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By S. J. Rodgers

MSA Research Corporation, Division of Mine Safety Appliances Company, was awarded a contract to conduct a survey of past and present methods used to control respirable dust in noncoal mines and ore processing mills. The survey covered information reported in mining journals, and U.S. Bureau of Mines Circulars, dust inspection reports, on-site evaluation of dust control methods and systems, and contact with manufacturers of dust control equipment. Both surface and underground mining operations were visited. Fifty mines and 51 processing plants were included in the survey. Dust control methods for the following types of ores or mines were studied: [ ]

Jan 1, 1974

? Develop a six year capital budget for future emission controls at Western Springfield Power Plant that would provide long-term operating certainty

Jan 1, 2005

By Richard L. Sanford

This report summarizes the results of the development of a Directory of Computer Programs Applicable to U.S. Mining Practices and Problems. The Directory includes a sampling of computer usage in operating and manufacturing companies, consulting firms, computer companies, research organizations, universities, and various U.S. government agencies. References to computer applications throughout the mining industry are presented as well as comments on the availability of programs to interested organizations or individuals.

Jan 1, 1977

By Jason J. Crowder

Presentation Outline ? Introduction ? Costs of ground support and rehabilitation ? Why post-failure rock mass properties are necessary ? The Rock Mechanics Problem ? Present State of Modelling and Instrumentation in Mining ? Case Study Background ??Williams Mine ? Deriving Parameters for Modelling from Instrumentation ? Results from Case Study ??Back Analyses ? Discussion of Research Impact t Summary

May 1, 2006

By X. Goso

Laboratory-scale tests were conducted at Mintek for the production of titanium powder from particulate Kroll sponge by the hydrogenation-dehydrogenation (HDH) process. The aim of this work was to produce titanium powder for powder metallurgical consolidations. The work involved the production of titanium powder at optimized conditions, which included hydrogenation in a horizontal tube furnace at 600°C for 2 hours, milling using planetary and roller mills, and dehydrogenation in a vacuumed retort fitted in a muffle furnace running at 700°C for 36 hours. The titanium powder produced in this project matched the elemental specifications of commercially available titanium powder, except for high carbon content. Nevertheless, the powder has been tested further in mechanical alloying and has been found suitable for the production of powder metallurgical compacts. Keywords Powder metallurgy, titanium components, HDH process, ball milling.

Jan 1, 2011

By J. E. McGill

The junior and small-scale mining sectors in South Africa play an important role in the livelihoods of numerous communities. Mining presents an opportunity, in the post-1994 democratic era, for many individuals to obtain access to much required empowerment and socio-economic development. These sectors are, however, not without numerous characteristics that pose problems for operators, legislators, and other role-players. Mining is inherently risky, with operators experiencing frequent difficulties and challenges throughout the life of mine. Opportunity exists, and needs to be enhanced, for junior and small-scale prospects and operations to include technical risk assessment techniques in documentation presented in search for funding, and in optimizing monthly planning and longer-term functioning. The focus here is to explore how the risk management cycle may currently be applied to a mineral resource suitable for exploitation by the junior and small-scale mining sectors. No management process can create additional value in the ground, but various available mechanisms can go a long way to quantifying the inherent risk that exists, highlighting the need to manage the risks and hopefully allowing the entrepreneur access to the intrinsic opportunities of the emerging mining sector in South Africa.

Jan 1, 2006

By G. B. Dukes

Scaling of rockpasses was problematic at Tau Lekoa Mine prior to production commencing in 1991. High horizontal stress levels relative to the host rock mass strength have been instrumental in causing the observed scaling. Scaling has been more pronounced in the deeper rockpasses and these are monitored regularly. Rehabilitation of one of the reef passes and one of the waste passes was required in the period 1999 to 2001. This paper describes the extent of the problems experienced to date as well as the rehabilitation completed.

Jan 1, 2006

By Bernard Hertlein

¦ Drilled shafts resist scour seismic loads better than groups of driven piles ¦ Drilled shaft construction creates less noise and vibration than driving piles ¦ Drilled shafts permit direct observation of bearing stratum, and confirmation of location ¦ Drilled shafts are cost effective

Jan 1, 2001

By David A. Hill, James R. Wait

This report contains a summary of analytical research on electromagnetic methods of nondestructive testing of cylindrical conductors. The principal objective is to provide theoretical insight to the operation of electromagnetic sensing of the internal properties of wire ropes that are used extensively in mine hoists. An overall review of past work is also included.

