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By J. R. Lucas, R. L. Frantz

Mine sealing programs for the alleviation of acid mine drainage were begun by the Federal Government in the '30's. As part of an acid mine research project to The Ohio State University, a field test was undertaken to determine the effectiveness of mine seals for reducing mine acid. Details of the tests made at the McDaniels mine show the feasibility of air-sealing and flooding an acid-producing drift coal mine. Work by the University continues. The Federal Government undertook in the early thirties an extensive mine sealing program for the alleviation of acid mine drainage. In the states of West Virginia, Ohio, and Pennsylvania many general summaries have been made on this program but no critical evaluation with supporting data has been found on the effectiveness of mine seals for reducing mine acid. Because of this it was decided to undertake a field testing program as part of an acid mine research project of the Engineering Experiment Station, The Ohio State University. The objective of this phase of the project was to develop and install a field research laboratory for acid mine drainage studies. Specifications for such a mine laboratory were developed and resulted from the following considerations: 1) Size and preservation—the test mine shou1d be of limited size to permit frequent and detailed examinations; it should be in a reasonably sound condition to permit safe entry. 2) Isolation—the mine should be physically separated from all other mines. 3) Openings—a minimum number would be desirable to reduce the sealing problem. 4) Structure—the mine especially near the openings should be structurally sound. 5) Acid production—the mine should be producing significant quantities of acid. After considerable searching, the McDaniels mine was selected in the Hocking coal field in Vinton County just above Lake Hope State Park in southeastern Ohio. The small drift mine in the middle Kittaning coal consisted of two small rooms with one mine opening about 6 ft above a seasonal stream bed. Before it was finally decided to seal the mine, a short study was made of the acid drainage over several months. Fig. 1 shows a plot of acidity (milligrams per liter), flow (gallons per minute), and acid production (pounds per day) vs time over the sampling period. Because the coal was overlain with a porous sandstone, the mine drainage was consistent the year around even though the mine was

Jan 1, 1961

By Frank A. Peters

This evaluation of the sulfurous acid process for the production of metallurgical-grade alumina is the first of a series concerning various known methods of extracting alumina from low-grade aluminous materials and was undertaken to permit comparison with other processes. In the process with which this Bureau of Mines report is concerned, calcined clay is leached under pressure with 20 percent sulfurous acid and then filtered to remove a siliceous residue. The aluminum sulfite remaining in the filtrate is precipitated as a monobasic sulfite which, together with iron sulfite, is then decomposed under pressure to form a crude alumina hydrate and iron oxide. This intermediate product is purified in a modified Bayer process to yield alumina suitable for electrolytic reduction to aluminum. A study estimate (16)3 is used for these evaluations. The capital cost, not including land, is estimated at $95,701,600 on a Marshall and Stevens index basis of 240.0 for a plant producing 1,000 tons a day of alumina or 350,000 tons a year. The annual operating cost for this size plant is estimated at $22,831,100 or $65.23 per ton of alumina using clay at $1 per ton. Depreciation and local taxes are included in the estimate, but profit and Federal taxes are not considered.

Jan 1, 1962

By L. D. van Dyk

The extraction of iron and lead from their oxides with a volatile organic ligand such as acetylacetone in the gas phase offers potential advantages of lower energy consumption, recycling of the extractant, recovery of pure metals, and a reduced environmental impact compared with conventional extraction processes. The influence of reaction temperature, ligand flow rate, and metal oxide levels on the extraction and rates of reaction of iron and lead from single metal oxide (synthetic haematite (Fe2O3) and synthetic massicot (PbO)) systems in a fluidized bed was studied. It was found that at the investigated acetylacetone flow rates, the influence of mass transfer was limited, but that the reaction suffered from reactant starvation. When the metal load increased the effect of starvation on the rate of reaction also increased. The reaction kinetics increased with an increase in temperature for both systems. At low metal oxide concentrations more that 80 per cent of the iron and lead could be extracted from their respective metal oxides after only four hours.

