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By Mayo D. Hersey

This problem was taken up by the Bureau of Mines as a result of the oxygen explosion at the Jefferson Physical Laboratory of Harvard University , and other similar explosions , in order to supply technical information which would serve as a basis for safety precautions in the future . At the Harvard inquiry the fact was emphasized by the Massachusetts State Chemist , Mr. Walter M. Wedger , that we do not know the limiting pressures and temperatures above which compressed oxygen and lubricating oil are capable of spontaneous explosion . The problem is also of importance to the Army and Navy and to the Bureau of Mines in connection with the hazards incurred in the use of compressed and liquified gases in the repurification of helium. In fact , the risk of fires and explosions due to traces of lubricating oil coming into contact with high pressure oxygen is of serious interest to all concerned with the manufacture and use of oxygen , a commodity which is now being produced and distributed on a rapidly increasing scale . Part of the money expended on this investigation was from Army and Navy funds . The problem was undertaken by the Bureau of Mines at the suggestion of Dr. Charles E. Munroe , Chairman of the Committee on Explosives Investigations of the National Research Council , and referred to the Pittsburgh experiment station of the bureau.

Jul 1, 1923

By I. A. Costa, Y. Fouquet, F. Barriga

"Lucky Strike and Menez Gwen are two hydrothermally active sites located along the border of the Azorean plateau, southwest of the Azores islands where the alteration processes affecting basaltic rocks are prominent (Costa et al., 2003). Here we report on a slabby brecciated rock, abundant at both Lucky Strike and Menez Gwen, composed mainly of basaltic fragments cemented by hydrothermal precipitates from warm fluid circulation system. Research reveals that hydrothermal alteration takes place mainly by replacement processes, in which silicification is dominant (Costa et al., 1997 and Costa, 2014).Petrographic observations, including scanning electron microscopy (SEM), microprobe analysis, and mass balance studies made on basaltic fragments within the breccia show that silicification is one of the main processes resulting from hydrothermal fluid circulation. This alteration process leads to complete replacement by silica, in extreme cases, forming an impermeable cap that may contribute to the formation of sub-seafloor sulphide deposits, including examples in the geological past."

Sep 1, 2014

By J. Temporal

An introduction to the conference material in this issue is given together with the issue contents list, closing remarks by its chairman Dr. J. Temporal, the list of contributors and their companies, and the information that the 26th Sir Julius Wernher memorial lecture had had to be presented by the lecturer's wife, M. Biggart, in his absence due to site problems on the Storebaelt project

Jun 16, 1905

By E. A. Brown

"IntroductionBACK IN THE nineteen-thirties, when Eldorado was a private company and was preparing to become Canada's first radium producer, the Mines Branch in Ottawa did much work on the development of chemical processes for the Port Hope refinery (1).In 1945, after the Canadian Government had taken over Eldorado for •atomic energy reasons, the Mines Branch was called upon again, this time to help out by looking into ways and means of improving ore treatment methods for the mine at Great Bear Lake. A group of technical men was assembled to devote full attention to this work, which was known as the Eldorado Project.Three years later, in 1948, the Government decided to reopen the development and operation of uranium properties to private enterprise.Since it is a function of the Mines Branch to assisit private development of Canadian mineral resources, this new uranium policy made it important for the Branch to be in a position where it could provide up-to-date services, technical assistance, and information relating to treatment of radioactive ores, mineralogy of radioactive ores, and assay methods for radioactive ores.At the same time, .because of the demand for increased uranium production, lower grade ores had definitely come into the picture, ores that might be of decidedly lower grade than, say, Eldorado pitchblende, and of entirely different nature."

Jan 1, 1953

By S. H. E. Phillips

This report describes the initial feasibility, the development and the field demonstration of a system for shaft sinking employing a high energy mechanical impact rock breaker and a compatible muck disposal system. The increased shaft sinking rates, decreased costs and improved safety conditions obtainable by the elimination of the less efficient conventional drill-blast-muck cycles are discussed. Four shaft sinking concepts utilizing the impact rock breaker in various shaft configurations are developed and the field demonstration in a rectangular shaft is described. The progress achieved, the problems and their remedies and the proposed modifications to improve the machine are described.

