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By V. G. Papangelakis

The implementation of a flow-through yttria-stabilized zirconia (YSZ) sensor for pH measurements in high temperature and concentrated electrolyte systems relevant to hydrometallurgical processing of nickeliferous laterites is discussed. Instrumentation involved the use of a custom made flow-through titanium electrochemical cell. Accuracy and validity of the pH measurements at temperatures up to 250C were assessed using concentrated sulphate process solutions ranging from synthetic binary sulphuric acid ? water solutions to progressively multicomponent metal ? sulphate solutions simulating laterite Pressure Acid Leach conditions. The measurements were also compared with theoretical models using recently obtained thermodynamic data. A difference of ±0.25 pH units was observed between measured and calculated pH values at temperatures. This is an acceptable difference given that these are the first direct high temperature pH measurements ever on the concentrated acidic sulphate solutions. This result is encouraging more research for the development of industrial electrochemical systems for direct pH measurements in autoclaves.

Jan 1, 2003

By Thomas S. Lovering

Hot springs, geysers, steam-emanating fumaroles- these creatures of nature were until recently little more than geological curiosities, but today they are exciting the interest of engineers around the world for it has been shown that such hyperthermal areas can be profitably harnessed by man to provide heat and power for his communities. Although water from hot springs was used centuries ago to heat some Korean dwellings, is being used today by one-third of Iceland's population for similar purposes, and is finding industrial applications in New Zealand and elsewhere, the most dramatic use of geothermal energy has been its conversion into electricity. The largest installation at the present time is that at Larderello, Italy, where the Count of Larderello began to experiment in the production of electricity from geothermal steam in 1904. Eight years later after a quarrel with the local power company, the Count installed his first steam turbine, a unit of 250 kw capacity.

Jan 9, 1965

By Thomas Elliott

It is now clearly evident that 1963 is witnessing a record year for prospecting and exploration in British Columbia and Yukon Territory, as substantiated by the following facts: ? About 60 large mining companies and many smaller ones are active in the search for new ore deposits. ? More than 500 prospectors and exploration geologists have been in the field this season. ? It is estimated that $10 million has been spent this year on the search for new ore deposits. ? Claim staking in B. C. to July 31, totalling 14,250, is up 2000 over 1962. ? Helicopter companies report a record total of 25 aircraft chartered to mining groups, with additional numbers used in oil-gas exploration. ? Leading assayers state that business with the industry is double that of the previous year. ? Diamond drillers report an increase of approximately 25% in the amount of contracts now on hand. The question is often asked, "Why is mining so active in Canada's Pacific Northwest?"

Jan 12, 1963

By A. A. Odunaike, E. G. Okafor, M. H. Mokwe

Microscopic Studies were performed on ore samples from the Muro banded iron ore deposit in Nigeria and the Marampa iron ore deposit in Sierra Leone. Ore characteristics that affect processing of both ores were compared with a view toward assisting mineral processing engineers in choosing the most suitable methods for upgrading the ore. The Nigerian ore contains 30% to 37% (by weight) Fe and the Sierra Leonean ore contains 34% to 51% (by weight) Fe. Hematite is the main iron mineral in both ores. The Sierra Leonean ore is relatively coarse grained (typically around 250 µm) and can be upgraded by conventional gravitational methods. In contrast, the Nigerian iron ore is fine grained and must be ground to -74 µm to liberate the hematite for recovery by flotation. Both ores contain high percentages of phosphorus and sulfur, which are above the required specifications for direct reduction and blast-furnace practice. These deleterious elements can be rejected by grinding and flotation.

Jan 1, 1999

By Wilkins C

The Browns Creek deposit is located 8 kin west of Blayney and 220 km west of Sydney (Figure 1), at lat 33¦32'S, long 149¦10'E on the Bathurst (SI 55-8) 1:250 000 scale map sheet. The total measured, indicated and inferred resource at 30 June 1997 was 1.29 Mt at 6.39 g/t gold and 0.45 per cent copper. During the 1996 - 97 year 263 557 t of ore at 6.30 g/t gold and 0.48 per cent copper was treated, to produce 47 496 oz of gold, and 1 169 t of contained copper in concentrate. As the result of an increase in the resources and reserves, because of underground exploration drilling and accelerated mine development, 1997 production at Browns Creek is predicted to expand from 240 000 to 390 000 tpa, to yield more than 70 000 oz of gold per year.