Jan 1, 2012

By E. A. van Wyk, M. R. de Villiers

"Mining companies strive to increase and maintain production, while simultaneously remaining competitive in the global economy. Furthermore, they must ensure workers’ safety and maintain good safety records. The use of virtual reality (VR) facilitates the development of tools and systems for various purposes that can improve knowledge and understanding of the work environment. VR is a rapidly growing technology that uses the ever-increasing power of computing to simulate real-world and imaginary environments and situations with a high degree of realism and interaction. The availability of 3D modelling tools and simulation programming engines that work effectively with a mid-range desktop PC and standard 3D graphics card, make VR technology viable and attractive for mainstream training applications. The design, development, and implementation of interactive VR training systems is proposed as an innovative approach to augment safety training. However, in order to assess the impact of such VR training systems it is of particular importance to determine the effectiveness of the design of such systems. This article proposes an evaluation framework for this vital purpose. This framework comprises criteria to assess VR training systems, specifically relating to usability, instructional design, VR systems design, and mining industry context-specific aspects. Although the framework was developed as an evaluation tool to assess effectiveness of the design of such systems, it can equally well be used as a set of design principles to inform the design of VR training systems for mining. IntroductionMining in South Africa has been the main driving force behind the history and development of Africa’s richest and most advanced economy (Coka, 2012). The South African mining industry is frequently criticised for its poor safety record and high fatality rate (Stoddard and Skweyiya, 2016). Inadequate or insufficient training is often cited as a root cause of accidents (Van Wyk and De Villiers, 2009; Tichon and Burgess-Limerick, 2011). Virtual reality (VR) is a rapidly growing technology that utilizes the ever-increasing power of computing to simulate real-world and imaginary environments and situations with a high degree of realism and interaction (Webber-Youngman and Van Wyk, 2013). VR is currently being used or investigated as a training solution in a variety of industries. VR technology has developed rapidly and costs have fallen to levels where it can now be considered for mainstream training applications. The availability of 3D modelling tools and simulation programming engines that work effectively with a mid-range desktop PC and a standard 3D graphics card, make VR even more attractive to mine training centres (Van Wyk and De Villiers, 2009)."

May 1, 2019

By Robert M. Doerr

The research objective was to determine the effect of aluminum alloy additions on the oxidation behavior of cobalt-nickel alloys. Thirty high-purity alloys were reacted with 02 at 0.5 atm at 1,351°, 1,389°, and 1,429° K in a volumetric apparatus for about 300 min. The alloy compositions consisted of Co-Ni master alloys (0, 22, 50, 70, 91, and 100 wt pct Ni) with aluminum additions of about 0, 1, 2, 4, and 8 wt pet. Large early deviations from, or changes in, the parabolic rate constant were encountered, but in most cases, the reaction rate declined approximately in accordance with the parabolic rate law. A sharp peak in the parabolic oxidation rate constant was observed for specimens containing a to 22 percent nickel and 1 to 2 percent aluminum at 1,351° K, and the rate constants for these compositions were lower at the higher temperatures. Specimens containing 8 percent aluminum reacted far more slowly than did any of the others.

Jan 1, 1971

Previous published papers by Fraser (1), Hey (2), and Stillwell (3), have given respectively, details of:-1. The practice in the pilot plant operated at Zeehan for the treatment of ores from the Rosebery field.2. The design, based largely on the experience gained at Zeehan, of the concentrator built at Rosebery.3. The nature of the orebodies of the zinc-lead lode at Rosebery.Changes and developments, at the Rosebery concentrator, since operations commenced, are now described with particular reference to recent practice.Three concentrates are produced, viz.: a copper, a lead, and a zinc concentrate. The current flow-sheet is shown in Fig. 1. Typical concentrate assays are...THE OREThe ore treated is derived from the Rosebery and Hercules Mines and is, milled in the ratio of, approximately, two parts of the former to one of the latter. The ores from the two mines may be considered as being similar in general character, although the Rosebery ore contains more pyrite. It is from this mine that any increased tonnage is expected. The ore is a mass of fine-grained, intimately associated sulphides, with practically no coarse...

Jan 1, 1949

By Thomas A. Printz

The wide use of carbon steel in construction and engineering projects makes this engineering material accountable for approximately 85% of the total annual steel production worldwide. Despite the lack of corrosion resistance of carbon steel, it is incorporated into the permanent work for marine applications, power plants, transportation projects, chemical processing, mining, petroleum production and refining, pipelines, mining and construction equipment. Corrosion is an electro-chemical process that occurs in the presence of water and air. When an electric current is introduced to water or soil, the rate of carbon steel corrosion increases rapidly. Gaseous atmospheric constituents that are capable of electrolytic activity can also increase the rate of corrosion. Corrosion tends to be more rapid in environments in which the steel is exposed to water, and then air, rather than being constantly submerged. The exposure to seawater increases steel pitting because the electrical conductivity is improved in salt water.