Jan 1, 1978

By D. A. Norrgran, J. A. Wernham, D. E. Walsh

A qualitative test program was sponsored jointly by the University of Alaska and Eriez Magnetics, in order to study placer gold nugget recovery using an eddy-current separator. Various gold nuggets from Alaska, ranging from 6.4 mm to 63.5 mm in size, were tested. All testing was performed using an Eriez Laboratory ESC, Model REA, fitted with 2000 gauss, surface field strength magnetic rotor. The belt speed was set to 91 meters per minute and the rotor speed was set to 2500 rpm in the forward direction. The splitter was adjusted to just reject the largest pieces of rock that measured an average 76 mm x102 mm x 127 mm. Based on the results of this limited test work, it can be recommended to placer gold mine operators, that Eriez Magnetics ECS technology is a viable and practical concentration technology for coarse gold recovery. Silver and platinum were also tested.

Jan 1, 2003

By J. A. Lombardi

Acid-Minesite-Solutions (AMS) are defined as copper-containing pit lake, tailing pond, acid-mine-drainage, and heap and waste dump irrigation solutions. All of these solutions are characterized by copper, acid and water contents that have value as individual commodities. HW Process Technologies, Inc. (HWPT) has developed nano- and hyper-filtration membrane methods for the separation of copper and other base metals, acid and water from AMS. These treatments are collectively called HWPT?s Engineered Membrane Separation® (EMS®) systems. The EMS® method of copper recovery produces small volumes of higher-concentration copper solution from large-volume, copper-dilute AMS. A case study of the 4,000 gpm Cananea EMS®-AMS plant for the recovery of copper from an acid-pit-lake resource is described. The EMS® method of copper removal from AMD and tails pond waters has been bench-scale demonstrated and are described, complete with projected budgetary capital and operating costs. Additional treatments for the recovery of sulfuric acid and high-quality water from the permeate (membrane passing) waters for the above-described AMS treatments are presented, with budgetary capital and operating cost estimates. [ ]

Jan 1, 2009

By B. Caro Vargas

The Toulon Tunnel project is a key component of the highway corridor on the French Riviera between Marseille and Nice and is a fundamental transportation infrastructure for the region. The first design studies started in the 1960s. The tunnel project is comprised of two separate tunnels: south and north. The north tunnel was built between 1992 and 2002 after 10 years of difficult construction. On March 15, 1996, for example, a collapse of the tunnel in the Marchand area generated a sinkhole in the city center, causing a 20-month delay. The south tunnel alignment runs parallel to the north tunnel below Toulon?s historical downtown at a depth of 20 to 40 m (65 to 131 ft) with some areas with less than 10 m (32 ft) of cover. The risk management program was studied to be a state of the art program in urban tunneling construction.

Jan 1, 2012

By Pavel Vasak

The Laurentian University Virtual Reality Laboratory (VRL) has provided a unique platform for the development and testing of novel seismic and microseismic data processing and visualization technology. In collaboration with Vale?s Creighton Mine, the technology was implemented at the mine site and consists of a VRL system and site calibrated Seismic Excavation Hazard Map (SEHM) software. The SEHM was developed as a practical solution for the mine operator to identify areas of elevated, active rock mass damage processes caused by recent mining activity. This paper is a pictorial representation of the 3D stereoscopic demonstration of the Creighton Mine seismic data distribution and interpreted SEHM for the first quarter of 2009. A live demonstration is scheduled at the Laurentian University VRL as one of the conference field trips. The demonstration highlights the technology transfer of research concepts into a near-real-time excavation hazard system that utilizes the key aspects of virtual reality technology; the ability to integrate large datasets (geology, mine excavation, (seismic) monitoring data, production scheduling, stress model, etc.); the ability to manipulate and visualize large datasets in both space and in time (mining sequence); and the ability to review the datasets by a group of experts in an immersive (3D stereoscopic), collaborative environment to better understand the processes and context of the mining-induced seismicity and evaluate potential risks to the mining operation.

