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By V. R. Miller

The Bureau of Mines investigated methods for testing the tensile and sheer strength of cast specimens of bulk solder and of soldered joints in order to increase the strength and extend the useful temperature range of soft solders. A spread-area test for determining the wettability of solder on copper surfaces was developed. Mannitol was used as a flux in spread tests to control spreading and to avoid plating, etching, and other side effects of regular fluxes. Data on commercial and high-purity solders obtained by these methods show more consistency than those reported by others from similar tests.

Jan 1, 1967

By A H. Clemens, P Lindsay

Acid producing potential static tests have been undertaken on sample lithologies from New Zealand coal mines, to rank the lithogies into acid producing waste rock and stable non-acid producing waste rock. Results indicated that the main acid producing waste rock in the Waikato coal region are the marine Whaingaroa siltstone and the Glen Massey formations and the main alkaline producing lithologies were the Tauranga group volcanic-derived sediments (A & D) and the Mesozoic basement. Coal ash analysis of 28 samples from 28 mines have also been analysed for reactive S percentage and their base potential has been quantified by the chemical index of alteration (CIA). The results provide mine management in the Waikato Coal region with a classification of problematic and stable waste rock types. XRF and CIA values determined from wash drill cuttings would provide a method of determining waste rock volumes and magnitude of palaeo-weathering underground.

Jan 1, 1999

By Jacob Carr, Chenming Zhou, Nicholas Damiano, James Noll, Jingcheng Li

Machine-related injuries are one of the major safety concerns in underground coal mines. Severe injuries and fatalities occur when a miner is struck, crushed, or pinned by mining equipment such as a continuous mining machine (CMM), shuttle car, or a scoop. Proximity detection systems (PDSs) have been applied in mining to reduce these types of injuries and fatalities. All of the PDSs that are currently approved by the Mine Safety and Health Administration (MSHA) for use in underground coal mines are magnetic-field based and could be affected by metallic objects such as trailing cables. Researchers from the National Institute for Occupational Safety and Health (NIOSH) investigated the influence of trailing cables on the performance of PDSs. In particular, the magnetic field coupled from proximity system generators to a de-energized trailing cable was characterized. The results show that significant energy can be coupled from the proximity system generators to a trailing cable when there is a closed loop in the cable. The effect on PDS performance from the magnetic field radiated around an energized trailing cable was also quantified for different current amplitudes in the cable. It is shown that the magnetic field caused by the electric current in the trailing cable mainly consists of a 60-Hz signal and its harmonics which causes little interference to the PDS. The results presented in this paper can help PDS manufacturers to design better systems that are more immune to these effects.

By K. Saikiran, A. R. Nalla

Longwall management, regular shield maintenance, and evaluation of ground control problems can be performed using real-time shield monitoring program. Based on real-time shield pressure data, evaluation of intensity and interval of periodic weighting, estimation of time-dependent pressure increase and the effects of geologic anomalies can be obtained. In this study, full-face shield pressure data of over 457 m (1,500 feet) of face advancement is analyzed to evaluate shield response in the presence of surface lineaments, floor undulations, and multiple main roofs. Shield pressure increase due to web cutting is also correlated with setting pressure during periodic weighting and normal time. In addition, time-dependent pressure increase rate on Sundays and holidays is also correlated with time average pressure and the location of previous periodic weighting.

Jan 1, 2000

By Claudia Monreal L., Dafne Herreros

"The Geological Modeling is the undisputed point of split of any type of mining method, the effect that the vision and experience of the geologists is propagated trough the development of the project and is an important part of the final success. The collection of information is taken in stages. In earlier stages uses the greater part of the budget and the strategy to store and manage this data collection, as its performing will define the destiny of the deposit and of the business. With this background the geology and its modeling receive great attention from the industry and care providers being a fertile field in research and innovation. "