Jan 1, 2013

By A. R. Jambekar

City of Bombay has been developed out of former 7 islands. Landmass of 434 sq.km. of Bombay, started looking inadequate for further growth and expansion of Bombay City. In order to develope twin city of New Bombay, State Government formed fully owned Company "City and Industrial Development Corporation of Maharashtra Limited", (CIDCO) in 1971 and entrusted it with planning and development including social and physical infrastructure of New Bombay.Hence, Trans - Thane Creek area is being planned and developed, to serve as counter-magnet to Bombay. Area of 343 sq.km located on the main land, is fast developing into a satellite community, for India's overcrowded financial capital. Thane Creek, running in almost North-South direction, separates Bombay City from main land and posed a significant barrier, to further expansion of city's sprawling suburbs, until, it was bridged for the first time in 1972. On the basis of traffic study, CIDCO decided to construct an additional road link across Thane creek to cope up with future projected traffic. This bridge will connect Airoli in New Bombay and Eastern Express highway near Mulund. Bridging the vast, exposed tidal Thane Creek, have always posed challenging conditions, during constructions of these bridges. In this paper, case history of deep open foundations provided for Airoli Bridge is presented.

Jan 1, 1996

By Zia Zafir

Design of the deep foundations for the loads imposed by lateral spread include the estimate of the pressure applied by the liquefied material as well as amount of anticipated displacement. In the absence of a non-liquefiable cover over a liquefiable layer, it is possible to design the foundation system just for the additional pressure applied by the flow slides. On the other hand, if a non-liquefiable layer exists above the liquefied zone, the foundation should be designed for anticipated movements. To completely account for liquefaction and/or lateral spread and their interaction with the deep foundation system, a coupled soil-structure interaction (SSI) analysis should be performed. However, a complete SSI analysis may not be feasible for most of the projects. This paper will present recent advances in analysis techniques and simplified methods to design deep foundations for liquefaction and lateral spreading. In addition, a case history of the Rancho California Bridge in southern California located within 1 km of the active Elsinore fault will be presented. One of the bridge abutments is underlain by potentially liquefiable layers. The pressure applied by the liquefiable layer was estimated to be greater than the shear capacity of the 36-inch CIDH piles designed for the abutment. However, with limited ground improvement and more careful analyses incorporating structural effects of CIDH piles, resulting design and construction resulted in a factor of safety greater than 1 against slope failure. The recommended approach was generally consistent with the recently published, and AASHTO sponsored, NCHRP 12-49 project regarding seismic design guidelines for new bridges and the effects of seismic displacements against bridge foundations.

Jan 1, 2006

By Ren Xiangwen, Shi Xuefa, Shao Mingjuan, Ye Jun, Yang Yaomin, Li Bing

"The Mid-Atlantic Ridge (MAR), one of the archetypes of slow spreading ocean ridges, extends from the Arctic Mid-Ocean Ridge southward to the Bouvet triple junction making up a significant proportion (~ 40%) of the global oceanic ridge system. During the past few decades, many hydrothermal fields like TAG, Logatchev, Ashasze were discovered along the northern part of the MAR, whereas the southern part, which makes up one third of the ridge (6000km), shows little documentation of hydrothermal mineralization, except for three sites: Site 4°48! the Nibelungen Field, and Lilliput. During March to May 2011, following discovery of three new hydrothermal fields during the 2nd Leg of COMRA's 22 Cruise of the R/V DayangYihao, the 3rd and 4th Legs found another two high temperature hydrothermal fields (SMAR15°S, SMAR26°S), one low temperature field, and several fields with strong turbidity and temperature anomalies in the water column. In this study, we present a preliminarily study of the mineralogy and isotopic geochemistry of the sulfides from SMAR 15°S and SMAR26°S.SMAR 15°S is situated in a SE-NW offset depression of an axial neovolcanic ridge in the median valley, with water depth of about 2793m. In the water column around this field, strong turbidity and temperature anomalies were detected. Ten-meter tall venting chimneys, hydrothermal mounds, as well as a large amount of hydrothermal vent shrimp were also observed and recorded by ROV and deep-tow camera surveys. The samples collected from this field include sulfide chimney fragments, massive sulfides and basaltic rocks. Based on the major metal and the mineral assemblages, three types of sulfides have been identified: 1) Zn-Fe rich sulfides with abundant wurtzite and pyrite zoned fragments, 2) Cu-Fe rich sulfides with much isocubanite and pyrite assemblage, 3) Fe-rich sulfide with massive pyrite fragments. These indicate that this field has undergone at least three phases of mineralization during the venting history."

