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By Jay Hilary Kelley

A ventilation system is described using dual aircourses: one zone occupied by working personnel, the other at the active working face. The two zones are separated by a partition or Shroud. The occupied zone to the rear of the face zone is ventilated adequately but with considerably less air because little gas, dust, or fumes are present. The face excavating zone is sealed and maintained at slightly more negative pressure preventing dust and gas generating from within to escape. Explosive mixtures within the face zone is rendered non-explosive by the introduction of inert gas therein. Each zone is vented separately to the outside of the mine. Because less total quantity of air is required for human breathing, etc, the total ventilation system can be drastically reduced in tan capacity, development entries, and air shafts, -- a great savings in costs.

Jan 1, 1991

By D. L. Jones, S. Knoerr, J. Mansanti

The Buckhorn Mine in Nevada currently treats oxide ore using heap leach methods, but exploration has identified sulphide reserves which are refractory in nature. Preliminary testwork was conducted on the sulphide material to screen potential pre-cyanidation treatment methods. Processes evaluated included pressure oxidation, biological oxidation, nitric acid oxidation and roasting. An initial economic and process analysis of the results concluded that roasting was the only viable process, and only if the roaster off-gases were converted to soleable sulphuric acid. Further economic analysis indicated that roasting of the whole ore was more attractive than pre-concentrating by flotation, followed by roasting of the concentrate. These results were generalized to show that for high sulphur ore a roaster/acid plant combination is more attractive that either of the other options, ie. pressure leaching or bioleaching, provided the by-product acid is soleable.

Jan 1, 1990

By GRANT COLLIGAN, BROCK O’KELLEY, Corby Anderson

With the world’s ever-growing push to expand technological capabilities, the need for specialized materials including rare earth elements has exploded. One source of rare earths found in the United States is bastnaesite, a rare-earth-bearing fluorocarbonate, mined at the Mountain Pass Mine in California. To increase production, it has been essential to optimize existing processes and create new ones to capture current reserves. This paper presents the results of a research program conducted to expand the understanding of the bastnaesite leaching system. With the help of prior knowledge and thermodynamic calculations, a novel single-stage hydrochloric acid leach system was created to optimize the extraction of rare earths from bastnaesite. Historically, this extraction has entailed the use of a two-stage leach system involving a high-temperature hydrochloric acid leach followed by a caustic crack. We ran a series of single-stage leach experiments by reacting locked-cycle flotation concentrate with hydrochloric acid to test common leaching parameters. The results of these single-stage tests showed significantly higher rare-earth recoveries than the reported recoveries of the historic two-stage caustic crack processes, all while decreasing the number and amount of reagents needed.

Feb 1, 2023

Strategic Branding ? In 2006 Explore for More was created ? By industry, for industry ? Cohesive approach to career attraction ? Defines industry and employers of choice Career Kits ? Positive impression of mining: ? before seeing the brochure 31% ? after seeing the brochure 83% ? Likely to consider a career in mining: ? before seeing the brochure 12% ? after seeing the brochure 23% MARS ? Mining Attraction, Recruitment, and Retention Strategy (2007-2010) ? Attract, recruit and retain a skilled workforce ? Increase participation of under-represented groups ? Dispel myths and misconceptions of the mining industry ? Inform and educate Canadians of career opportunities ? Promote and build upon industry best practices in workforce planning

May 1, 2009

By E Hawkins, S Sheldon

Block caving is becoming a more widely adopted mining method allowing for underground massive low grade orebodies to be extracted economically. Underbreak during cave propagation is difficult to predict in terms of recovery and is not well-researched due to the small number of caving operations. During mining of E26 Lift 2 (E26L2) block cave at CMOC Northparkes Mines, a wedge of high grade material failed to cave, even with the assistance of preconditioning and subsequent attempts to induce caving. The ultimate solution for recovery of the uncaved wedge was the establishment of the E26 sublevel cave (SLC), which commenced mining in 2015, with production following in 2016. The SLC provides approximately 1Mtpa to supplement the lowering grade of the current E48 block cave feed. Applying the sublevel caving methodology to recover block cave underbreak has proven challenging. The impact of the caving stresses and preconditioning of the wedge have caused production limitations requiring continual remediation throughout production of the E26 SLC. The dependence on remediation work created a roadblock to implementing precharging as the prevalence of brow loss raised concerns over the inability to hook up the charged ring. In 2018, a wireless initiation trial was completed in the E26 SLC over 24 rings. The trial showed that precharging was achievable in this environment and greatly improved the safety of charge up personnel.

