Search Documents

By R. A. Jankowski, J. J. McClelland

Laboratory tests were conducted by the U.S. Bureau of Mines to determine the respirable dust reduction effectiveness of and interaction between face airflow and water sprays for a continuous miner. Exhausting face ventilation was varied from 3,000 to 9,000 cfm (1.42 to 4.25 m3/sec). Spray-water-flow was varied from 15 to 35 gpm (0.057 to 0.132 m3/min), while nozzle operating pressure was varied from 80 to 200 psi (5.62 to 14.06 kg/cm2). Results from gravimetric dust samples indicated that airflow had the greatest individual impact on reducing dust levels, with return and operator concentrations reduced by as much as 57% and 99%, respectively. Interactions between dust control parameters were found to be significant. Often, these interactions defined a level of application for a control parameter where further increases in that parameter failed to produce additional reductions in dust concentrations. In several cases, increases in a control parameter resulted in higher dust levels at the operator's location. These higher dust levels were attributed to additional rollback and/or airflow turbulence. Regression modeling indicated that increases in airflow to 8,400 cfm (3.96 m3/sec), water flow to 25 gpm (0.095 m3/min), and water pressure to 140 psi (9.84 kg/cm2) typically were beneficial at the operator and return sampling locations.

Jan 1, 1991

By Harry Sutcliffe, Francis M. Keville

The paper describes the, impact of the geotechnical exploration program on the line and grade of the tunnels and the shaft configuration on the Red Line Extension N.W. in Cambridge and Somerville, Massachusetts, and comments on several aspects of the implementation of the project.

Jan 1, 1983

By E. M. Abraham

The establishment and survival of different grass species and cultivars on various phytotechnic treatments at a limestone quarry was studied. The treatments applied were: a) bare soil, b) bentonite, c) bentonite-straw and d) asphalt-straw. According to the results, significant differences were found among species and cultivars, growing on different treatments as far as plant growth and survival are concerned. The seed germination was higher on bentonite -straw and asphaltic-straw than on bentonite but the plants survival were higher on bentonite. Lolium perenne had higher seed germination rate and better establishment than the other tested species at all treatments. However, the survival rate of Agropyron desertorum and of the cultivars palestina and chrysopigi of Dactylis glomerata was higher than of the other species.

Jan 1, 2007

By A. M. Marabini, V. Alesse, Belardi. G.

An alternative flowsheet was designed for the flotation treatment of a complex sulfide ore from the Sotiel Mine in Spain. The ore contains 0.71% Cu, 2.24% Pb and 5.63% Zn. Two specially developed synthetic collectors, methyl-mercapto-benzoxazole (MMBO) and 6n-propoxy-mercapto-benzo-thiazole (PMBT), were examined. MMBO exerts a specific action on copper and zinc minerals after treatment with copper sulfate, and PMBT exerts a specific action on Pb minerals. Flotation operating variables (pH, frother type, frother quantity and feed particle size) were examined by means of rougher flotation tests to determine the optimum conditions for the new collectors. Once the optimum conditions were determined, a series of open flotation circuits were run on feeds of various particle sizes (obtained by different types of grinding). The objective was to obtain high-grade Cu and Zn concentrates. The results of the open-circuit tests demonstrated that a Cu concentrate grading from 18% to 23% Cu and a Zn concentrate grading from 40% to 48% Zn can be produced.

Jan 1, 1996

By R. L. De G. Solms

INDEX 1. INTRODUCTION 2. FLOODING 3. THE PLUG 4. THE FIRST ATTEMPT 5. THE SECOND ATTEMPT 6. PUMPING 7. TIGHTENING OF THE PLUG 8. SHAFT REPAIRS 9. POST-MORTEM 10. CONCLUSION

Jan 1, 1987

By Claude Boisjoly, Pierre de Courval, Don Nguyen

The Sainte-Marguerite-3 (SM3) hydro project, presently under construction, requires the excavation of an underground powerhouse and large water conveyance tunnels. This paper describes the planning of the project, main features of underground structures, excavation techniques and ground support.

Jan 1, 1997

By J. E. Bernick, J. Davies

This paper describes the design and construction of a 22.86 m (75 ft) long jacked tunnel, which was successfully installed, despite difficult mixed face conditions at Metro-North’s Westport Station, in Connecticut in the fall of 2003. The tunnel utilized what is believed to be, the first application of a steel grillage system within the United States. This grillage was installed before the jacking started and allowed the tunnel to be jacked under four live railway tracks, which included the Acela high speed line, without affecting train operations. The clearance between the top of the tunnel and the rails was only 0.9 m (3 ft).