Sep 1, 2017

By Charles A. Bankston, John C. Rowley, Robert J. Hanold, Joseph W. Neudecker

The basic concepts and processes of soil and rock melting as applied to excavation technology are reviewed. The electrically heated, small diameter prototype penetrator development sequence is presented. Emphasis is placed on the different methods of handling the fluid rock and soil melts and their significance in providing new solutions in hole support and debris handling problems. The refractory materials requirements, penetrator life and electrical heater technology are presented. Consolidating penetrators, which form stable glass-lined holes in low density rocks and soils, require no debris removal and will find applications in horizontal holes for utilities, cables, and pipeline installations. Extruding penetrators are being developed to make holes in dense, hard rocks. Melt is conditioned into a variety of debris forms, i.e., glass rods, pellets or rock wool, selected to match appropriate debris handling systems. Unique use in drilling into very hot rock or magma for geothermal exploration or production wells is projected. Some of the results of laboratory and field tests of these devices are compared with theoretically derived operating performance. Coring-consolidating penetrators for geological sampling in alluvium are projected to larger diameter self-propelled and guided coring devices for prospecting along proposed tunnel alignments. Application to the melting of annular shafts for pipeline support piles in difficult conditions such as permafrost has been scoped. Conceptual design studies of large diameter tunneling equipment have indicated the system contributions and economic aspects of rock melting relative to material comminution, wall and roof support and materials handling.

Jan 1, 1974

By F. Mucciardi

While flash smelting and converting are capturing a greater share of the market, injection through circular injectors will remain with us for the foreseeable future. The use of top lances for injection is a key feature in several processes (e.g. Mitsubishi, Ausmelt). Tuyeres, on the other hand, are incorporated into a number of processes (e.g. Noranda, Peirce-Smith). To date no lances or tuyeres are cooled by an external source. The reagent provides the bulk of the cooling. With limited cooling, it is normal to have substantial wear on the nozzles - especially in the case of lances. To overcome the issue of wear, a new patented injector (lance or tuyere) has been developed by Noranda and McGill University. This novel unit is based on heat pipe technology. It can operate for an extended period of time without wearing. Enhanced lance/tuyere life is achieved by operating the injector at a low enough temperature that promotes the formation of a thin frozen layer on the outer body of the unit. The vaporizing and condensing substance within the unit acts to cool' the high heat flux portions and dissipate the heat to areas of low heat flux outside the vessel. A fairly large number of tests have been conducted with a prototype unit. The tests have shown that the heat pipe lance is a viable unit. In this paper is detailed a test which illustrates how the lance functions when pure oxygen is injected into copper matte. In addition, the findings from a basic study of a heat pipe in high heat flux environments are also presented.

Jan 1, 1999

By C. E. Brechtel

This project describes the design and testing of large face ventilation systems for oil shale mining. A design data base was generated by reviewing general industry practice, oil shale industry planning, and technical literature. Conceptual designs for seven different systems were developed and evaluated for suitability. A large, free-standing, jet fan and reversible fan with rigid duct were selected for fabrication and testing. The two systems were field tested in a dead-end heading 55 ft wide by 30 ft high and 320 ft long. System performance was optimized using measurements of air flow direction and air velocity. Total system performance was then measured using SF6 tracer gas released to simulate blast fumes, hot diesel exhaust, methane layering and methane from a blasted muckpile. Field testing indicated that both systems delivered similar performance. The jet fan offered some clear advantages because of its mobility, ease of oper-ation and lower power requirement. It also offered some functional advantages in ventilating for methane because of it high average velocity.

Jan 1, 1985

WHILE in the employ of the Broken Hill Associated Smelters and the Electrolytic Zinc Oompanies at their South Melbourne Research Station, the writer was detailed to investigate the principles underlying the Parkes Process with a view of determining:1. The Interdependence of the variables:(a) Quantity of zinc required per charge,(b) Temperature of stirring of each zincing,(c) Silver content of the bullion after first zinculg,(d) Silver content of the bullion after second zincing,(e) Silver grade of the crusts produced for retorting, with reference to the method of working the Parkes Process then in operation at Port Pirie.2. The possibility of effecting improvements in the Port Pirie practice of desilverising, especially with respect to:(a) Silver grade of the crusts produced for retorting.(b) Quantity of zinc required per charge.The method of desilverising in practice at Port Pirie was a two-stage zincing.In both zincings the bullion was cooled to its solidification temperature and the silver crusts which separated from the lead were completely removed.The crusts from the first zincing were retorted, and the crusts from the second zincing were returned to the first zincing of the next charge.