Mar 15, 2021

By A. Martikainen

Field tests concerning a fog mesh method for fog removal are discussed. The first tests were performed at the Pyhäsalmi Mine, Finland. As this study gave promising results, further studies were completed at the Orivesi Mine. The results of these most recent field tests are presented and the two studies are compared. The Orivesi test set consisted of four materials. These included air filter fabric, fibrous filter fabric, a plastic greenhouse mesh, and an aluminium mosquito net. The variation of the Orivesi results was more noticeable than what was found previously. The best fog removal effect of all tests was achieved with the aluminium mosquito net, while the plastic green-house mesh performed worst. The humidity reduction by aluminium net was more profound than any of its precedents. More mesh materials will be tested in the near future.

Jan 1, 2007

By A Misra

In pursuit of solving the development rate problem the coal industry has investigated various development systems. While all the systems may improve the development rate they may not necessarily he cost effective. This paper carries out an economic analysis by developing cost models for present and future development systems for retreating longwall faces with particular reference to Australian longwalls. A critical cost analysis of various development systems is presented by taking into consideration all the costs associated with development systems. The costs have been divided into equipment, face and panel services, belt and structure, wages, roof and rib support, ventilation, consumables, power and maintenance. The annualised cost of various equipment has been obtained on the basis of depreciation rates prescribed by the Australian Taxation Office.

Jan 11, 1996

By Adam Gesing, Ron Dalton, Richard Wolanski, Larry Berry, Christopher Stewart

As the quantity of aluminum recovered from shredder scrap continues to increase, together with increased content of aluminum in automobiles, so does the economic incentive to further upgrade shredder scrap. This upgrade will be done by sorting and recovering the aluminum by specific usable alloy compositions. The metal recycling industry infrastructure needed to deal with the increased aluminum scrap supply already exists. It is an inverted pyramid structure that in North America comprises: 3000 scrap collection yards, 200 shredders, a dozen sink-float plants and one heavy metal sorting operation. The technology for upgrading aluminum sorted from shredder scrap is already either in industrial use or in the final stages of pilot plant development. However, the current automotive aluminum recycling infrastructure will need to adjust to deal with higher volumes of the metal from aluminum-intensive vehicles that will be appearing in shredder scrap -20 years from now.

Jan 1, 2000

By Osvaldo Valdez, Matteo Bertoni, Aem Ragy

The East St. Louis Deep Cutoff Wall project is located in the area of East St. Louis, Illinois, across the Mississippi River from the city of St. Louis, Missouri, along the left descending bank of the river. The project is a fundamental part of the U.S. Army Corps of Engineers' (USACE) effort to rehabilitate and secure the aging East St. Louis levee system that provides flood protection to approxi- mately 250,000 residents and more than $4.5 billion in economic value. The project was devised and de- signed by USACE as a cutoff wall to be installed in the Metro East Sanitary District levee segment, one of the levee segments that form the East St. Louis system. The contract for the construc- tion of the cutoff wall was awarded in November 2019 to Bauer Foundation, the American subsidiary of the Bauer Group.

Sep 1, 2023

By G. V. Sirianni, G. E. Viens, R. A. Campbell, G. N. Banks, R. L. Sachdeva

"A combined shaft-electric furnace for the smelting of ores and the melting of metallized iron pellets is being developed. The materials are preheated, and in some cases pre-reduced, in the shaft before being transferred to the electric furnace, where melting or smelting is completed. It has been demonstrated that this combination of equipment will enable much of the relatively expensive electrical energy to be replaced by cheaper energy in the form of oil or natural gas, and preliminary experiments indicate that the total energy requirements for a melting or smelting operation are significantly reduced. Projections based on results obtained from the preliminary experiments indicate that further improvements will be possible when certain modifications to the equipment are completed."

