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By Michael McVay

The use of augered cast-in-place piles has seen tremendous growth under commerical structures in the past twenty years. Problems with vibration, soil densification and/or heave associated with driven piles do not occur with properly installed augered piles. Augered cast-in-place piles were originally constructed (1950s) with diameters of .31 m (12 in.) and lengths up to 6.1 m (20 ft); however with the advent of better drilling equipment, diameters varying from .41m(16 in.)to .61 m (24 in.) and typical depths ranging from 18.3 m (60 ft) to 24.4 m (80 ft) are achievable. Reinforcement may vary from a single high strength rebar (Grade 60) at the top of the pile to a continuous steel cage depending on loading (compression, tension-uplift, and lateral). Typical axial design loads (compression) for a single augered cast-in-place pile are in the 445 kN (50 tons) to 890 kN (100 tons) range.

Jan 1, 1997

By D. J. Parker

On Thursday, March 18, 1937, the country was shocked by news of a terrific explosion at the New London, Tex., school, which caused the death of 280 pupils avid 14 teachers. The explosion occurred at about 3:05 p.m. in the largest of the 11 school buildings on the campus. Fire 1 shows this building, marked "Main high school building", with respect to other buildings, pipe lines, oil wells, and gas lines or the property.

Jan 1, 1937

By Pengfu Tan

Xstrata Copper at Mount Isa in Australia has operated one copper Isasmelt furnace and four P-S converters. The phenomena of foaming occur in above 10% of converter operations. A thermodynamic model of copper P-S converter and a viscosity model of converter slag have been developed to simulate the slag blow and copper blow. The model predicts the chemistry and viscosity of copper skims during copper blow. The effects of oxygen potential, charge of dirty materials, slag carry-over, under-blowing, over-blowing, and temperature on the foaming and viscosity of copper skims have been discussed. Some improvements of the industrial operations have been presented.

Jan 1, 2006

A drive, 3,500 ft long, was planned to explore mineralization exposed by diamond drilling. A rate of advance of 150 ft per fortnight, approximately double previous Broken Hill rates, was required. Subsequent to the completion of this drive its extension for a further 6,200 ft was planned to provide a main haulage way along which ore could be transported from a newly acquired lease back to the main hoisting shaft, a total distance of 13,500 ft.This paper describes the working conditions, relationships, manning and costs, and gives details of the cycle and equipment used to achieve rates up to 170 ft per fortnight.OBJECTIVEDiamond drilling from the 1,000 ft level at the Delprat Shaft section had indicated that the zone of mineralization, about 150 ft wide, which had been explored on the 1,000 ft level for a length of 2,600 ft, continued downwards with a westerly dip. The drilling results showed that within this wide zone there were arrower lenses of mineralization of possibly payable grade (see composite plan, Fig. 1).Diamond drill holes of 2,000 ft and over, particularly through heavily sheared areas of sericite schist, had been found to be costly, slow, and inadequate in testing the potential and trends of these smaller concentrations of mineralization.It was therefore decided that an exploratory drive should be advanced from the northern limit of the 1,480 ft level into the western mineralization, and that from this drive diamond drill holes should be drilled at dose intervals to outline the ore.The 1,480 ft level was chosen for the following reasons.1. It had the greatest northerly reach of the accessible levels at No. 7 Shaft section below the 1,000 ft horizon and therefore would enable the test to be made most quickly.

Jan 1, 1965

Minerals are vital to any industrialized civilization. Annually, the United States uses more than 4 billion tons of new mineral materials, or about 40,000 pounds per person-about half being mineral fuels and the other half being metals and nonmetallics. Stable and economic domestic mining, mineral, metal, and mineral reclamation industries are essential to the economy. The value of United States energy and processed materials of mineral origin exceeds $200 billion annually. Although a number of minerals are imported, especially some designated as "strategic and critical," most U.S. mineral supplies are derived from the domestic mines and processing facilities that you will be seeing, reading about, and visiting as you use this visitor guide. We hope you enjoy your experiences. This pamphlet, a guide to mining and mineral operations that may be observed or visited and some other points of interest relating to minerals, is intended to aid tourists and students who are interested in mining. Some may wish to study our Nation's romantic past; others may plan to enter the minerals industry as a career; still others may have a primary interest in conservation practices. The pamphlet is also intended to aid State and local officials, Chambers of Commerce, and mining firms in answering some of the many questions of tourists and students.