Jan 1, 2005

By M. G. Bakker, D. D. Murphy, D. R. Spears

The US Bureau of Mines studied the mechanism of shear flocculation of silica with stearic acid. At pH 6 and 12, shear flocculation of silica was not observed with the addition of up to 4.5 x 10-4 M (5 lb/st) stearic acid. However, in the presence of 0.1 M NaCl at pH 6, shear-flocculation was observed at stearic acid concentrations = 10-4 M (22.5 lb/st). Adsorption of stearic acid on silica was studied using stearic acids spin-labeled with a doxyl group. The presence of the spin-labeling group did not greatly affect the shear flocculation properties of stearic acid. Adsorption of labeled stearic acid on silica was measured as a function of surfactant concentration with electron paramagnetic resonance (EPR) spectroscopy and gas chromatography (GC). The GC results indicated that the stearic acid was predominately adsorbed on the surface at concentrations above 10-4 M. From the EPR spectra, the formation of aggregates of stearic acid was apparent at concentrations of approximately 10-5 M (22.5 lb/st). The results are discussed in terms of a possible mechanism for shear flocculation.

Jan 1, 1995

By Chen Bingchen, Zhang Jian, Liu Jiaxiang

The influence of various installation angles of hydrocyclone on its operation indexes was investigated, and the correspondent mathematical models were established in this paper. The models developed in this paper can be used to the optimizing control of hydrocyclone and make the hydrocyclone as a particle size sensor.

Jan 1, 1995

By S. Duyvesteyn, L. Enloe, P. A. Schmitz, W. P. Johnson

The characteristics of gold leaching from carbonaceous matter by sodium cyanide, and sorption of gold cyanide to carbonaceous matter in autoclaved and non-autoclaved gold ore from Barrick Goldstrike Mines Inc. (BGMI), Nevada, was investigated. Much greater gold cyanide complex sorption was observed for the carbonaceous matter in high preg-robbing ores relative to the low preg-robbing ores. This observation corroborates previous reports that have attributed observed preg-robbing behavior to the carbon in the ore. Gold cyanide complex sorption was found to be reversible for carbonaceous matter from low preg-robbing ore, but was irreversible for carbonaceous matter from high preg-robbing ores. Autoclaving the ore appeared to enhance the sorptive behavior of the carbonaceous matter from both high and low preg-robbing ores.

Jan 1, 1999

By Ronald J. Searle, Howard S. Latham

In April 1964 the Bureau of Reclamation awarded the first contract for rapid machine excavation of a water conveyance tunnel . Since then the Bureau has excavated seven tunnels with a total length of over 190,000 feet utilizing rapid excavation tunneling machines. Tunnel bored diameters have varied from 9' 0" to 20' 10" (See Table #1) and tunnel lengths from 5,000 feet to 67,000 feet. Driver and cutter units varied from 43 rolling teeth and eight rolling discs mounted on a rotating head driven by five 200 HP 23,000 volt electric motors to 20 discs and one tricone unit mounted on a rotating head driven by two 100 HP 440 volt motors. All tunnels were driven with a laser beam guidance system governing both line and grade. Trailing conveyors and rail haulage systems were used to dispose of the excavated material. Approved Bureau of Mines diesel locomotive engines for waste trains were prevalent power sources supplemented by battery units on some projects. Sandstone, conglomerates, agglomerates, siltstone, shale, and granite were the geological formations encountered, with sandstone and shale the preponderant material . Tunnel support systems utilized were structural steel ribs; rock bolts and metal plates; and shotcrete, or combinations of these. Progress varied from 51-1/2 feet to 154 feet per working day for three shifts, depending on rock material and supports required. One contractor established a record rate of advance of over 400 feet in one day, 1,905 feet in one week, and 6,848 feet in one month. Such diversified experience in underground machine excavation methods presented an excellent opportunity to observe, analyze, and evaluate associated environmental health problems. Also, to develop measures for controlling

Jan 1, 1997

By E. Yiğit, M. N. Saridede

Correction to: Mining, Metallurgy & Exploration. https://doi.org/10.1007/BF03402385 The original online article has been revised to correct the author names. Publisher’s Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. The online version of the original article can be found at https://doi.org/ 10.1007/BF03402385 * M. N. Saridede theng@smenet.org 1 Metallurgical and Materials Engineering, Yildiz Technical University, Istanbul,

Dec 23, 2021

By David J. Kruse

Accurate field measurements are essential when validating a conveyor design. They are fundamental in determining a conveyor's behavior, its long-term maintenance requirements, and the life expectancy/ condition of the installed equipment. Field measurements are also invaluable in forensic engineering, particularly when vital equipment has failed This paper will discuss a wide variety of data acquisition equipment, field measurement techniques and accuracies achieved State-of-the-art, custom designed monitoring equipment, as well as, ''08-the-shely instruments and sensors, will be discussed.

