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The development of an onboard contaminant diagnostic monitor to continuously measure contaminant level in a mining machine was advanced to a prototype stage in this contract. Several concepts were investigated and it was found that a static spool type sensor was the most reliable and accurate. Laboratory and field tests showed that an instrument based on this concept is capable of measuring contaminant levels and/or size distribution, depending on the configuration of the sensor. Moreover, this instrument can function on emulsions or homogeneous fluids. Current laboratory equipment can operate on homogeneous fluids only.

Jan 1, 1983

A model was developed to facilitate secondary tailgate support selection based on analysis of over 100 case studies, compiled from two different surveys of operating longwall coal mines in the United States. The ALPS (Analysis of Longwall Pillar Stability) program was used to determine adequacy of pillar design for the successful longwall case histories. A relationship was developed between the secondary support density necessary to maintain a stable tailgate entry during mining and the CMRR (Coal Mine Roof Rating). This relationship defines the lower bound of secondary support density currently used in longwall mines. The model used only successful tailgate case history data, with adequate ALPS SF according to the CMRR for each case. This model facilitates mine design by predicting secondary support density required for a tailgate entry depending on the ALPS SF and CMRR, which can result in significant economic benefits.

Jan 1, 1996

By M. Faraji

Inclusions formed in a high-carbon, manganese-silicon killed plain steel (Fe-0.77C wt%) were studied. Various techniques were used to characterise the inclusions, and the latter were classified according to their chemical composition, size and morphology. The main constituent elements entering the inclusions were Mn, S, Al, and oxygen. Alongside MnS and some Al2O3 inclusions many non-metallic inclusions appeared in complex forms, consisting of silicates, sulphides and oxides. Duplex oxy-sulphides, mainly MnS combined with Al2O3, or SiO2 were the most common complex multiphase inclusions in this steel. The nanoindentation technique was used to assess and rate different types of inclusions and data of the hardness and elastic modulus of individual inclusions at room temperature are presented.

Jan 1, 2010

By John D. Spencer

Clean energy production from coal, oil, and gas, and the development of these and other energy sources continued to be a major objective of the energy research program of the Bureau of Mines.3 In 1971 increased emphasis was placed on the production of fluid fuels and chemicals from coal. Advances were achieved in the development of the Synthane and Hydrane gasification processes for producing pipeline gas from coal (page 31), and progress was made in research on solid wastes utilization (page 2), and on liquid fuels production from coal (page 37); Coal mine safety, solid waste disposal and utilization, coal preparation and transport, and fundamental research on coal and related products also continued to be the subject of extensive research. Improved methods for extracting petroleum and natural gas without surface and subsurface pollution featured research on these vital fuel and energy sources. This research was highlighted by studies of the fracturing systems of reservoir rocks, including subsurface fracture mapping and new fracturing techniques to achieve optimum production of oil and gas (page 52). Of equal importance were projects on oil recovery by water or gas flooding (page 52), by steam injection (page 57), on the identification of oil spills (page 63), and on means to reduce vehicular exhaust emissions (page 66).

Jan 1, 1972

By R. S. Warfield

Several reconnaissance-type surface and drill core samples of Arctic Northwestern Alaska coals were taken during the summer field seasons of 1964 and 1966 for coking studies. Surface samples were taken from the Kokolik River and the Cape Beaufort areas; core samples were obtained from the Kukpowruk River and the Cape Beaufort areas. Only one Kokolik River surface sample possessed coking properties. This sample, representing an 11.6-ft coal seam, made coke approaching metallurgical quality when a 30-pct portion of selected blending coals was added. Four Kukpowruk River core samples, each representing the same 19-to 20-ft coal seam, were all of about the same coking quality. No differences of coke quality attributable to depth of permanently frozen overburden were found, but the data confirm previously reported information that the 19- to 20-ft coal bed is a potentially satisfactory base coking coal. In the Cape Beaufort area, a core sample with appreciable coking properties was taken at depth from a coalbed determined noncoking in a surface sample.