Jan 1, 1977

By M. R. Dion, K. Frenette, R. K. Jonas, S. Simard, F. Robichaud

"In 2011, a site study indicated that the application of Honeywell’s Multivariable Predictive Control Technology (MPC) to the Goldex processing facility would provide significant opportunities for improvement. Grinding MPC was implemented in the SAG Mill in June 2015. This pilot application, called Phase 1, featured one of the first Multivariable Predictive Controllers to be installed in a Canadian mineral processing plant. Since the implementation of MPC, gold recovery from the gravity circuit has increased. MPC contributed to a decrease in flotation feed particle size (120 to 112 µm) and an increase in the SAG feed tonnage (8.5% increase). MPC also increased and stabilized the % solids of the SAG feed, which can have an impact on cost reduction (mechanical maintenance). Additionally, MPC increased productivity, providing grinding operators with more time to perform other tasks. Further anticipated benefits include the standardization of the grinding circuit operation from one team to the next, thereby minimizing circuit disturbances resulting from different operating philosophies. This paper will discuss the advanced control project development and justification, the technology and rapid implementation process, the performance results and the benefits obtained.IntroductionGoldex is an underground mine located near Val-d’Or that is owned and operated by Agnico Eagle Mines Limited (AEM). Between 2008 and 2011, mining focused on the Goldex Extension Zone (GEZ). In 2011, the project was halted due to geotechnical problems; operations ceased until late 2013. Goldex operations resumed in September 2013 with the M and E zones, for which there were 0.7M gold ounces of proven and probable reserves, 2.1M ounces of measured and indicated resources and 1.2M ounces of inferred resources, totalizing 4M ounces. Life expectancy was extended until 2024."

Jan 1, 2017

By Frederick W. Slack

This paper will discuss the inherent value engineering associated with the design and construction of approximately 184,000 SF of anchored tieback wall, installed as part of the widening and drainage improvements for KY9 in Campbell County, Kentucky. The total project is 2.2 miles in length. The anchored walls, excavation grading and drainage total to a complete project cost of $28.4 million. This is one of the largest design-build projects undertaken by the Commonwealth of Kentucky. It also features another first for the Transportation Cabinet - the general contractor is responsible for quality control/quality assurance. The project is located just south of Cincinnati, OH and is situated along the east bank of the Licking River. The slopes along this stretch of the river have had a long history of movement and instability. The Kentucky Transportation Cabinet advertised the anchored wall portion of this project to be designed and constructed by pre-approved specialty contractors. The Transportation Cabinet provided the basic design parameters to each specialty contractor. Aspects to be discussed include the site and project history, previous attempts at slope stabilization along existing KY9, the technical proposal and bidding process, and the actual design and construction.

Jan 1, 2003

By Daniel N. Adams

The University Link project extends Seattle?s light rail from downtown to University of Washington (UW). It includes 5.0 kilometers (3.15 miles) of twin-bored, 6.4 meters (21 feet) excavated diameter tunnels, and two cut-and-cover stations. The Capitol Hill Station (CHS) requires an excavation 170.7 meters (560 feet) long, 22.6 meters (74 feet) wide, and 22.9 meters (75 feet) deep. The University of Washington Station (UWS) requires an excavation of about 238.4 meters (782 feet) long, 21.3 meters (70 feet) wide, and 33.5 meters (110 feet) deep. The project is within the glacially diverse soils of the Puget Sound region, below groundwater. This paper highlights major station and tunnel design elements, including the approach to support of excavation at both station boxes, and the site staging requirements.

