has also provided a useful benchmark for finite element modelling which is to be used for future mine-wide design.

Nov 25, 2010

By A. Jennings

[ ] In November 2005, Essroc Cement, part of the Italcementi Group, commissioned a long overland conveyor at their Nazareth plant in Pennsylvania. This conveyor, tagged CV-105, was designed to transport 1000 tph of limestone from the quarry to the kiln, and 400 tph of hot clinker (at 300°F) at back from the kiln to a handling facility about halfway back. Conveyor CV-105 is 8969 ft (2733 m) long. It gains 152 ft (46 m) of elevation in the first 1570 ft (480 m), then is mostly flat for the remaining 7400 ft (2250 m) (Figure 1). After the limestone is discharged at the head pulley, hot clinker is loaded onto the return side of the belt. This clinker can be discharged at one of two locations.

Jan 1, 2012

The AMIRA Code of Practice and Guidelines for Metal Accounting was developed in response to demand from a number of sponsor companies, including one major platinum producer. Since its publication in 2007, the Code has become widely accepted in the mining industry world-wide as a guide for best practice in metal accounting. With the changes in the structure of the platinum mining industry in South Africa over the last 10?15 years, in particular, the starting up of a number of small platinum producers who must have their concentrate smelted and the contained valuable metals refined by third parties, the need for metal accounting systems that are accurate and have an acceptable level of precision has become even more critical to the success of a platinum-producing operation. The current state of metal accounting in the industry is discussed, and possible areas for improved accounting and associated metallurgical efficiencies are identified.

Jan 1, 2013

By P. Brad Marchant

"To properly evaluate bioleaching as a commercial alternative for sulphide concentrate oxidation, to enhance cyanidation response, it was necessary to define and optimize critical operating variables outside of the laboratory under less than ideal conditions. A complete bioleach testing laboratory was installed at Equity Silver Mines to aid in pilot plant flowsheet development.A continuous pilot scale bioleach circuit was constructed to provide data for meaningful valuation of biotechnology on a plant scale. The important operating and design parameters for pilot plant testing are described. Plant scale feasibility and design considerations, to treat a refractory pyrite/arsenopyrite concentrate produced from flotation tailing, are discussed. 1.0 BACKGROUNDEquity Silver Mines Limited is located 37 km southeast of Houston in central British Columbia. A 70% owned subsidiary of Placer Development Limited, Equity is Canada's largest open pit silver producer. Ore reserves were estimated at 28 million tonnes grading 106 g Ag/t, 0.96 g Au/t, and 0.38% Cu from two pits, the Southern Tail and the Main Zone. Detailed geology and mineralogy has been described previously(1,2).The concentrator flowsheet consists of conventional crushing, grinding, flotation, and dewatering circuits processing 5 300 tonnes per day of new mill feed. The resultant Cu/Ag/Au concentrate is trucked to Prince Rupert for shipment to market. Mill tailing reports to a closed circuit pond from which mill process water is recycled. Details of the concentrator process have been reported( 2,3).Production in the Southern Tail pit, from July 1980 to March 1984, resulted in mill tailing averaging 0.9 g Au/t and slightly more than 20 g Ag/t. Historic data indicate that unrecovered gold is associated with arsenopyrite and silver losses with unliberated tetrahedrite or minor silve,, bearing sulphosalts. Main Zone mill tailing, which commenced production in March 1984, contains approximately 0.5 g Au/t which is probably associated by majority with silver bearing minerals and pyrite while silver losses, 30-40 g Ag/t, are associated with unliberated silver and antimony bearing minerals."

Jan 1, 1985

By R. Codell, D. L. Hughson

While benchmarking the integrated finite-volume code MULTIFLO against the analytical solution of Philip et al. (1989) for cylindrical underground openings, we found numerical simulation of dripping threshold flux consistently higher than the analytical solution for both rectangular and unstructured grids. The magnitude of error is proportional to the alpha parameter characterizing capillarity. This may bias estimates of repository performance towards non-conservatism.

Jan 1, 2000

By E. Kamon

This report summarizes completed research pertaining to the reaction of human subjects exposed to Self-Contained Breathing Apparatus (SCBA) stressors during escape conditions (viz., resistance breathing, C02 breathing, hot air breathing, and static positive facepiece positive pressure breathing) and the development of an automated breathing and metabolic simulator (ABMS). Volume I contains summarizes of the studies performed under this contract. Volume II is an appendix which contains more detailed descriptions of these studies.

Jan 1, 1984

By Charles E. Whieldon

Data on the oilfields in Mahoning, Columbiana, Carroll, Jefferson, and Harrison Counties, Ohio, were collected from scattered sources and compiled to make the information readily available to operators who may be interested in conducting secondary-recovery operations in the area. General geology, oil production, oil-productive acreage, core data, reservoir calculations by townships, and miscellaneous data and reference material are presented.

Jan 1, 1965

Draft tube circulators are now widely used instead of Pachucas for suspension of slurries in large tall tanks.Precipitators in the alumina industry are an example.Draft tube/tank diameter ratio is critical. Two independent criteria are given for optimum ratio. The hydraulic and energy relationships are defined. These require an impeller of very high specific speed. For a stable and efficient system the impeller should have aerofoil blades with a pitch angle which decreases from hub to tip.The draft tube must be matched to the impeller with inlet baffles above the impeller and flow control vanes below it. Tip recirculation must be suppressed. The tank itself should have a filleted flat bottom.Such a system exhibits the behaviour of axial flow devices with the characteristic undesirable behaviour at low flow.Installed and operating power requirements depend critically on hydraulic design and to a lesser extent on speed reducer efficiency.The problems of re-suspension have been overcome by a patented slot system which also improves behaviour at low flow to permit a more economic design. A number of other practical operating considerations are also discussed.