Jan 1, 1968

Silica and limestone fluxing levels in copper smelting slags were studied. Copper concentrates with flux additions were smelted to matte (55.5 per cent Cu) and slag in a pilot scale submerged combustion furnace.Results indicated that oxidic and sulphidic copper levels in slags were minimised with a slag Si02 level of 36 per cent and a SiO2/CaO ratio of 5.5. Total copper losses in slags were 0.6 per cent under these conditions.To produce the desired slag chemistry, additions of bulk silica and limestone to copper concentrates of fluctuating grades were predicted numerically. The method employed the solution of two simultaneous equations, each respectively for silica and limestone calculations.The predicted flux additions were applied in a further series of tests and the resultant stages were found to be satisfactory. The method is applicable to smelting 'operations which employ two flux bins, with weigh feeders, so that slag chemistry may be controlled with the flux/concentrate feed mix.

Jan 1, 1985

By Toshio Kurikami, Charles A. Brockmiller, John E. FitzSimmons

In the manufacture of sulfuric acid from SO2 bearing gases, the presence of mercury vapor in the gases may lead to unacceptably high mercury levels in product acid. Anticipating inception of regulations requiring low mercury acid, St. Joe Minerals Corporation and Toho Zinc Company, Ltd. independently developed new mercury removal technology. The processes may be used individually or in combination, depending upon the mercury content of the SO2 gases and the required mercury level in acid, for efficient control of maximum mercury levels in sulfuric acid. The St. Joe B Process removes mercury from roaster off-gas streams, while Toho’s NAK Process precipitates Hg from concentrated sulfuric acid. The combined process is commercially operated at St. Joe's zinc smelter in Monaca, Pennsylvania, and the NAK Process at Toho’s Chigirishima lead smelter and Onahama zinc roasting plant in Japan. Product acid mercury levels of 0.5 mg/kg are economically achieved.

Jan 1, 1976

By B. Denby, R. Hollands

Mine information is often multi-disciplinary, dynamic and spatially complex. Different departments use the same data in many different ways, information changes over time and mines change their shape continuously. Earthworks InTouch is a radical VR-based system developed by AIMS Solutions and marketed by Earthworks, which provides a rapid and intuitive interface to a wide range of mine information. VR is used to provide an interactive and visually accurate, dynamic 3D model of the mine workings and equipment operating in the mine. Individual objects in the mine can be linked to external applications that provide up-to-date and context sensitive information. Equipment movement can be simulated or tied in to real-time survey from GPS systems for example or excavator productivity data can be extracted from a production database. The paper will highlight the major advantages of using such a VR interface to access valuable and time sensitive information.

Jan 1, 2002

By Linda L. Chasko, Charles P. Lazzara, Ronald S. (deceased) Conti, William J. Wiehagen

Fire has long been a concern for underground mine workers. A mine fire can occur at any time and can result in a partial or total evacuation of mine personnel and the loss of lives. Fires can grow rapidly. Time is the critical element. Prompt detection, timely and accurate warnings to those potentially affected, and a proficient response by underground miners can have a tremendous impact on the social and economic consequence of a small underground fire. Fire preparedness and response have components of technology and people. These components can work synergistically to reduce the time it takes to bring the system back in balance. This report deals with the preparedness of miners to respond to underground mine fires. It is intended to aid the mining industry in understanding the various roles of emergency responders and the training techniques used to increase their skill levels. The report also presents a technology overview to assist in effective response to mine fires.

Jan 12, 2005

Ore deposit modelling is becoming an increasingly accepted tool in mineral exploration. Successful models have already been proposed for several ore deposits of base metals and gold, but tin has so far received comparatively little attention, perhaps because of an excessive preoccupatioi with alluvial operations. This situation is rapidly changing and some of the world's most profitable and newly commissioned tin mines are large, primary tin deposits. Some basic principles of ore deposit modelling are briefly reviewed and the fallacy of an excessive reliance on grade tonnage diagrams based on the tin industry worldwide is discussed. The four proposed models and submodels of large, hard-rock, tin deposits focus on basic concepts such as the spatial relationship with "tin granites", depth of emplacement and the level of erosion. General concepts are drawn. The modelling of large primary tin deposits is reviewed not only in its geological and exploration aspects but also in its mining and economic implications.