Jan 1, 2008

By A. E. Raddatz

The Bureau of Mines is investigating methods for recovering tungsten from domestic resources. A calcine-quench-leach (CQL) technique was developed for the extraction of tungsten from the Golconda, Nev., hot springs ores. The deposit contains disseminated tungsten that cannot be beneficiated by conventional techniques and must be treated by hydro-metallurgical methods. The CQL procedure consists of calcining the ore at 900° C for 3 hours, quenching in a solution containing 1.5 parts of Na2C03 and 1.5 parts of NaOH per part of WO3 in the ore and at a solution-to-ore ratio of 3 to 1, leaching at 200° C and at 250 psig for 3 hours, and filtering and washing the residue. A series of closed-circuit batch tests showed that 92 pct of the tungsten was extracted from a sample containing 2.32 wt-pct W03. The pregnant solution contained 11 g/l W03.

Jan 1, 1982

THE Wonthaggi coal-field lies south easterly from Melbourne at a distance by rail of 86 miles, on the flats of the Powlett River, immediately to the south of the deep-cut valleys and steep intervening ridges in the Jurassic rocks of the Bass Range and itsfoot-hills. The coal-bearing area is covered with a thin layer of late Tertiary and Recent deposits, which serve to mask the true character of the underlying coal-bearing rocks and effectually prevent the appearance of any coal outcrop. Two or three bores sunk prior to 1890 had shown the locality to be really a potential coal-bearing one. Only one additional bore was sunk in the State Coal Mine area until 1908, when energetic boring was resumed, with the result that in November, 1909, when an acute shortage of black coal in Victoria resulted from the prolonged strike on the New South Wales coal-fields, coal-seams had been located at Wonthaggi offering sufficient inducement to start an...

Jan 1, 1918

When xanthates or dithiophosphates are used as collectors in sulphide ore flotation, adsorbed species may be identified by gas chromatography of the volatile products formed during low temperature pyrolysis. For collector additions ,as low as 20 g/tonne of ore, pyrolysis of the flotation products usually gives' an olefin directly related to the particular xanthate or Aerofloat reagent used. The method is able to provide valuable qualitative and quantitative data relating to the extent of collector adsorption and the resulting changes in the hydrophilic or hydrophobic nature of the mineral surface.

Jan 1, 1974

By Budiselic C, Hefter G

The uptake of gold by activated carbon from acid chloride solutions involves the reduction of gold(IIl) to metallic gold. Deposition occurs only on the surface of the carbon at localized active sites at first, and subsequently at less active areas. The rate of uptake depends on the surface area of activated carbon, which confirms results from a recently published study (de Siegel and Soto, 1984). Increased rates of uptake were observed at higher temperatures and lower chloride concentrations due to the decreased stability of AuCI4-, the major gold(IIl) species present. Recoveries of gold approached 100 per cent for a contact time of 60 minutes at 20°C in a well stirred solution initially 5 ppm in gold(III) and containing 0.5 per cent w/v coconut-shell carbon. The presence of 0.25 Mnitric acid or 100 ppm iron(IIl) had no detectable effect on either rate or efficiency of gold uptake.

Jan 1, 1985

By R. V. Higgins, G. B. Shea

"FOREWORDIn the second year of World War II, the petroleum industry in California was taxed to near capacity to satisfy the expanded war demand for petroleum products, particularly fuel oil. With discoveries of crude oil in California declining and known reserves being depleted rapidly, conditions appeared to warrant study of the possibilities of utilizing the outcropping bituminous sandstone deposits in California for obtaining new sources of oil if the war should he prolonged. At conferences in Washington, D. C., with members of the Petroleum Administration for War and the Geological Survey, Bureau of Mines engineers emphasized the importance of determining the extent of those outcropping deposits of oil-impregnated rocks and of developing a practical process for commercial recovery of the contained bitumen to assure, if necessary, a supplementary supply of fuels. The desirability of such a study was recognized, and in July 1943 the Petroleum Field Office of the Bureau of Mines at San Francisco, Calif., in cooperation with the Geological Survey and the Petroleum Administration for War, initiated a study of the bituminouss sandstone problem. It was agreed that all mapping and geological work in connection with the study would be done by the Geological Survey, all engineering studies in developing a process for extracting the oil would be carried out, by the Bureau of Mines, and that the Petroleum Administration for War would aid in final adoption of the results in the field if circumstances warranted such action.Deposits of bituminous sandstones in California occur principally in the immediate region of the Coast Range mountains, notably at Pt. Arena, in Mendocino County, about 110 miles north of San Francisco; near Santa Cruz, in Santa Cruz County; in the Edna area in San Luis Obispo County; in the Sisquoc area in Santa Barbara County; and in the Ojai and Santa Clara Valleys in Ventura County. 4/ In addition oil-bearing sands outcrop near McKittrick and Maricopa, in western Kern County, and along the east edge of the Kern River oil field. Among the several prominent deposits of these source materials, those occurring near the cities of Santa Cruz and San Luis Obispo, and the town of Sisquoc are the largess."