Jan 1, 1997

By W. W. Bristol

The Jerritt Canyon Joint Venture project is located approximately 50 miles (80 km) north of Elko. Nevada, U.S.A. and produces between 250 and 300 thousand ounces of gold annually. The Joint Venture is 70% owned by Independence Mining Company and 30% owned by Meridian Gold Company. Independence Mining Company is the operator. The Jerrin Canyon Joint Venture started operations in 1980 mining a series of open pit mines. Since the early 1990's, the discovery of deeper ores has required the joint venture to develop and mine a significant portion of its annual production utilizing underground mining methods. Underground production started with the West Generator Mine in 1993 followed by the Murray Mine in late 1994. Presently, two additional underground projects are being developed. Underground mining at Jerritt Canyon is budgeted to produce 128 thousand ounces in 1997. This paper documents the major transition/redevelopment of the Jerritt Canyon mining methods.

Jan 1, 1997

By J. F. T. Agapito

Two flat-lying trona seams 3-to 3.5-m thick, approximately 10 m apart, and at depths of 250 m are mined by room-and-pillar at OCI's Big Island Mine in Wyoming. Continuous miners and a yielding pillar system have contributed to improvements in resource recovery and productivity. Long-term stability with minimal subsidence is needed for a large portion of the mine beneath the Green River channel. This was investigated by computer modeling in 1990. Although results of the study indicated good long-term stability, recommendations were made for stress determinations to verify the model. Stress determinations made in 1997 showed pillar stresses 10% to 20% higher than the model stresses, and barrier pillar stresses 10% to 15% lower. This implies that higher panel stresses will be transmitted from the upper to the lower seam. A stability evaluation of the lower seam is planned before two-seam mining to assess entry widths and support requirements.

Jan 1, 1999

By Matthew Janes

Advantages: Clean samples Low sample disturbance Very low spoil Versatile Fast Penetrates all formations Resonant Drill 100 or 150 kW Self tuning to resonance Rotation to 100 rpm Increased depth in dense soil Increased productivity Reduce water use Reduce casing plugging

May 1, 2013

By J. W. Dini

Introduction The mission of the Materials Fabrication Division (MFD) is to provide fabrication services and technology in support of all programs at Lawrence Livermore National Laboratory (LLNL). MFD involvement is called for when fabrication activity requires levels of expertise, technology, equipment, process development, hazardous processes, security, or scheduling that is typically not commercially available. Customers are encouraged to utilize private industry for fabrication activity requiring routine processing or for production applications. MFD is .a large diversified service organization including approximately 400 full time employees. The group provides a wide variety of processes including all common machining and fabrications operations, laser and water jet cutting, electrical discharge machining, lapping, electron beam and laser welding, vacuum brazing, heat treating, forming, electroplating and metal finishing, optical polishing and grinding, vacuum coating, vacuum engineering and a variety of plastics operations. These operations occupy more than 1,250,000 square feet of floor space. For more detail on the many fabrication related services available from MFD, see Reference 1.

Jan 1, 1992

By F. Dehghani

The influence of different grinding methods on the shape characteristics of magnetite particles was investigated. Also, the effect of particle shape on the flotation of the magnetite, both alone and in the presence of quartz particles, was investigated. The shape characteristics of the magnetite particles were measured and calculated from images obtained by scanning electron microscopy via an image analysis system. The flotation tests were performed using a laboratory flotation cell. Results showed that in the -250+212 µm and -106+75 µm size fractions, ball mill products have a higher elongation value than rod mill products, while in the -150+125 µm size fraction, rod mill products have a higher elongation value. Particles with higher elongation values and lower roundness values have a higher flotation kinetic constant. Furthermore, the influence of magnetite particle shape on flotation is greater, and the flotation kinetic constant is higher, in the presence of quartz particles than in the flotation of magnetite alone Keywords shape, elongation value, flotation kinetics, magnetite.