Sep 1, 2014

By P Blattner

The Late Miocene gold-silver bearing epithermal system at Waihi has some close similarities in its paleo-thermal and geochemical structure with modern, volcanic-hosted geothermal systems such as Ohaaki-Broadlands. At Waihi an extensive braided quartz vein system is enveloped by hydrothermally altered andesites with minor tuff breccias and tuffs. A main stage of vein filling consists of multiple phases of chalcedonic quartz and fine to medium grained quartz, which are accompanied by pyrite, sphalerite, galena, chalcopyrite and acanthite below the base of oxidation. Platy calcite is present locally. Fluid inclusion studies indicate that the main stage quartz was deposited at temperatures of 189¦-273¦C from dilute (Tm of -0.1 to -1.0¦C) fluids that were locally boiling. Homogenisation temperature Th versus Tm data points lie within the field enveloped by dilution and boiling/gas loss paths determined for the Ohaaki geothermal field, and indicates that the parent hydrothermal fluid for the Waihi epithermal system had a similar composition to that at Ohaaki, ie 0.2 wt% equiv NaCl and 3.3 wt% equiv CO2. The hydrothermal alteration mineralogy and the isotopic composition of vein calcite indicate that the hydrothermal fluid contained relatively high concentrations of CO2 , as at Ohaaki. Oxygen isotope analyses of main stage quartz range from 6.1 to 11.6 %0 and of vein calcite from 2.29 to 9.4%0. Calculated d18Owater values for the hydrothermal fluid that deposited the main stage quartz range from 2.0 to -5.7%0, with a trend to less negative values with depth. They are similar to those in the deep chloride fluid in active geothermal systems with a substantial fluid throughput. A high fluid throughput at Waihi system is also evident from the extensive high intensity hydrothermal alteration and large volume of quartz deposited in the vein system.

Jan 1, 1995

By Laurance L. Oden

The Bureau of Mines is developing melting data for binary combinations of the alkaline earth fluorides and yttria to facilitate the formulation of slag compositions. The present report deals with the CaF2-Y203 system for which solidus and liquidus temperatures and solid solubilities were determined. The information is presented as the phase diagram. All specimen compositions were blended from high-purity materials and encapsulated in Mo or Pt20Rh prior toheat treatment. Liquidus temperatures were determined by ceramographic examination of heat-treated and quenched specimens. Solidus temperatures were determined by differential thermal analysis and by electron microprobe analysis of quenched specimens. Terminal solid solubilities were derived by parametric methods. The peritectic system was found to be pseudobinary due to the formation of yttrium oxyfluoride at temperatures near the liquidus. The peritectic point occurs at 7 mole pct Y203 and 1,438° ± 5°C. The terminal solid solubility of Y203 in CaF2 decreases from 7 mole pct at 1,438° C to 1 mole pct at 1,100° C, and the solubility of CaF2 in Y203 decreases from 9.5 to 7 mole pct over the same temperature interval.

Jan 1, 1970

By Jay Rodgers

There has been a longstanding acceptance that burden plays a major role in the magnitude of ground vibration amplitudes generated from surface blasting. Much of the data that this belief is based upon is empirical in nature and may or may not represent an example of false inference. Recent published reports have rightly questioned the influence of burden and confinement on blast vibration amplitude, suggesting that the fracture condition of the rock mass is a better indicator. The increased investment in electronic detonators as a tool to control ground vibration amplitudes demands an understanding of vibration production detailed enough to make use of the vastly improved timing accuracy that they provide. A more accurate relationship may be found if we strip away the assumptions of the past and search for the underlying mechanism of vibration production in surface blasting. We must answer the question: What happens at or near the borehole when an explosive charge detonates that produces ground vibrations?

