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By S. S. Huyett

The opportunity to cooperate with the Mining Department of the Pennsylvania State University in their Student-Trainee Program is accepted by The New Jersey Zinc Company who believes that the participation in this type of a program will lead to a larger supply of high calibre engineers in mining. Trainees compete with other employees to earn the cost of their education while gaining practical experience in the mining industry. The practical experience is arranged to complement the technical education through a variety of work assignments. Job opportunities for the trainee are related to the work requirements of the Company and to the performance of the trainee. Management must consider and deal with a good many problems uncommon with regular, full 'time employees. For a number of reasons this program is recommended to other companies as a means to encourage outstanding young men who are interested in a career in the mineral industry to obtain a professiona1 education.

Jan 1, 1963

By Don K. Smith

The northern zone of the Indus Basin comprises a vast area of essentially level land in West Pakistan which is irrigated by means of a complex system of canals that distribute more water to more land than any other irrigation system in the world. In spite of the development of this extensive irrigation system, production of food and fiber has not met the requirements of the country. The major reasons that crop production has not reached anticipated levels are the lack of adequate irrigation supplies and effective subsurface drainage. As a result, yields per acre are among the lowest in the world for areas where irrigation is practiced, and many thousands of acres of valuable crop land have been removed from production or are seriously affected by salinity and waterlogging. To rectify the problems of irrigation supply and drainage the Government of Pakistan has undertaken a program of Salinity Control and Reclamation which is being administered by the Water and Power Development Authority. The Authority retained Tipton and Kalmbach, Inc. , of Denver,, Colorado as Engineers for the program in the northern zone of the Indus Basin. -This program consists of the construction of about 30, 000 irrigation wells to provide drainage for waterlogged lands and full irrigation supplies, including leaching requirements, for; all cultivated lands. The program will ultimately ensure the productivity of 20 million acres and will involve an annual pumpage from ground water storage of nearly 40 million acre-feet of water. The value of the crops produced when the program is in full operation will be 4 to 6 times the value of the crops that could be produced without the benefits of this program.

Jan 1, 1967

By Wescomb R. Jones

The United States is the world's largest producer of hydrofluoric acid (HF), with its 1971 output of 317,000 short tons representing about 40 percent of the estimated Free World production. U. S. production has increased over five fold in the past 20 years, with a growth rate of about 7 percent per year between 1960 and 1970. However, the growth rate to 1977 is expected to be less than 5 percent per year, due primarily to a reduced rate of growth in requirements by the aluminum industry and an expected increase in imports from Canada and Mexico. This discussion will include our analyses of the consumption pattern for HF in 1972 and the factors influencing the demand forecast for 1977.

Jan 1, 1973

By Clay Haynes, Tim Pearia, Robert Robinson, Judy Cochran

A 1.89 km-long, 4.5 m-I.D. tunnel was successfully constructed through saturated hard clay, and highly abrasive dense sand and gravel, with groundwater heads ranging from 10 to 20 m. In order to address these conditions, a Lovat earth pressure balance TBM was used, with soil conditioning by foam, water and various polymers. Support was provided by a single-pass segmented concrete lining. Groundwater inflows of 400to 1,600 lpm at times created challenges for changing cutting tools. Surface settlements were generally less than measurement thresholds, except under very low cover at startup. This project provides a pivotal case study of the successful application of EPBM technology in saturated, abrasive glacial soils and the successful application of soil conditioners.

Jan 1, 2003

By I. M. Konduri

Theoretical investigation and laboratory experimentation have shown a great potential for jet fan ventilation in mines. Jet fans, also called induction fans due to the induction effect of the fluid jet to ventilate headings, may have particular application in remote-controlled production operations. This paper summarizes ongoing research using a scaled laboratory model. The model uses water as a fluid medium and simulates a typical 25m long heading of 1.5mx6m cross-section. The effects of various nozzle positions and designs have been investigated by using still photography as a tool for flow visualization. It is also found that the use of jets in combination with line curtains has enhanced the overall ventilating effect in the model entry.

Jan 1, 1996

By N. R. Sainath

This paper discusses the results of a laboratory investigation carried out to study the microscale flow characteristics of copper ores and the variation in flow behavior resulting from flow of leach solution. Fractures in 1.5 and 4 inch diameter cores were mapped by visual inspection. The cores were stressed in a triaxial stress field representative of in situ conditions. The permeability of the samples to water was then estimated. The samples were exposed to 20 g/l sulfuric acid and the experiment repeated. The Permeability of unleached samples ranges from 10-1 to 10-19 m2 and it increases as leaching progresses. The porosity variation and the rate of recovery of copper from the specimen during leaching were also studied.