Dec 1, 2013

By Frigyes Egerer, Pál Bárczy

Introduction Charles III, Holy Roman Emperor and King of the Austro-Hungarian Monarchy, established one of the first mining schools in Europe on June 22, 1735, in Selmecbanya (Schemnitz in German and Banska Stiavmica in Slovakian). The old city, built around the ancient gold mines, is shown in a contemporary engraving in Fig. 1. Charles' historical decree consisted of 13 chapters and included: the deed of foundation, the definition of grants, instruction for educational policy and curriculum, disciplinary rules, and the appointment of personnel. The first professor of the school, Samuel Mikoviny, gave his first lecture the same year, in December 1735. The 250th anniversary of the establishment of the School of Mines was celebrated Sept. 2-4, 1985, in Miskolc. It was attended by representatives of other Hungarian and of several foreign technical universities. A silver medallion (Fig. 2) was issued to commemorate the occasion and a series of lectures

Jan 6, 1986

By Richard J. Mainiero

The Bureau of Mines investigated coal-mine-type short-delay electric detonators marketed by three domestic manufacturers to determine the accuracy of delays and the probability of overlap between adjacent de- lay periods. The Winzer index was computed and compared with the probability of overlap. A close agreement between the Winzer criterion and overlap probability was demonstrated. A permissible blasting unit capable of delivering a maximum firing energy of 4.0 J and a digital oscilloscope were used to measure the delay time with an accuracy of 20.25 ms. Another oscilloscope and a pulse transformer were used to record firing current. Experimental data indicated negligible overlap probability in detonators of shorter delay periods: periods 1 to 4, which correspond to 25 to 250 ms. However, a significant probability of overlap was detected in some detonators of longer delay periods: periods 5 to 9, which cor- respond to 300 to 500 ms.

Jan 1, 1985

By M. E. Breitrick

Newmont Gold Company began full production in early 1995 at the Carlin East underground mine. The mine is currently producing at the rate of 900 tpd (1.000 stpd). for an annual production of 150.000 ounces. Approximately one hundred twenty five hourly and salary personnel are employed at the project for the estimated six-year mine life. Two mining methods are currently utilized at the mine. Longhole stoping with cemented backfill accounts for 70% of the total mine production. Conventional underhand drift and cemented fill accounts for the balance of the daily tonnage. In December 1996. Newmont purchased a new AC-Eickhoff ET-210 Roadheader. The machine went into service in mid-June of 1997 and is used in both longhole stope topcut development and cut and fill production at a rate of 225 tpd (250 stpd). The Carlin East mine is operated by Newmont Gold Company. The mine is one of four underground gold mines in production in northeastern Nevada owned by Newmont Gold.

Jan 1, 1998

By Gerardo R. F. Alvear, Alistair S. Burrows, Stanko Nikolic, James S. Edwards

"The copper ISASMELT™ process has evolved over more than a quarter of a century and can now be considered mainstream, with single furnaces producing more than 340,000 tpa of copper in matte. The next evolutionary step for the ISASMELT™ technology is to directly challenge the dominance of the Peirce-Smith converter by the implementation of a continuous copper converting process on a commercial scale. The present work describes the status of the continuous converting process – ISACONVERT™.Continuous converting has been performed successfully in pilot scale ISACONVERT™ plants, where operating results have verified the predictions of fundamental research and reinforced the underlying confidence in the design parameters. From a matte feed rate of 250 kg/hr, a calcium ferrite slag and a low-sulfur blister have been produced. Design is now complete for the first commercial application of the ISACONVERT™ process. The present paper describes the status of ISACONVERT™ by summarising results of recent pilot plant tests and describing the first commercial plant design."

Jan 1, 2009

By Ryan Sullivan, Lisa Smiley, Jewels Stover

The Westerly Storage Tunnel (WST) Project is part of Project Clean lake, the North East Ohio Regional Sewer Dist years. When completed in 2020, WST will be nearly 2 miles of 25-ft diameter tunnel 200-250 ft below ground. The storage tunnel will manage higher flow volumes, keeping stormwater out of the combined sewer system reducing overflow occurrences. Three deep shafts provide access to the tunnel at the tunnel boring machine (TBM) launch and retrieval sites, as well as a vent shaft. Support of excavation for the access shafts was constructed utilizing unreinforced concrete diaphragm walls. This innovative, value-engineered alternate design significantly reduced risks associated with conventional secant piles combined with a rib and liner plate system. Implementation of the diaphragm wall technology resulted in a water tight, continuous shaft keyed into rock. This case study examines the design, methodology, and installation challenges unique to each shaft, as well as the benefits of the final product to the overall project.