Oct 1, 1948

By F. Grant

"General *The mining experiences of the coal mining industry in Western Canada have been extremely varied, with the mining companies having to adjust their operations or fail due to the harsh economy of the country in the first part of the century. The bituminous or mountain mines had the railways as main consumers with, at times, optimism that potential steel producers would require metallurgical coal. The prairie and foothills mines mainly provided household fuels, with the fine coal sold to local thermal power plants at discounted prices. In practically all cases fuel competition was very keen, and the less successful mines ceased operations in short-time spans. Knowledge of the parameters that governed the success or failures of the past coal operations should be of value to the present and future mining companies. The initial coal mines were small and were started to supply local demand. These mines had little in the way of capital machinery, engineering, or transportation equipment; therefore the mining methods and mine plans were very simple. The first industrial-sized mines imported most of their management and mining methods from other mining areas, mainly Great Britain. It took time to change the bias of management and mining methods to the requirements of strata characteristics, with rapid closure to those mines that were slow to adapt working methods. The main markets for coal were for household fuel, thermal power plants and railways, with very few other industrial markets developed. The economy of the period was harsh and cyclic and the coal mines were affected more than most industries by these boom and bust periods. It led to the survival of the fittest or the most efficient. Due to the economy, mechanization was introduced to the mines very slowly, with the inability to sell coal fines at a profit being another reason for the delay. Manual labour with hand tools was the main means of production. The work was heavy and arduous, and the pay was based on contract coal tonnage; therefore both men and management paid close attention to details so that nonessential work could be eliminated. Mine openings were dimensioned so that coal could be loaded easily by hand and support requirements were kept to the minimum. Transporting and handling the timber supports required heavy labour; thus the most efficient dimensions were chosen to suit the strata. On the other hand, during the main production seasons the mines tried to make the strata stress work for them so that the pressure was kept on the coal face to keep the coal loose while the strata, a short distance back, was induced to cave to minimize the abutment stresses. This caused mining to be an art, using skills developed by experience with the strata. This led to the development of efficient mine layouts with the openings dimensioned to the strength of the strata and the type of support available. The lack of capital and mechanization, and the manual labour, induced the mines to correlate their service and haulage systems with their mining methods. This caused many innovations that proved very practical."

Jan 1, 1985

By F. Albayrak

This report is a study of the impact of Federal laws and regulations on the domestic supply of metallic and nonmetallic minerals. The study was confined to pertinent environmental legislation and the recently enacted Federal Mine Safety and Health Act of 1977. Emphasized were the legal requirements placed on individual selected mineral industries, and the economic impact of these requirements. A certain amount of attention was also directed to the particular environmental and health and safety problems generated by selected mineral industries. The study also pinpointed a list of major problem areas having significant impact on the domestic mineral supply.