Jan 1, 2003

By Wojciech Klecan

Cobb County, located on the northwest side of Atlanta, GA, is continually growing and, like many other metropolitan areas, it needs to increase the capacity of its waste water system to meet future demand. The Cobb County Water System (CCWS) is the responsible agency for water distribution, waste water collection and treatment in most areas of the county. CCWS, one of the most progressive agencies in the metro-Atlanta area, is addressing its future waste water capacity needs in the southern part of the county with the construction of the South Cobb Tunnel and Pump Station. This project consists of an 8.8-km- (5.5-mile-) long, 8.2-m- (27-ft-) diameter, tunnel boring machine (TBM) excavated waste water storage and conveyance tunnel; six tangential vortex-flow intakes ranging from 1,533 to 5,700 L/s (35 to 130 mgd) peak flow capacity, two construction shafts, six 1.8-m (6-ft) finished diameter connecting tunnels ranging in length from 6 to 975 m (20 to 3,200 ft) and a 5,700-L/s (130-mgd) wet/dry pit pump station. The pump station will have a semi-circular wet well with a dividing wall that extends almost to the top of the shaft and a spilt dry well for reliable operation. Roller gates will control the flow to the wet well from the tunnel. The pump station will have six 1,420 L/s (32.5 mgd) pumps and two sets of stair wells and elevators. With a finished diameter of 32 m (104 ft) and a depth of 62 m (204 ft), this is the largest pump station shaft constructed so far in Georgia for the dewatering of a waste water tunnel. The pump station shaft was also the highlight of the well attended and successful 2009 Shaft Design and Construction Short Course held in Atlanta, Sept. 10-11. The two-day course was sponsored by the Underground Construction Association of SME and Pennsylvania State University and concluded with a field trip to the pump station shaft. The tunnel starts south of the city of Austell and finishes at the South Cobb Water Reclamation Facility (WRF), located on the banks of the [ ] Chattahoochee River just north of Interstate 20 (Fig. 1). The South Cobb Tunnel will run 30 to 137 m (100 to 450 ft) below the surface, with an average depth of about 91 m (300 ft), through metamorphic rocks (Fig 2). The construction contract was awarded to Shea-Traylor JV with the lowest bid price of $305 million and notice-to-proceed was given on July 14, 2008. Jordan Jones & Goulding, Inc. (JJG) is the project designer and performed the geotechnical investigations. Parsons/Jacobs Associates is the construction manager. The South Cobb Tunnel is CCWS?s second deep hard rock tunnel. The 15.3-km- (9.5-mile-) long, 5.5-m- (18-ft-) diameter TBM excavated the Chattahoochee Tunnel was the first deep tunnel to be construced in Cobb County. Construction began in 2000 and the project was completed four years later. It is located about 16 km (10 miles) northeast of the South Cobb Tunnel in similar geology. It was designed by JJG to meet east Cobb?s long-term waste water capacity needs and provide flow equalization to the R.L. Sutton WRF. The Chattahoochee Tunnel was named ?Outstanding Civil Engineering Project of the Year? by the Georgia Sec-tion of the American Society of Civil Engineers in 2006.

Jan 1, 2009

By S. Fuentes, J. Cáceres

"During the past fifteen years, mines utilizing the block caving method have improved performance and systematically reduced total mining costs.This paper describes improvements in mine design, mine planning, and mine management, including methods enabling the Chilean and international mining industry to ensure cost savings and productivity growth while using the block caving method. These improvements have encouraged the re-evaluation of underground operations at operating and closed open pits, and challenge surface mining applications as the only low-cost mining method. This paper describes a strategy to estimate the optimum open pit to underground transition time during the life of a mine. IntroductionDuring the last fifteen years, block caving mines have experienced huge changes in designs, planning and administration. These changes have permitted operators to drastically reduce costs, improve equipment productivity, and improve overall business performance. As a consequence of this situation, the block/panel caving mining system is challenging actual open pit operations to maximize the net present value (NPV)."