Jan 1, 1991

By Sergio Estebanez, Martha Gross, Ruben Rubal, Yvonnick Rescamps, Alexandre Cochennec

The Hampton Roads Bridge-Tunnel (HRBT) Expansion project in coastal Virginia, USA will add two 1.5-mile (2.4 km) TBM bored tunnels alongside two existing immersed-tube tunnels between artificial islands. The site’s unusual constraints and the requirements of a large-diameter variable-density TBM shaped the design-builder’s decisions for handling TBM inputs and outputs, siting the TBM plant and supporting equipment, and sequencing tunnel-construction operations. This paper addresses the logistics necessary to enable key functions of the 46-ft (14-m) TBM and its ancillary equipment, including transport of most materials by barge, U-turn of the TBM on an artificial island, and delivery of materials for the second tunnel through the first one while interior structures are under construction.

Jun 13, 2021

By S. C. Sun

The grinding of coals for coal preparation has been studied extensively by previous investigators, but no similar work has been done on coal lithotypes (l-4). However, the different natural breakage characteristics of coal lithotypes have been recognized and utilized by the coal industry (5,6) to develop the Longway Burstlein process (7) for the concentration of macerals(8). The specific objective of this research was to determine the relative grindability of lithotypes, obtained from both anthracite and bituminous coals. An attempt was made to relate the findings, wherever possible, to the chemical and physical properties of the tested lithotypes. Another aspect of this research was to ascertain the size distribution and grindability of lithotypes ground at a various number of revolutions in a Hardgrove mill.

Jan 1, 1970

By J. D. Shenk

The White Cliffs diatomite deposit occurs in a lacustrine facies of the Quiburis Formation, an Upper Miocene to Pliocene basin-fill sediment of the lower San Pedro Valley. On-going geo-logic mapping has defined an 2.5-3.0 m (8-10 ft) thick ore zone near the mill site, several marker beds, a NNW-trending high-angle normal fault, and a NW-trending syncline. The diatomite has an average loose-weight dry bulk density of 130 kg/m3 (8 lbs/ft3) and is presently marketed outside Arizona for asphalt filler. Current development is projected to yield 3500 mt (4000 st) of finished product, with an estimated 91,000 mt (100,000 st) of finished product obtain-able from several other nearby sites.

Jan 1, 1988

By Paul Richardson

This paper discusses the drilling techniques and equipment used by Loffland Brothers Company to drill the AEC's UC-3 large diameter shaft in Nevada. Included are pictures and illustrations of the drilling-mud circulating system, the surface and downhole drill-string and the special heavy-duty mast and hoisting equipment required to do the job. The purpose and method of lining the large diameter holes along with the technique and materials used to backfill the lining to hole annulus are discussed briefly. Areas requiring improvement in both equipment design and technology for large diameter shaft drilling are discussed briefly. Shafts as large as 140 inches in diameter to depths of 5,000 feet can be drilled with existing equipment and technology.

Jan 1, 1969

By Chris D. Breeds

Northwest Boring, Inc. (NWB) deployed a skinned up AVN 2000AB Microtunnel Boring Machine (MTBM) to install 7.5-foot long, 118-inch outer diameter reinforced concrete pipe (RCP) sections along an alignment between the Fremont (FRS) jacking shaft and the 3rd Avenue (3RS) receiving shaft for the Ship Canal Water Quality SCWQ Project. The alignment includes: a 67-foot long straight section, a 367-foot long curved section excavated along a 650-foot radius curve, followed by a 182-foot long straight section. This paper describes the project including planning and design, manufacturing, equipment installation in the 90-foot-deep FRS jacking shaft, egress through the secants and microtunnel operations required to complete the shaft and install the required casing pipes.

Dec 1, 2022

By Eugene Honeycutt, David Gallagher, R. E. Melley, Nick Madison

Drummond Co. Inc.'s Shoal Creek Mine slope conveyor is the highest lift, highest horsepower, highest tension conveyor system in North America. The system has a capacity of 4950 t/h (5500 tph), a vertical lift of 360 m (1180 ft) and a total connected power of 6000 kw (8000 hp). The mine will include 2 longwall machines and 5 to 7 development sections. Annual raw production will approach 9 million tly (10 million tpy). This paper describes the early investigation of system capacity, haulage system options, and the final selection of a single flight belt conveyor. It will review the basic system de- sign and equipment selected. Also included will be some highlights of the installation of the conveyor system.

Jan 1, 1996

By K. M. Belingheri, M. E. Smith

Pinson Mining Co. operates a conventional mill and two heap leach operations in north-central Nevada. The latest of these heap leach operations, the Preble project, is a low-grade, low-tonnage property made profitable through several innovative capital reduction techniques. Rapid return on investment was a prime factor in design. To facilitate this, fast-track design and construction techniques were employed. The project is a seasonal 1.5 kt/d (1 700 stpd) crush/agglomerate heap leach plant using both clay and plastic leach pads. Construction and startup were achieved through cooperative arrangements between local contractors and in-house construction personnel, with few items put out to bid. An interactive approach to design minimized lost time and construction costs.