Jan 1, 1982

A description is given of preliminary work done to identify the problems inherent in electrochemical oxidation of metal sulphides, and particularly in the use of powder compacts as anodes in electrolysis. Lead flotation concentrate pressed into a compact can serve as an anode for direct electrowinning of lead according to the reaction PbS -7 Pb2+ +So +2e. No pYrometallurgical step is required, and sulphur is recovered in elemental form.In the experimental work, electrical conductivity of the compacts was achieved by addition of 5·5 per cent of graphite. After compaction at 10-20 tons/sq. in. the anodes were strong and remained intact throughout the electro-oxidation period. Perchlorate electrolyte was used, but fluosilicate electrolyte is also applicable. A sheet of pure lead formed the starting cathode.As anode potential increased above 1·0 V (v. SHE) PbS04 was formed in increasing amount. At 0·90 V, Pb2+ extraction efficiency was 85 per cent. Anode potential was kept low by electrolysing at 60°C and 15 mA/sq. cm., and by improving the porosity of the compact. Other metal sulphides (Zn, Fe, Cu) in the flotation concentrate also oxidize and release metal ions to the electrolyte, which would need to be purified prior to deposition of lead.Power requirement in a laboratory cell was about 0·24 kWh per lb of lead extracted.

Jan 1, 1972

By M. Kuchta, A. Newman

LKAB’s Kiruna Mine, located in northern Sweden, produces about 24 Mton of iron ore yearly using sublevel caving. For efficiency, the mine must deliver planned quantities of three ore products. We use mixed integer programming to schedule Kiruna’s operations, specifically, which production blocks should be mined, and when they should be mined to minimize deviations from planned production quantities while adhering to mining restrictions (e.g., sequencing). A new production block database and a well-formulated mixed integer programming model dramatically reduce the size of the original problem; in less than ten minutes we generate five-year schedules with time fidelity of months.

Jan 1, 2002

By Tom Snyder, John Brulia

Part 4 is the final article by the authors on hazardous materials (HM)transportation safety and compliance for U.S. shippers and carriers who offer and transport commercial explosives in commerce on public highways. This article covers hazardous materials (HM) cargo segregation and securement of non-bulk packaged explosives.

Jan 1, 2015

By Rolf Katzenbach

The principle questions related to the design of deep foundations especially in soft soils are the stability and the cost optimised settlement reduction to prevent possible damages and to minimise the deformations of the adjacent infrastructure. The present develop­ments in the design of deep foundations lead to the design approach of the Combined Pile-Raft Foundation (CPRF) which offers a lot of new possibilities, e.g. the utilisation of the CPRF for horizontal loading or the use of the subsoil as a geothermal storage system.

Jan 1, 2006

By I Mason, A Wellington, J Hargreaves

Many people are familiar with the use of marine echo sounders which are used by fishermen to monitor water depth and locate schools of fish. Similar technology has recently been used in some West Australian mines to provide detailed maps of ore contacts and other geological structures. Whilst drillhole intersections provide details of the location of a contact at a point, echo sounding can be used to obtain a continuous profile of the contact. A series of profiles together with drillhole intersection data can be used to build a more accurate geological model than can be inferred from drillhole intersections alone. The benefits of this are more complete ore extraction, less dilution and the ability to make more informed financial decisions. This paper presents a case history which demonstrates the successful application of the technology.

Jan 1, 2000

By E. R. Maize

[In report of Investigations 3452,5/ baling with roof movement in the Crucible mine, reference was made do to the fact tart timber decay was being studied at the time of writing. This roper, written after completion of that study, describes s the work and summarizes the data obtained. When the study of roof movement as begun at Crucible two ideas were advanced on decay Of timber by some of the officials: (1) That timber decay vas unusually rapid in the Crucible mine, and (2) that timber coated with rock dust decayed more rapidly than those teat were not so coated. There yore no records by which these ideas could be tested, and it appeared wise to make a limited; investigation particularly of the effect of rock dusting on decay, as rock dusting is an important means of preventing coal-dust explosions.]

Jan 1, 1940

By Chris Tattersall, Tomyuki Kudo, Peter Raleigh, Nestor Garavelli, Steve Redmond, Michael J. Lehnen

Twin bore running tunnels driven approximately 4,500 route feet by a Mitsubishi Heavy Industries (MHI) EPB Tunnel Boring Machine link the West Portal and East Portal on this complex Light Rail Project. One third along the way, the TBM arrives at the Beacon Hill Station which is the deepest underground “binocular” station of its kind in North America and then “walks-across” the station to be re-launched on the other side to complete the drive. This paper discusses briefly the layout and design considerations but then focuses more deeply on the approach by the Contractor to drive and supply the tunnel. The paper addresses the approach used to launch, re-launch and recover the TBM and touches briefly on muck volume control and monitoring plus settlement monitoring and the performance achieved. Also of interest is a unique solution to a difficult launch situation involving a secant pile tieback wall designed with several rows of double I-beam steel walers spanning the eye at the West Portal under the I-5 freeway.

Jan 1, 2007