Jan 1, 1925

This paper gives a general description of mining operations at the Mount Morgan Open Cut. Certain features such as blast hole diamond drilling, which may be of particular interest, have been described in detail. The paper is covered by the following headings:-1. History2. Ore Reserves and Production Data3. Mining Methodsa. Design and Layout of the Open Cut.b. Overburden and Ore Breaking.c. Loading and Transport of Ore and Overburden.d. Transport of Men and Supplies.e. Survey and Assay.f. Drainage.4. Power and Compressed Air5. Mining Equipmenta. Shovels.b. Mine Transport.c. Dozer Tractors.d. Drill Shop.6. CostsHISTORYIn order to appreciate fully the design of the present Open Cut at Mount Morgan, a brief outline of the Mine's history and past mining methods is necessary. In 1882 the Mount Morgan Syndicate began to mine this large gold-copper orebody by small hill-top quarries...

Jan 1, 1952

This paper contains an account of some creep tests on electrolytic lead and some of its alloys. The stresses used in determining creep were 500, 350, and 200 lb. per sq.' in. The alloys contained silver, bismuth, tellurium, antimony and zinc respectively. All were castin vacuo, and tested "as rolled." Tests were done also on electrolytic lead which had been cast in air.The electrolytic lead contained 0.0005% total impurities.The preparation and vacuum casting of this lead have been described in a previous paper in this series. The preparation of the alloys, and the air casting of the electrolytic lead, are described in the next section.EXPERIMENTAL PROCEDURE.Every effort was made to keep the vacuum-cast specimens from contact with the atmosphere throughout their history.The ingots were stored eIther in a vacuum desiccator or immersed in heavy oil. The creep specimens were coated with vaseline except during rolling, etching and photography, which involved exposure to the atmosphere for about 45 minutes all told.It is not claimed that vaseline is a perfect shield against the intrusion of atmospheric gases. Possibly during the months that some tests were in progress the gases diffused through the vaseline and gained a limited access to the lead.Nevertheless, the use of vaseline gave protection that brought the tests nearer the ideal at which the author aimed, *Research Fellow, Dept. of Metallurgy, University of Melbourne.

Jan 1, 1936

Bio-Oxidation of Arsenic and Stibium Bearing Gold Ores Bio-oxidation of arsenic and stibium bearing gold ores with acidithiobacillus ferrooxidans was studied. The preoxidation results show that the best bio-oxidation technical parameters are the initial pH in the range of 1.8 ~ 2.0, particle sizes under 0.074 mm, temperature in the range of 25¦C ~ 30¦C and rotating speed of the orbital incubator in 100 rpm ~ 160 rpm. The leaching results show that If the ore, of which contain 10.37 per cent arsenic and 36.81 per cent stibium, is not bio-oxidised, gold leaching is only about 41 per cent, after 8 days oxidised, the result is about 76.55 per cent, which improved about 35.62 points. The relationship between gold leaching and arsenic oxidation is direct proportion, furthermore, it needs only partly oxidise and higher gold leaching could be get, for example, gold leaching is over 90 per cent when asenic oxidation is 60 per cent. The results will provide theoretical and technological supports of bio-oxidation arsenopyrite for pretreating refractory gold ores.

Sep 13, 2010

By S. Borner Schweizer

An overview over SAM’s approach to assess corporate sustainability performance illustrates how sustainability challenges are linked to trends, assessment criteria and finally company performance. This process is exemplified with some general and industry specific criteria. Lastly, results of the Dow Jones Sustainability Assessment 2004 show a considerable gap between leading and average companies. Best practice examples demonstrate how lagging companies could improve their sustainability performance.

Jan 1, 2005

By Mike Adams

A comprehensive pre-feasibility study has been conducted by Companhia Vale do Rio Doce CVRD) for Niquel do Vermelho nickel laterite deposit. Within this study, five integrated flowsheet options were evaluated via batch and pilot campaigns at Lakefield Oretest, over an intensive six-month period from receipt of ore to final reporting. Key technical objectives set by the client included demonstrating the technical viability of the beneficiation of several ore types, processing through integrated pressure acid leach/mixed hydroxide precipitation (PALIMI-IP) and mixed sulfide precipitation (PALIMSP) circuits, and the treatment of barren liquors to meet stringent environmental requirements. Refining of the MHP was by ammonia re-leach and solvent extraction (SX) to produce LME-grade nickel cathodes, NiCO3, NiO and CoS. LME grade nickel and cobalt was also produced by oxidation of the MSP and hydrogen reduction on the leachate. The database and data acquisition system, along with web-based reporting, enabled rapid turnaround on both daily and more comprehensive run reports, making it possible for speedy and confident decisions on operating conditions of the complex flowsheets. The high value of developing such data is emphasized and discussed as pivotal in the successful progression of laterite projects through to sustainable commercial viability. Keywords: Flowsheet, CVRD, Nickel, Piloting, Pressure, Leach, Refining.