Jan 1, 1969

By S. Raghavan

An investigation of the possibility of improving the grinding characteristics of a gabbro ore containing copper and nickel sulfides via a thermal shock treatment technique has been carried out. The results obtained indicate that the breakage characteristics of the gabbro are particles can be significantly improved by preheating the are particles to a temperature around 400°C followed by rapid water quenching. For a given power input and feed size, the thermally treated material produces a product of much finer distribution than the untreated material. An assessment of the improvement in grindability has been made by calculating feed size selection functions for untreated and heat-treated materials.

Jan 1, 1981

By A. J. Potgieter, C. Hill, A. Humpel, D. S. Magudulela, V. Scholtz, A. Coetzee

Keywords: Pyrometallurgy, long steel products, coke, sinter, blast furnace, steel plant Located in Northern KwaZulu Natal, Mittal Steel South Africa Newcastle works produces roughly 1.8 million tons per annum, supplying long steel products, locally and overseas. The great extent of local raw material availability and low conversion cost ensures that Mittal Steel South Africa is among the lowest cost, high quality producers of steel. MSSA Newcastle works can be subdivided into two main sections: The iron making side, comprising the coke ovens, sinter plant and blast furnace, and the steel making side, comprising the basic oxygen furnace, ladle furnace, continuous casters, and the medium, rod, and bar mills.

Jan 1, 2006

By G Anderson, M Mativenga, C Stanton, M Larson

Arrium’s magnetite concentrator has recently completed a modification program to improve the process that has been in operation in Whyalla, South Australia for the previous seven years. The magnetite concentrate is pumped via pipeline to the coast and serves as pellet plant feed, eventually being turned into steel in the Whyalla blast furnace. With the addition of a new 3MW IsaMill at the concentrator, the plant has seen increased production from a reduced feed grade, enabling Arrium to treat ores previously stockpiled as waste. This paper will focus on the design work and commissioning of the fine grinding circuit along with the year of optimisation that followed, taking the IsaMill up to 350+ tph of throughput.CITATION:Larson, M, Anderson, G, Mativenga, M and Stanton, C, 2015. The Arrium IsaMill from design through commissioning and optimisation, in Proceedings MetPlant 2015, pp 110–119 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

Urban development to the south of Sydney is approaching areas of current and proposed coal mining. Already some structures and residential areas are affected by mining subsidence.Subsidence resulting from either conventional pillar extraction methods or longwall mining has been monitored for 15 years to enable the characteristics of the surface deformation to be determined.The vertical and horizontal displacements of survey stations on the surface are monitored and the results arc used to calculate subsidence, changes in slope of the surface, curvatures along the subsidence profile, and the ensile and compressive strains. These features are in turn related to the underground extraction to give a description of surface subsidence and the development of subsidence with time.Subsidence investigations have been carried out over all or part of the workings of six collieries in the Southern Coalfield.Two case histories illustrate the procedure in the investigation of subsidence phenomena. The first example is the study of the subsidence over a series of longwall panels in one seam and the second is a study of subsidence over pillar extraction in two seams one above the other. From the results of the investigations the effects of panel widths on subsidence are determined.This and other information assists mine planning in areas where surface movement and deformation are important considerations.

Jan 1, 1980

By M. Feely, W. G. O'Keefe, C. O'Reilly, M. P. Holdstock

A petrographic and microthermometric study of fluid inclusions in the Kentstown Granite, crosscutting quartz (VI) and calcite+quartz (V 2) veins in the granite and calcite+quartz (V 2) veins in the overlying sediments was performed on samples taken from the borehole. Comparisons of the type 1, type 2 and type 3 fluid inclusion populations recorded in the present study with those from other Irish Caledonian granites strongly suggest a similar fluid evolutionary history. Furthermore, the low-temperature CaC12-rich brines (type 5) of this study, which must be syn- to post-Lower Carboniferous in age, have correlatives both in Irish Caledonian granites and in the Lower Carboniferous base-metal deposits of the Irish midlands