Oct 1, 2010

By J. H. E. Jeffes, C. Diaz

The heat balance and chemical equilibria involved in the production of blister copper from a chalcopyrite concentrate in a single operation are examined. It appears that two stages—one oxidising and one reducing—will be required. The analysis indicates that on thermal grounds the process is possible with a dry, high-grade chalcopyrite concentrate, if oxygen enrichment to about 30 per cent is used, but that copper losses in the slag will be serious and will require a secondary recovery operation. More extensive data on the activities of copper oxide in slags are required to elucidate this point more effectively

Dec 1, 1971

By Steve Kral

The mining industry is no stranger to hard times. Throughout its history, the industry has faced the ups and downs of commodity prices, difficult-to-mine-and-process ore bodies, labor issues and other problems. Throughout it all, though, the mining industry continues to provide the materials needed for society —even in the face of attacks by those who seek to cripple the industry or have it go away. The reason the mining industry survives, of course, is that mankind requires the products the industry produces. And, in recent decades, the industry has developed new technologies and improved on existing ones to produce those products in environmentally sound ways. At the same time, the economic benefits have been enormous to communities throughout the world where mining takes place.

Jan 1, 2002

By Roger S. Jackson

"This study interprets vibrations produced by single underground shots, recorded on surface by 135 digital seismographs laid out in four linear arrays. Several vibration anomalies were observed and are investigated. A novel method of displaying the blast-induced vibration iso-contour data relative to the three-dimensional representations of the geological rock units and structures leads to the following interpretations:• The identified faults commonly dampen or amplify vibrations, on the evidence of the peak particle velocity,• Strong anisotropy of geologic formations produces different vibration attenuation in the various directions of interest,• Low-vibration “depressions” can be related to the presence of faults, and• Higher vibration levels than expected based on ‘scaled-distance’ principles are observed close to intersecting faults.The interpretations from this study document a better understanding of the geotechnical influences on blast induced stress wave propagation in a geologically complex area. The practical benefit of this understanding is better control of surface vibrations, experienced from underground mining activities."

Jan 1, 2010

By P. A. Olubambi1

Representative samples of the hydrothermal vein deposits of the bulk complex sulphide ore deposit, 10 km south of Ishiagu, in Ebonyin State, South Eastern part of Nigeria were collected from two small scale mining companies. The samples were mixed and successively crushed in a jaw crusher and cone crusher, and ground in a rod mill. Characterization was carried out with SEM, EDX, XRD, XRF and ICP-OES. Mineralogical analysis revealed the presence of sphalerite, galena, siderite, pyrite, quartz and chalcopyrite. X-ray Diffractometry showed that sphalerite mineral in the ore occurs as sphalerite ferrous with varied percentage of Zn and Fe within the various sizes while chalcopyrite occurs as a chalcopyrite group mineral with chemical formula Cu2MnSnS4. Results of the elemental analysis showed variations in elemental composition within the different sizes.

Jan 1, 2006

By P. J. Doig

The LCLS project at SLAC will allow new insights into material properties, chemical reactions and biological processes. The project includes half a mile of new underground construction. Excavation in weathered rock is by NATM, using AM 50 roadheaders. Construction began in 2006 and is expected to be completed in 2008. This paper details the construction of the tunnels and cavern on the project.

Jan 1, 2008

By Lon Santis, Dale Ramsey

The use of aircraft to support blasting operations in mines, quarries and construction sites goes back to the early days of aviation. Invaluable at times, aircraft use has been limited by cost, the unpredictability of weather impacts and other factors. Recently several technologies have matured to open up a new way to acquire aerial data with unmanned aircraft systems (UAS), commonly called drones. Equally important, the U.S. Federal Aviation Administration has recently implemented an exemption process and rulemaking to implement the commercial use of UAS into the United States’ National Airspace. The skies are opening for many applications of UAS. The most notable may be photogrammetry, which is the science of making measurements from photographs, especially for determining the exact positions of surface points.