By David Stone

North American Palladium is the owner/operator of the Lac des Iles mine located 115 km north of Thunder Bay, Ontario. The mine has produced an average of 65,000 ounces of palladium since 1994. Lac des Iles is currently undergoing the first phase of a major expansion that will increase ore production from 2,400 tons per day to 15,000 tons per day. A future expansion is being contemplated for 30,000 tons per day. The current expansion will increase palladium output to 250,000 ounces per year. The mine plan for the ultimate pit results in an excavation 1 km long by 800 m wide and over 450 m deep. This makes the ultimate pit at Lac des Iles one of the ten deepest open pits in the world, and the largest in Canada. This paper outlines the geotechnical data collection and design methodology for the ultimate open pit at Lac des Iles.

May 1, 2001

The project is undertaken by Elgas Pty Ltd, a 50 per cent joint venture between AGL and BOC, to store 65 000 t of LPG in underground storage at Port Botany, NSW. The contractor, Concrete Constructions Pty Ltd, elected to use drilling and blasting techniques. The project specification called for the following works to be excavated: Access Shaft:122 m (out of 140 m total depth), 6.0 m diameter (selected by the contractor),Operation Shaft:125 m (out of 150 m total depth), 4.0 m diameter,Water Curtain Gallery:500 m (Later extended by additional 270 m), 4.0 m wide and 3.5 m high,Storage Caverns:910 m, 14.0 m wide, 11.0 m high,Top Heading:14.0 m wide, 5.5 m high,Bench:14.0 m wide, 5.5 m high,Connection Galleries:250 m, 5.5 m wide, 5.5 m high.A total of 156 000 cubm of rock to be excavated.

Jan 1, 1999

By Egonk Arriagada, Brindel Barzola, Peter Leckie, Greg Zwolak, Gilmar Guzmán, Germán Chen

Newmont’s Yanacocha operation in Peru presented an especially challenging environment for reliable cyanide measurement and control, processing 3 semi-distinct complex ore types with feed Cu ranging from below 250ppm (as CuCN) to more than 5000ppm, and feed S ranging from low to 5%, resulting in cyanide consumption from as low as 1.5 kg/t to as high as 3.1 kg/t, and gold recovery ranging from approximately 57% to about 78 % (average plant performance based on the type of ore). A literature search by the authors to identify a method for accurate cyanide determination that was also suitable for automation settled on the work of Breuer et al (2011) as a basis. Early challenges in adapting the laboratory technique for the ‘real solutions’ and the range of variability experienced in the plant are discussed, as are other operational challenges due to the complex and changing solution chemistry.

Sep 30, 2022

By John W. Lane

Climax Molybdenum Company, a Division of American Metals Climax, Inc., operated a hydrometallurgical plant* at Climax, Colorado from August 1966 through August 1968 to recover molybdenum from a mixed oxide and sulfide ore. The ore treated for this addition to the existing plant contained sufficient Molybdenite values to be mined for Molybdenite recovery alone, so that the oxidized molybdenum recovery could be regarded as a byproduct operation. Climax is located at an elevation of 11,300 feet. All process equipment, except thickeners, was enclosed in buildings. Annual snowfall is approximately 250 inches per year. Paved highways and rail service to the plant are maintained and kept open all year. Most of the employees live in the town of Leadville, which is approximately twelve miles from the plant site. The sulfide flotation plant handles 40,000 to 45,000 tons per day of ore. The mine is one of the world's largest underground mines.

Jan 1, 1971

By Homer S. Frankhouser

Materials may be dredged, processed, stored and loaded for shipment at a single site in water depths ranging from 250 to 1200 ft. Solution mining may also be accomplished in deep sea situations. And, open air subsea mines with direct surface access may be developed and worked under the ocean floor. These concepts for deep sea mining are the results of extensive testing of individual components of the proposed systems by Dravo Ocean Structures, Inc., a subsidiary of Dravo Corp. A basic structure in these systems is the articulated platform. The platform consists of a gravity- type base and a buoyant cylindrical column which is constructed at an onshore location, towed to the offshore site and installed in a matter of days without use of heavy equipment. The base is also buoyant for towing purposes. This allows for gradual flooding to the point of negative buoyancy for positioning and anchoring to the ocean floor.

Jan 1, 1971