Jan 1, 1987

By Jeff Hussey

Since 1955, Gaspe Mines has produced 150 Mt (165 million st) of ore averaging 0.9% copper. The ore was mined from two open pits and from underground workings. In 1994, four exploration drill holes discovered a buried porphyry/skarn copper-molybdenum (Cu-Mo) deposit at depths of between 1,000 and 1,700 m (3,280 and 5,580 ft) below the top of Porphyry Mountain. The mineralization and alteration associated with the Porphyry Mountain quartz monzonite does not outcrop. Prior to 1997, about 19,500 m (64,000 ft) of drilling in 12 drill holes had outlined 200 Mt (220 million st) grading 0.73% Cu and 0.08% Mo. Mineralization occurs as veins and disseminations of chalcopyrite and molybdenite.

Jan 1, 1998

By Frank W. Bowdish

Studies of sulfidization and flotation of chrysocolla involving the use of pH and sulfide ion instruments, a Zeta meter, microflotation techniques, and sensitive determinations of adsorbed sulfur have given new insight into the mechanism of the process. Factors that affect the recovery of sulfidized chrysocolla by flotation appear to be the pH at which it is sulfidized, and certain alterations of the surface that occur during aging after sulfidization. Such aging results in increased recoveries. The surface charge, as measured by electrophoretic mobility, of chrysocolla shows an unexpected negative increase as pH values are changed from 6.0 to about 4.5, and this appears to be correlated with increasing sulfur adsorption and flotation recovery over the same or even wider pH ranges.

Jan 1, 1970

By Matthew E. Fowler, Jean Habimana, Roy F. Cook

The West Side CSO Tunnel, Pump Station & Pipeline Project is currently beginning construction along the downtown waterfront of Portland, Oregon. This4.3 meter diameter, 5,500 meter-long soft ground tunnel will be driven along the westbank of the Willamette River adjacent to buildings and utilities and several major pile-supported bridges. High groundwater pressure, extended lengths of gravel to cobble-size alluvium, and the need to control ground loss and surface settlements were key considerations in the selection of slurry tunnel boring machines for the project This paper presents an overview of the numerical modeling that was performed during design to estimate the strains and additional loads in the pile-supported structures and to assess the efficiency of proposed mitigation measures.

Jan 1, 2003

By Robert L. Runkel, D. Kirk Nordstrom, James W. Ball

Low-flow reactive-transport processes in Wightman Fork downstream of the Summitville Mine, south-central Colorado were simulated using the OTIS and OTEQ solute-transport models. The simulation was calibrated using data from a synoptic study conducted during October, 1998. Discharge over the 8-km reach from just below the mine site to the Alamosa River confluence ranged from 0.077 to 0.17 m3/s; travel time was 10.7 hours; pH ranged from 4.6 to 5.7. Simulations revealed that mass balance for SO4 was maintained, and that pH, Fe, and Al were non-conservative. Simulations allowing hydrous ferric and aluminum oxide or hydroxysulfate precipitation matched observed water quality conditions more closely than simulations without precipitation.

Jan 1, 2000

By B. E. Dindsale, P. B. Altringer, R. H. Lien

The Bureau cf Mines, U.S. Department of the Intericr, is investigating biolcgical and chemical deccntaminaticn of cyanide- containing leachates and residues. Biolcgical cyanide cxidaticn, using bacteria isolated from a precious metals tailings pond, destroyed >85 pct of the cyanide in several prccessing solutions containing up tc 280 ppm CN. Reaction time varied from about 4.5 hr in a trickling reactor using quartz as a bacterial substrate to 2 mo in unagitated, covered flasks. Chemical techniques were used to destroy the remaining complexed cyanide down to 1 ppm. Exploratory tests were also conducted using spent ore from heap leach operations as the bacterial substrate to determine if biological cyanide oxidation could be used to destroy the residual cyanide in spent heaps.

Jan 1, 1991

By J. R. Batista, J. C. Young

Leachates from gold heap-leaching mines may contain selenium concentrations as high as 2 mg/L. Previous studies report satisfactory selenium adsorption by activated alumina from relatively "clean" drinking waters. However, the findings of these studies cannot be directly applied to the treatment of mine leachate where other ions compete for the alumina adsorption sites. This study evaluated the adsorption of selenium from a mine leachate to develop design parameters for a full-scale activated alumina process. The study revealed that 68% of the selenium in the leachate could be removed by alumina at pH levels greater than 5.0. At pH levels less than 4, silica was poorly adsorbed by alumina, and selenium adsorption was improved. Silica adversely affected the selenium adsorption capacity.

Jan 1, 1998

By M. A. Mahtab, N. M. Cruickshank, M. T. Wane

Gas outbursts occur as sudden eruptions of gas and minerals from the face of a mine heading as the heading approaches potentially burst prone (or anomalous) zones of rock. Such outbursts have resulted in considerable damage to equipment, and in some cases lives have been lost. Characterizing these anomalous zones and detecting their presence is therefore vital to safe mining. Certain significant characteristics associated with the outburst-prone zones are: (1) the presence of fluid inclusions, (2) unstable stress conditions, (3) characteristic geologic structures, (4) certain physical properties of the rock, and (5) microseismic activity. Geophysical and engineering methods for detecting these characteristics are discussed and are considered with respect to their past success and future potential for predicting gas outbursts.

Jan 1, 1987