Jan 1, 2004

By William J. Neely

Augercast piles are formed by drilling a continuous-flight auger into the ground and, on reaching the required depth, sand-cement grout or concrete is pumped down the hollow stem as the auger is withdrawn. The sides of the hole are supported at all times by the soil-filled auger, eliminating the need for temporary casing or bentonite slurry. The augercast piling method is fast and economical; there is no vibration, very little noise and, if executed properly, no ground displacements during installation. The method is well suited to sands which are easy to drill and are readily transported up the auger. Relatively little attention has been given to augercast piles in the literature which might be part of the reason for the considerable variations in local practice, building code requirements and design methods. The purpose of this paper is to discuss some of the features of augercast pile installation that are known to influence both the structural and geotechnical capacity of the pile, to evaluate several empirical design methods and to look at some important aspects of quality control of augercast pile installation.

Jan 1, 1990

A Helix Pressure Gauge to Indicate roof bolt loads was designed, fabricated and field tested. The gauge indicated loads between 3,000 and 15,000 pounds with a ± ten per cent error. The coat of fabrication of the gauge was estimated to be $3.39 including an assumed overhead and profit per indicator for a series production of 5,000 unite. The unit can be read on a bolt to within ± 1,000 pounds load from a distance of twenty feet.

Jan 1, 1974

By B. Elevli

This paper deals with the selection of alternative accesses to a podiform chromite orebody in Turkey. The most important alternatives studied in a related project have been stated as a new vertical shaft and a ramp system. The comparison of these alternatives have been carried out on the basis of total investment costs, ore transport unit cost and net present value (NPV) of overall project for various depth. The results show that up to the depth of 700 m, the total investment cost and NPV favours the ramp access while unit ore transport cost make the shaft access preferable.

Jan 1, 2002

By Pat McLaughlin

Environmental constraints are pushing many operators to change from large rotary blastholes to the smaller diameter holes drilled with down-hole or top-hammer rigs. Productivity improvements over the years with these two drilling techniques has taken some of the bite out of the transition, while improved fragmentation and more uniform muck due to the tighter patterns can help offset increased explosives costs.

Jan 1, 1995

By A. Cecala, J. Noll, J. Hummer

The National Institute for Occupational Safety and Health has observed that many control rooms and operator compartments in the U.S. mining industry do not have filtration systems capable of maintaining low dust concentrations in these areas. In this study at a mineral processing plant, to reduce respirable dust concentrations in a control room that had no cleaning system for intake air, a filtration and pressurization system originally designed for enclosed cabs was modified and installed. This system was composed of two filtering units: one to filter outside air and one to filter and recirculate the air inside the control room. Eighty-seven percent of submicrometer particles were reduced by the system under static conditions. This means that greater than 87 percent of respirable dust particles should be reduced as the particle-size distribution of respirable dust particles is greater than that of submicrometer particles, and filtration systems usually are more efficient in capturing the larger particles. A positive pressure near 0.02 inches of water gauge was produced, which is an important component of an effective system and minimizes the entry of particles, such as dust, into the room. The intake airflow was around 118 cfm, greater than the airflow suggested by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) for acceptable indoor air quality. After one year, the loading of the filter caused the airflow to decrease to 80 cfm, which still produces acceptable indoor air quality. Due to the loading of the filters, the reduction efficiency for submicrometer particles under static conditions increased to 94 percent from 87 percent.

Jan 1, 2015

By Qiang Fu

ABSTRACT This paper aims to identify the main issues concerning top-coal loss and the optimum drawing interval of LTCC (Longwall Top-coal Caving) mining by underground tests and DEM (Distinct Element Method) modeling. By extracting a new roadway in the goaf of the mined LTCC Panel No.4318 in Wang Zhuang coal mine of Lu-an CMA (Coal Mining Administration), and underground observation of the distribution of loss coal and broken rock in different sections of the roadway, this paper analyses the composition and presents a 3-D distribution map of the loss coal in the exploration roadway. This study indicates that the DEM modeling of broken top-coal is reasonable and scientific as it can simulate the movement of broken coal and waste rocks and determine the optimum drawing interval of top coal.

Jan 1, 2002