Jan 1, 2004

By R. R. Tatiya

The selection of a mining method for a particular deposit must be based on certain technical and economic criteria. This can be interpreted as maximizing extraction and productivity while maintaining safe working conditions and minimum costs. The methodology developed here examines some of these aspects. The proposed methodology was tested on copper deposits that could be mined by underground stoping methods such as sublevel stoping, cut-and-fill stoping and their variants. In general, it provides a practical approach to both method selection and optimum stope design for base-metal deposits.

Jan 1, 1998

By Bruce Gellar

For the past six years, the author has made it a priority to attend the Prospectors and Developers Association of Canada’s (PDAC) annual conference. This most recent meeting took place March 10-13, 2002in Toronto, Ontario. In the three years since the author’s last PDAC report, the mining industry has undergone a severe trough. Some the industry’s woes included deeply discounted commodity prices, rampant layoffs, mergers, and overall avoidance by the investment community. However, at each of the PDAC conferences, the author has felt a heightened sense of excitement about the mining industry, more so than at other similar gatherings.

Jan 1, 2002

By Angus Campbell, Michael J. Gobla

Numerous techniques for treating, controlling, and preventing acid rock drainage have been applied at the Summitville Mine Superfund Site. Challenging aspects of the remote mine site include the wide-spread occurrence of acid-generating soils and rocks, extensive surface and underground mine workings, and a cold and wet climate. Water treatment was an immediate necessity when the Government took control of the abandoned site in December of 1992. Subsequent reclamation activities have emphasized prevention and control of ARD to minimize future water treatment requirements. A combination of conventional, innovative, and experimental methods are being applied to successfully mitigate ARD at Summitville.

Jan 1, 2000

By Thomas de Lange

Extensive test work performed on the Coalscan 3500 ash analyzer at the Grootegeluk Coal Mine has led to the successful implementation of on-line ash monitoring to control the quality of coking coal and power station coal. Test work results are given and the advantages of on-line bias compensation discussed. Some details of the quality control systems subsequently implemented are also highlighted. Finally, the economic benefit of on-line ash monitoring based on the Mayer curve is demonstrated.

Jan 1, 1992

Anhydrite-based dam constructions, which have been implemented successfully in other geological formations, were investigated with regard to their suitability in salt mines. The laboratory investigations show that anhydrite-based building materials with suitable additives bind safely in spite of the high temperatures in salt mines which normally pre-vent hydration. The dependence of the compressive strength, swelling behavior, porosity and permeability upon the choice and ratio of binding material components and additives was determined. Based on the results of these investigations, a pilot-scale experiment was carried out at the GSF Research Mine Asse (Germany) using a mixture suitable for the prevailing conditions

Jan 1, 2004

By Nikolay M. Sirakov, Michael L. Feves, Rumen P. Mironov, Daniel R. Hack

Subsurface investigation of sand and gravel deposits has generally been limited to test pits and borings. These techniques are problematic in terms of the accuracy, usability, and cost of the final data. Innovations in the application of geophysics have been gaining acceptance in the aggregate industry, especially to determine depth to bedrock and the extent of uneconomic inclusions. This paper presents a system to optimize the processing and evaluation of electrical resistivity data. The system uses 3D separation, geometrical reconstruction, and visualization of subsurface objects.

Jan 1, 2002

By L. B. Kirk, A. R. Kirk

At New World, Au-Cu-Ag mineralization occurs in stratiform car-bonate-hosted, massive sulfide-iron oxide, and skarn-replacement deposits. Regional pyritic-alteration, local massive sulfide mineralization and mine wastes generate acid drainage within the district. Water quality improves down gradient through dilution and mixing of acid and metal-rich mine water with bicarbonate-rich, low-metal surface and groundwater, and precipitation of metal-rich ferrihydroxide phases. Natural deposits of ferricrete indicate that pre-mining ARD has occurred, providing important clues to pre-mining water quality. The geoenvironmental model identifies the Cu-skarn mineralization as the primary target for ARD management. Closure success will be limited by the geoenvironmental nature of the natural mineralization.

Jan 1, 2004