By Claudio Olalla

This paper relates to the foundation of a steel structure located at the San Martin de la Vega (Madrid) amusement park. The structure has more than 100 supports with various loading conditions, including important horizontal and uplift forces. Additionally, the settlement tolerances are very strict. A massive gypsum formation with interbedded clay layers and random solution great voids at various levels constitute the soil. The foundation design has been conditioned large enough these difficulties (load conditions and soil problems). The piling machine used was powerful to drill through the soft rock (UCS up to 11Mpa). The integrity of each pile had to be guaranteed by continuous recording of drilling and concrete pouring parameters. In order to fulfil all those conditions, a STARSOL type-piling rig was used. More than 4500 meters of piles were performed. The diameters of the piles were 450 and 550-mm and their depths varies from 6 to 23 meters. All piles were reinforced over their full length.

Jan 1, 2002

Jan 1, 1967

By Walter Herd

For the past eight years, No. 2 mine of the Cumberland Railway & Coal Co., Springhill-a subsidiary of the Dominion Coal Co., Ltd.-has had an unenviable reputation for bumps. As the workings extended in certain directions under a greater cover, these bumps increased in severity and it became apparent some change in the system of extraction was necessary if the mine was to continue to operate. In September, 1924, following several fatalities resulting from bumps, the Mines Depart~ of Nova Scotia requested from the U. S. Bureau of Mines the services of George S. Rice, Chief Mining Engineer of the Bureau, to report on the conditions then prevalent in No. 2 mine, Springhill. °This request was promptly and courteously granted. Mr. Rice made a full investigation and a comprehensive and helpful report, which is embodied in the 1924 Annual Report of the Department of Public Works and Mines, Nova Scotia. Prior to 1925, the room-and-pillar method was employed, and in January of that year (there being a cessation of work from March to August due to labour troubles) longwall retreating on the west side, on a limited scale, and in a small section on the east side of the mine, was started. The major portion of the east side was not operated on this system till August, 1926, as there was developed a considerable area ready for pillar extraction between an arbitrary boundary and a point up to which bumps of any consequence had not been experienced. In ?the interval, development work for longwall retreating below the 5,900-foot level was vigorously pushed.

Jan 1, 1929

Study to develop a new and more cost effective equipment system, incorporating a winch-pulled dozer blade, for leveling spoil and performing reclamation of area strip mines.

Jan 1, 1975

This Bureau of Mines publication contains five papers pertaining to the effective grounding of mine power systems, as follows: Ground-check monitor types and safety characteristics; ground wire monitors for surface coal mines; ground bed design and measurement; electrical ground rod corrosion; and a continuous ground bed resistance monitor.

Jan 1, 1979

By Qing Bo

In this study, the cobalt oxide precursor was prepared in open-style reactor in the condition of high reactant concentration, and then the precursor was decomposed to obtain the cobalt oxides (Co3O4). The effects of some factors on the cobalt precipitation, the particle size and size distribution, and the micro-morphology were addressed. The factors studied include cobalt concentration, initial pH of solution, temperature and time for the reaction, the charge amount of urea, and the temperature for decomposition. It is determined that the precursor particle is in the chemical composition of Co2(OH)3Cl with fine crystalline. By calcinations under proper conditions, the mono-dispersed cobalt oxide particles were prepared with fine crystalline, about 2 µ m in particle size and regular shape in morphology.

Jan 1, 2006

By A B. Christie

Known epithermal deposits in the Coromandel region belong to the low-sulphidation type, represented by three subtypes: (1) andesite-hosted epithermal Au-Ag, (2) rhyolite-hosted epithermal Au-Ag, and (3) andesite-hosted polymetallic veins. Paleo-depths for a range ofdeposits are estimated using various features including: paleo-surface indicators (e.g. sinters), hydrostatic pressures estimated from homogenisation temperature measurements on fluid inclusions, and alteration mineralogy. Paleo-depth estimates to the base of the ore zone for the rhyolite-hosted Coromandel deposits are in the range 200 to 500 m. Andesite-hosted Au-Ag deposits have more variable paleo-depths, and are deeper (up to 950 m) in those deposits with base metals at depth. The majority of Coromandel Au-Ag deposits have limited depth extents (<200 m) of economic grade mineralisation, although Waihi and Karangahake are notable exceptions with depth extents of 575 m and 700 m respectively. Limited depth extents of economic ore are a feature of epithermal systems worldwide and are commonly attributed to gold deposition from boiling fluids. Under hydrostatic conditions in epithermal/geothermal systems, boiling in an up-flowing hydrothermal fluid is controlled by the boiling point for depth (BPD) curve. From fluid inclusion studies of many low-sulphidation epithermal systems, deposition of electrum in economic concentrations appears to be confined to a temperature window of 260 to 180¦C. This means that for dilute, gas-poor fluids that follow the BPD curve, gold deposition is limited to a vertical depth zone of about 400 m, with its upper boundary at about 100 m below the ground surface. The greater depth extent at Waihi and Karangahake, can be explained by mixing of/a deep, hot (300¦C) fluid with cooler (c. 200¦C) heated ground waters. This has the effect of lowering the 260¦C isotherm by up to 300 m, thereby increasing the depth range of economic grade gold deposition within the 260 to 180¦Cwindow of electrum deposition.