Jan 1, 2004

By J. L. Page, A. C. Marlowe

The Research and Development Services of South Africa has begun underground trials with a Robbins 52RE blindhole borer using a cutterhead fitted with high pressure water jets to assist mechanical cutting. The objectives of the work are to reduce cutter costs by increasing cutter life and to increase overall penetration rates. The paper reviews blindhole boring in South Africa and laboratory experiments in rock cutting assisted with high pressure water jets. The borer and its ancillary equipment are described. Initial results of underground boring experiments are presented. The paper concludes with the test programme for the future.

Jan 1, 1985

By R. W. Watson

A belt-wearable self-contained self-rescuer (SCSR) manufactured by the CSE Corp. and designated the "SR-1OO" was evaluated for safety in the underground mine environment by the U.S. Bureau of Mines. The evaluation consisted of laboratory tests on the chemicals contained in the unit and field trials to simulate the mine environment. This report summarizes the test results and compares the results with those from earlier tests with chemical and compressed oxygen self-rescuers. It was concluded that the new SCSR did not pose any different or more severe hazards than the earlier units. In view of the mine-proven safety record of the SCSR's now in service, no reason could be found to disallow use of the belt-wearable unit.

Jan 1, 1991

By D. Kwietnewski

The 4th bore of the Caldecott Tunnel is a 50-ft horseshoe shaped highway tunnel located in the hills east of Oakland, California. Tunnel excavation was mostly completed using one of the world?s largest commercially available roadheaders, a Wirth T3.20. The geologic profile included seven different geologic units, which displayed a range of different behavior with regard to excavation and initial support. Following a brief introduction to the excavation and support methods, this paper will discuss roadheader performance in the various geologic units encountered during excavation. Comments will also be made concerning the relationship between the roadheader method of excavation and observed ground convergence during excavation.

Feb 27, 2013

By N. Seidle

Numerous studies conducted in the 1960's and 1970's concluded or implied (1) that a high accident rate in terms of severity and frequency exists among new (first year) operators of mine machinery equipment, and (2) that lack of experience and training is a major cause of this high accident rate. Further studies refined this premise to show that the major causes of accidents among first year operators are: (1) lack of manipulative skills; (2) failure to follow/adhere to routine procedures; and (3) failure to recognize and respond properly to hazards. This report describes the design, development, and manufacture of a shuttle car operator training system, including a program of instruction which: ? Is economically feasible. ? Addresses accident data and specific causes of accidents. ? Includes an aerospace quality simulator of sufficient fidelity to teach and develop manipulative skills, recognition of and response to hazards, and routine and emergency procedures. ? Is designed to significantly reduce the severity and frequency of accidents especially during the operator's first year. ? Is designed to significantly improve the performance of the trainee as compared to the standard learning curve. Development of the simulator produced several valuable by-products including a major state-of-the-art technological advance in visual systems for simulators, and a first-time application of (certain) advanced filming techniques to underground filming.

Jan 1, 1984

By M. Nduna

Surface properties of metal sulphides have a great significance in various areas of engineering and science, such as acid mine drainage, contaminant sorption, and metal separation. In various attempts at producing metal sulphide particles from synthetic solutions, prodigious quantities of nuclei that grow only to colloidal dimensions have been frequently reported. This copious nucleation is promoted by the high levels of supersaturation that characterize most precipitation reactions. Colloidal particle formation in precipi¬tation-based separation processes results in sub-optimal solid-liquid separation, which is alleviated by the production of more highly crystalline particles or agglomerates. The current work approaches this challenge from an electrochemistry perspective, by measuring surface charge potential of precipitant particles during metal sulphide precipitation with respect to the concentration of metal sulphide lattice ions in solution. Electrophoresis was used to measure the metal sulphide particle zeta potential and the settling properties were obtained by performing settleability measurements using an Imhoff settling cone. A suspension of copper sulphide particles was precipitated from synthetic solutions of copper and sulphide ions at equimolar concentrations. Immediately after precipitation the copper sulphide particles had a zeta potential of -50 mV and a settleability of about 7 ml.l-1. With the addition of copper ions the settleability increased by a factor of nearly three times and the zeta potential also increased to a maximum of -40 mV. A decrease in zeta potential to a minimum of -60 mV was observed after the addition of sulphide ions and this was associated with a settleability of 0 ml.l-1.

Jan 1, 2013