Jan 1, 2016

By James D. Nickerson

Thee Brightwater water treatment facilities, currently scheduled to be completed in 2010 and begin operating in 2011, will serve the northern part of King County, WA. The facility includes a new treatment plant and extensive conveyance system consisting of more than 21 km (13 miles) of influent and effluent conveyance tunnels and five portals. The majority of the conveyance system tunnels are mined by tunnel boring machines (TBM) and microtunnel boring machines (MTBM). Tunnel and portal construction is divided into three main contracts. The Ballinger Way receiving portal, constructed under the central tunnel contract, is the terminus for the BT-3 leg of the central contract and the BT-4 terminus of the west contract. The shaft has a 7.3-m (24-ft) finished inside diameter (ID) to accommodate removal of the central project TBM and the west contract TBM and extends to a depth of 66 m (216 ft) below grade through a complex and challenging soil profile characterized by multiple ground water tables. Vinci Grand Projects/Parsons/Frontier-Kemper Constructors (VCFK) was the joint venture team for the Ballinger Way portal. Frontier-Kemper was responsible for the shaft sinking. VCFK evaluated either slurry wall techniques or ground freezing for earth support during excavation of the portal and liner installation. The selection process took into account the vertical depth, cost, past practice, geology, water tables and a 9-m- (30-ft-) thick zone of contaminated soil at the top of the shaft. Ground freezing, which would also act as a hydraulic barrier, was deemed the better option for this project. The contract was awarded to New Jersey-based geotechnical contractor Moretrench. Typically, frozen walls, by design, key into an underlying cutoff. At the Ballinger Way portal, however, the [ ] freeze bottomed out in a substantially thick stratum consisting of predominantly clay, but with some inclusions of permeable soil that indicated significant ground water pressures. To ensure stable conditions at the bottom of the shaft, Moretrench, which also specializes in dewatering, designed and installed a perimeter array of deep wells to temporarily depressurize the permeable soils. The movement of ground water generated by pressure

Jan 1, 2009

Bioleaching Metals from Waste Printed Circuit Boards and the Shapes of Microorganisms

Sep 13, 2010

By G. H. Lind

New South Wales has a successful history of pillar extraction stretching back more than 60 years. Various methods of pillar extraction ranging from the rib pillar methods (such as the Wongawilli system) to the more recent pillar stripping techniques (similar to those used in the USA) are discussed in this paper. These discussions are based on the experiences of the author stemming from a recent research tour of seven underground pillar extraction operations in New South Wales as part of the Coaltech 2020 collaborative research initiative. Some operational issues of each site visited are presented before some general comments pertaining to the overall success of pillar extraction in New South Wales are discussed. Generally pillar extraction in New South Wales is on the decline in favour of longwalling. However, the pillar extraction that is conducted is done so along specific guidelines to ensure their success, and these are also discussed.

Jan 1, 2002

By Met B. E

The increasing pace of modern mining makes constantly greater demands upon the several contributing departments of rock breaking and transport, and rock-drilling, as the spearhead of attack, has received a great deal of attention with respect to both machines and steels. By a series of mechanical improvements, combined with the application of selected heat-treated alloy steels, the rock-drill has now been developed into a machine capable of rapid drilling and long service under severe working conditions. As a factoryproduct made under strict metallurgical control it is as foolproof as, say, the modern automobile, and, like its prototype, it can be kept in efficient operation by a minor amount of attention during use and by periodical adjustments and replacements.The same cannot be said, unfortunately, of the drills with which the machine is supplied; in conventional mine-shop practice these are made of the best tool steel shaped and heat-treated under the poorest of metallurgical conditions.The crudities of steel-shop practice have, in fact, always prevented the full exploitation of the steels available at any time, and even at the present day the general standard of treatment offers a contrast with the quality of the steels which moves the metallurgist to amusement, despondency or outrage, according to his temperament. Nevertheless, the tendency persists to meet the increasing demands of the rock-drill primarily by the use of still better steels, and secondarily by improvement, of the steel-shop practice. Athird type of development is the introduction of factorymade tools in the form of detachable bits and rods. It is proposed in this paper to deal with these three aspects of the recent developments in rock-drilling.*Re-written from a lecturette given during the First Ordinary Meeting, 1936.

Jan 1, 1936

By Peter Middendorp

Pile foundations are widely applied in the Netherlands because of the soft soil conditions. One of the popular pile types are cast-in-situ piles, which have to be integrity tested to get accepted. Integrity testing has been applied for more than 30 years, with the number of integrity test performed nowadays exceeding 400,000 per year and subsequently there is a substantial amount of practical experience with this testing method. This paper will deal with some basics of integrity testing and describe some of the techniques that have been adopted in the Dutch pile testing practice, like detection of pile head defects with a spike type hammer pulse, and the site average or pile group average for the qualitative interpretation of measured signals.

Jan 1, 2006