Jun 19, 1905

By Madgwick J. C

Microaerobic biodegradation oflow-grade manganese dioxide slurry tailings was demonstrated in enrichment cultures treated with dilute molasses at 30°C and pH 5·8. Supplementary nitrogenous nutrients, yeast extract addition and pH adjustment were not required.Continuously stirred, air-limited reactors were superior to still intermittently agitated cultures, in that, at 5 per cent (w/v) MnOz tailings and 5 per cent (w/v) molasses, the yield of 0.12 g Mn++/g molasses, the rate ofleaching of 1·06 g Mn++/l/d and a recovery of Mn++ of 58 percent from MnOz were 2·8 times, 1·7 times and 1·9 times greater, respectively. The best compromise in yield (0·45 g Mn++/g molasses) and rate ofdissolution (0·73 gMn++/l/d) was at 1 per cent (w/v) molasses in a stirred reactor.Where leaching organisms were separated from sterile ore by a bacteria impermeable membrane leaching was shown to be some 20 per cent due to diffusible metabolites and 80 per cent due to a direct contact between the bacteria and the ore particle's surfaces.

Jan 1, 1986

This paper pays tribute to the pioneers in geomechanics, and addresses some of the most pressing issues of our time related to deep mining, and how to mitigate these issues. Solutions developed by our predecessors seem to have reached their limits as mines continue to go deeper. The International Society for Rock Mechanics (ISRM) guidelines for rock mass characterization for excavation design also require re-thinking to reflect current knowledge and experience. Thus, a whole new approach is urgently required to increase mine safety and productivity. The paper will draw on the challenges and experiences in medicine and science that have been overcome through genuine collaboration, advances in technology, and impressive funding, which can be adopted to provide solutions to contemporary geomechanics challenges for increased safety and productivity as mines continue to go deeper.

Jan 1, 2014

By John C. Machisak

THIS PUBLICATION presents injury experience and employment data for the nonmetal mining industry in the United States for 1960. Data for the mines and mills are presented separately, as shown in the list of tables. The Bureau of Mines is authorized to send questionnaires to the nonmetal mining industry for their voluntary submission of injury and employment data. As the information submitted contributes largely to the promotion of safety in the industry, special effort has been made to ma e these questionnaires as complete as possible.

Jan 1, 1963

By Donna L. Anderson

This U.S. Bureau of Mines report describes a system to determine the position and heading of a continuous mining machine during the maneuvers required at the face area of a mine. The system consists of commercially available angular position sensors and a computer interface developed and tested at the Bureau. The sensors employed are laser-based scanning devices that report the angular location of retroreflective targets within their 90° field-of-view. The targets are mounted on the continuous mining machine; the laser scanners are mounted on an external reference structure. The computer interface consists of a single-board computer-controller programmed to gather and process the angular position information, and to calculate the machine's position and heading relative to the reference structure. A sensor fusion algorithm will be incorporated into the computer interface programming to increase the accuracy and reliability of the system.

Jan 1, 1989

By Mark I. Copeland

This study was conducted by the Bureau of Mines to determine the effect of steel reheating practices in burning natural gas on the amount of silicon required to prevent the formation of copper on steels containing up to 1 wt-pct Cu. Formation of copper, which causes surface hot shortness, was readily prevented by as little as 0.3 wt-pct Si and by 2 vol-pct excess oxygen in the furnace atmosphere when reheating steels containing up to 0.8 wt-pct Cu. Up to 0.8 wt-pct Si content and careful control of reheating conditions were necessary for steels containing 1 wt-pct Cu. Best conditions for these steels were reheating to 2,200° F (1,205° C) in burning gases containing 2 vol-pct excess oxygen, and then to higher temperatures in gases of 6 vol-pct excess oxygen. Slag and mold wash were not detrimental on steels reheated for 8 hr by a soaking-pit-type furnace schedule, but they were problematical on steels heated for 2 hr by a pusher-type furnace schedule. The effect of silicon contents on scaling rates also was determined.