Jan 1, 1986

By Verya Nasri

The use of a single tunnel boring machine (TBM) tunnel of approximately 12 to 13 m (40 ft to 43 ft) diameter for transit systems to house both light rail or subway tracks in a stacked configuration is an advanced concept that allows significant savings in construction cost and time while reducing, to a large extent, the negative effects on the environment. This solution, similar to the recently completed Barcelona Metro Line 9, integrates station platforms, train storages, crossovers, bypass tracks, ancillary areas and utility corridors inside a single tunnel. Each of the underground stations consist of a cut-and-cover entrance structure and ventilation shafts, that also serve as emergency exits. The excavations for the station structures and shafts can be done on one side of the street with nominal impact on traffic and utilities.

Jan 1, 2010

By Franco Oboni, Iain G. Bruce

The design of tailings containment structures relies on well-understood engineering methods being applied consistently. Unfortunately, not all facilities are designed or managed to the same level of competency. To standardize procedures, the Mining Association of Canada (MAC, 1998) prepared a “Guide to Tailings Management.” It recommended review of designs and an assessment of the risks associated with tailings impoundments be implemented during all phases of amine life. This paper describes how the quantitative risk assessment (QRA) process can be used to define risks associated with the design, construction and operation of a tailings management facility. And it discusses how, once the risk tolerability curves (RTC) are defined for a project, they can assist the risk management (RM) process.

Jan 1, 2002

By E. G. Leonardon

The question of geophysical prospecting is one that is beginning to occupy a pre-eminent place in the minds of those actively concerned in the discovery and exploitation of ore deposits. This is in marked contrast to the reception accorded such ideas when the Junior author, six and a half years ago, began introducing electrical prospectii1g to the mining fraternity on this continent. Happily, the mention of geophysics no longer evokes the sceptical and pitying smiles that it did in those days. A little reflection will show that modern geophysical methods are merely a logical development from pre-existing technique. In the study of geological problems, is it not logical to use all possible physical properties of matter? The study of crystal form and cleavage, the examination of thin sections of minerals by means of polarized light or ordinary light, in fact, utilize physical properties of minerals for the benefit of the geologist. These are, of course, laboratory methods, and the extension of the study of similar properties into field work was inevitable. This began with the magnetometric surveys, used as early as 1760 in New Jersey to locate iron ores. Eighty-four years later, John Locke's work in the United States resulted in pointing out relationships between the terrestrial magnetic field and main tectonic features of the earth's crust.

Jan 1, 1928

By D J. Black

Ventilation modelling is used to evaluate ventilation system performance. This paper describes modelling to assess potential changes to a single entry longwall ventilation circuit to improve ventilation and gas management. The longwall panel is extracting a 215 metre face in a 1.5 metre coal seam at a depth of 900 to 1000 metres below surface. The 1.5 metre B seam is located approximately 25 metres below the main 3.0 metre A seam and the gas content of both coal seams is approximately 20 to 25 m3/t. The B seam is extracted prior to the A seam and the mine relies on fracturing of the overlying strata to induce gas emission from the A seam to reduce the gas content prior to mining. Longwall operations in the B seam are constrained by limited ventilation and high gas emissions. Due in part to statutory limits on gas concentration and air velocity, the average longwall production rate is approximately 700 t per day.Gate roads in the B seam are single entry, developed using road headers and supported with steel arches. Additional timber cog support is installed to reduce roadway closure from abutment loading. Due to the slow advance of gate road development, mine management were reluctant to consider significant mine design changes, such as two heading gate roads; therefore, the investigation focused on determining the extent to which ventilation and gas emission impacted on longwall production performance, while recommending short-term, low-cost actions to improve ventilation and gas management to support increased longwall production.CITATION:Black, D J, 2017. Application of modelling to improve ventilation and gas management in a single-entry longwall panel, in Proceedings Australian Mine Vent Conference 2017, pp 239–244 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

Innovative Technology for Optimised Thickening Sedimentation

Sep 13, 2010