Jan 1, 2000

By Louis R. Iverson

Analysis of seed numbers present in topsoils (a grazed area, an ungrazed area, and two stockpiles) indicated that seeds of the most prevalent colonizers (e.g., Kochia scoparla, Setaria virdis, and Salsolo collins) were not present in the topsoil upon respreading but rather appeared by immigration from the surrounding areas. The grazed site had a seed density of over 7,700 seeds m-2 (of which 43% were from weedy species) and the ungrazed site had 3,900 seeds m-2 (of which 7% were weeds); the stockpiled topsoils had very low seed densities (255 and 520 seeds m-2). Seed densities and diversity decreased with depth on both the grazed and ungrazed sites; this was especially true on the grazed site where 94% of the seeds were found in the surface 7.5 cm. Several species were present in the seed bank (e.g., Hedeoma hispida, Artemesia ludoviciana, A. frigida, and A, abslnthlum) which were also found on the three and four year old mined sites in the aboveground vegetation survey. Seeds from these species may germinate after several years of dormancy, thereby starting populations on mined sites and enhancing plant diversity. Seed bank analysis was also undertaken on mined sites ranging in age of 2 to 6 years (plus an unmined site). Mined site seed densities ranged from 1630 to 3980 seeds m-2, with the four year old site having the greatest density (largely because of high Melilotus spp. populations); unmined site and stockpiled topsoil sample had lower seed densities. A significant positive correlation between total viable seed content and soil-water saturation percentage indicated that soil texture may influence seed viability/ dormancy (the. finer the material, the higher the seed population). As with the previous part of this study (and other studies), there was a poor correlation between the aboveground flora and the belowground seed composition.

Jan 1, 1982

By A. Boominathan

The behaviour of single piles under lateral dynamic loading is very critical and the study is still a current field of research since 1950's. Though many methods have been developed analytically to estimate the dynamic lateral stiffness, very limited dynamic testing on full scale piles were carried out to study the response of piles under lateral dynamic loading. Hence, field lateral dynamic vibration tests are conducted on driven precast concrete square pile of 400mm size and driven cast in-situ concrete piles of 400mm and 500 mm diameter at a petrochemical complexes site at Haldia (India). The results of steady state and free vibrations tests are discussed herein and compared with the response of the piles estimated from PILAY.

Jan 1, 2002

By Shail J. Butani

In 1986 the Bureau of Mines conducted a probability sample survey, Mining Industry Population Survey, to measure such employee characteristics as occupation; principal equipment operated; work location at the mine; present job, present company, and total mining experience; job-related training during the last 2 years; age; sex; race; and education. The population estimates are necessary to properly analyze the Mine Safety and Health Administration (MSHA) injury (includes illness and fatality data) statistics; that is, to compare and contrast injury rates for various subpopulations in order to identify those groups that are exhibiting higher than average injury rates. This report uses the survey's results to characterize the U.S. sand and gravel mining workforce from March through September 1986. Similar reports have been prepared for the metallic, stone, and nonmetallic mining industries, as well as for the entire metal and nonmetal mining (includes metallic, stone, sand and gravel, and nonmetallic industries) sector and the coal mining sector.

Jan 1, 1988

By D. Peatfield

The design and operation of coal preparation plants are governed by the inherent quality of the raw coal to be processed, market specifications and the saleable tonnage requirements. Topography influences the layout of the plant but does not affect the process design. The coal market comprises many sectors, each having specific requirements with respect to both size and quality. In turn, these have led to different levels of preparation and the development of specific types of coal preparation plant design. Developments in processing techniques and processing equipment have also influenced the design and now give the preparation engineer numerous permutations in process and equipment selection. This paper gives an overview of the coal industry in general and summarizes some of the developments in the design of plants and technical developments in the areas of dense medium processing, fine coal treatment and equipment design.

Jan 1, 2003