Jan 1, 1974

By F. E. Brantley

Research was undertaken by the Bureau of Mines to assess the technical feasibility of smelting cement-copper precipitate in an electric furnace to produce commercial-grade copper. The blister-grade copper produced in smelting was refined by gaseous oxidation and reduction methods to rive a product equal in quality to fire-refined copper. The cement copper used in the study was typical of the material produced in commercial operations. The sample product was received in a partially oxidized state and analyzed 77.5 percent Cu, 3.4 percent Fe, 0.8 percent Pb, 0.05 percent Ni, 0.6 percent Sn, and 0.9 percent S. Smelting tests were made on the precipitate using laboratory-size induction and electric-arc furnaces. Three types of furnace linings were tested during, the investigation: Carbon, including graphite; clay-graphite; and silicon carbide. Although all proved satisfactory, either carbon or graphite was preferred because of their superior refractory properties and low permeability to molten copper. Copper recoveries in the induction and arc smelting tests averaged 92 percent in commercial-grade metal assaying 99.8 percent copper. Refining the molten copper by oxidation and gaseous reduction or by chlorine lancing increased the purity to plus 99.9 percent.

Jan 1, 1961

By J. L. Schwendeman

This is the final report of work done under contract H0210060 for the U. S. Department of the Interior, Bureau of Mines. This program was to show the feasibility of using plastic liners containing sand and other fillers as a means of roof support in coal and other mines. This laboratory study was conducted in two phases, namely: Phase I, directed toward determining which state-of-the-art resin systems might have utility as a means of roof support in a coal mine, consisted of a canvass of resin manufacturers to learn which resins were available commercially that might have utility for this application. The resins submitted by the manufacturers were evaluated in a number of simple tests to define which of them would be most suitable for roof support use.

Jan 1, 1972

By Douglas W. Fuerstenau

A detailed experimental study of breakage kinetics in a batch rod mill indicates that while the system is inherently nonlinear, the feed disappearance kinetics for the finer sizes and the coarser sizes at high holdups is well represented by first-order behavior. The set of breakage distribution functions was found to be normalizable and independent of particle holdup in the mill. The size discretized initial breakage rate functions were found to be inversely proportional to particle holdup and almost directly proportional to particle size. A linearized grinding model that results from the first-order Taylor's series expansion of the breakage rate expression was found to give good simulations of the mill product size distributions without recourse to any parameter improvement routines. Material transport through rod mills was evaluated by investigating the effect of operating variables on the holdup and residence time distribution of particulate solids flowing through the mill. Identical experiments performed in a continuous ball mill helped delineate the fundamental differences in particulate transport through these two types of mills. Mechanistic interpretations of the observed transport phenomena are presented, and their implications in the context of tumbling mill analysis and design pointed out.

Jan 1, 1980

By N Merry, T Cocks

The mineral exploration industry is increasingly aware of the importance of the relationship between mineralogical data and geochemical assay results. However, until recently, the cost and time constraints of most techniques for analysing alteration mineralogy have precluded detailed alteration studies. These impediments have been reduced by the development of the Portable Infrared Mineral Analyser (PIMA), a field portable infrared spectrometer that allows rapid (in field) and cost effective analysis of alteration minerals including subtle variations in mineral crystallinity and composition.   A major application of this technology is in mapping mineralogical variations within hydrothermal alteration systems. Using actual case study examples this paper introduces two approaches to using the PIMA data: 1. for directly mapping alteration systems and using the PIMA data to provide vectors to mineralisation, and 2. for establishing empirical relationships between geochemical data and PIMA spectral data. These applications demonstrate that this technology can be an invaluable tool for targeting and mapping alteration and mineralisation.

Jan 1, 1995

In this paper, the scientific bases of creation of simulation modelling systems of excavator-truck-conveyor complex work are represented. During the simulation modelling process of big mining and transport systems work the strict and full account of an order and sequence of all operations of simulated process is carried out. Step-by-step fixing of mining and transport system elements condition - excavators in loading and unloading points, trucks, road section, unloading points in storage bin, crushers and conveyors is conducted. Work and idle time of system elements are considered. During modelling process the information characterising system work as a whole is collected. It allows us to establish qualitative and quantitative influence of each system element on the final results of its functioning and provides to estimate rationality of a particular organisation variant of mining and transport equipment interaction from technological positions. Simulation results are: economic and technological indicators of mining and transport complex functioning of the period for each subsystem, as well as on the road, the points of loading, unloading and reloading.

Dec 6, 2010