Jan 1, 1978

By L. A. Matthews

The embrittlement of the Ti-6Al-4V alloy by hydrogen dosing at elevated temperature has been investigated. Metal coupons were subjected to isothermal treatments in a partial hydrogen atmosphere in the temperature range from 650ºC?950ºC and the degree of embrittlement after treatment was determined by drop-weight impact testing. Embrittlement was found to be inversely related to reaction temperature as a result of the combined effects of greater hydrogen absorption and titanium hydride precipitation at the lower isothermal temperatures. Keywords Titanium, hydrogen embrittlement, impact energy

Jan 1, 2011

A major highlight of Fiscal Year 1993 is the completion of a new research facility dedicated to the advancement of robotics research and development. This new facility brings to the U.S. Bureau of Mines one of the largest and most unique facilities of its kind in the world. Located at the Bureau's Pittsburgh Research Center, the facility consolidates under one roof, all of the resource requirements of a first class automation and robotics research program. The Mining Robotics Development Center (MRDC) is the result of a major renovation of a large under-utilized warehouse-type structure and brings together the laboratories and offices previously housed in five separate buildings scattered throughout the Pittsburgh Research Center's 238-acre site. This new facility will support the computer-assisted mining research program, a high priority, multi-million dollar program that is expected to have a high impact on the health and safety of miners and coal productivity.

Jan 1, 1993

By R. D. Stewart

Paper presented at the conference: Risk assessment in the extractive industries, held in Exeter, UK, 23-24 March 1994, and first published London: IMM, 1994, preprint volume, 18pp., 5 refs. A seismic risk assessment method has been developed for application to rockburst prone deep-level mining sites which have sufficient seismic coverage. The technique utilises several seismic hazard parameters simultaneously and assesses the seismic risk on a daily basis according to the individual levels of these parameters. Critical levels are determined from investigation of the long-term behaviour of the parameters in relation to recorded potentially damaging seismic events. The method has been applied to a data set comprising 15 months' worth of seismic data, with encouraging results

Aug 1, 1995

By António Fiúza, Anthony Danko, Patrícia Leitão, Aurora Futuro, Cristina Vila, Lurdes Dinis

The average global recovery rates for processing scheelite ores by physical methods are normally in the range 50 to 70%, and it is problematic to attain a minimum grade of 60% WO3 in the concentrates without penalizing further this yield. Direct hydrometallurgical processing of low-grade concentrates or medium- to high-grade ores may become an interesting global economic alternative as it allows increasing the recovery rate, avoiding major penalizations due to the grade of the concentrate and increasing the added value of the final product. Leaching of scheelite by sodium carbonate presents several advantages such as its selectivity regarding the dissolution of troubling metals like iron and aluminium, allowing for a simple and flexible process diagram. However, it has the disadvantage that it is performed at high temperature and pressure with a high consumption of reagents. The feasibility of leaching is appraised by the extraction yield and selectivity, but also by the operating cost. Considering these aspects, a relevant objective of the research was to transform alkaline pressure leaching into a feasible processing alternative directly applicable to both medium- and high-grade ores and simultaneously to low- and high-grade concentrates produced by physical methods. The research used ore samples and low-grade concentrates from a typical skarn orebody as well as high-grade concentrates from a chalcopyrite-scheelite orebody. Different operating conditions were tested. Temperature, pressure and reagent concentration showed to be fundamental, but not exclusive, in determining the leaching behaviour. The operating conditions are milder than the ones generally proposed in the literature or currently in use in industry, but with higher carbonate consumptions. The research was oriented towards potential industrial implementation allowing for the application of optimization methods and straight scale-up to pilot-plan design and project.

By W. Burger

In underground mines worldwide, a large number of short and small diameter slot holes need to be excavated. Herrenknecht has developed and built a new boxholeboring machine based on the well-proven Microtunnellingpipe jacking technology. The innovative Boxhole Boring Machine significantly increases work safety and requires only minimal drift dimensions. The high and consistent production rates that can be achieved result in enormous time savings compared to conventional drill and blast excavations. GENERAL ASPECTS In gold, copper and ore mines ventilation shafts are required to prepare block caving operations, to discharge ore onto the transportation level and to provide evacuation shafts. A high level of occupational safety and efficiency is the main objective when drilling vertical or inclined shafts. The faster and more safely shafts can be constructed, the earlier the actual production in the mine can start or be continued. Mechanized or conventional methods (drill&blast) that have been used to date only partially meet the required safety standards and fail to provide the requested production rates.

Jan 1, 2012