Search Documents

Attempts to rationalise the geological environment of nickel sulphide deposits associated with Archaean ultrabasic rocks has produced much speculation as to the origin of the sulphides and the relative importance of geochemical, mineralogical, textural and structural characteristics of the host rocks. From an economic viewpoint the object of such work is to establish geological criteria which can be used as an exploration guide. Exploration procedure for nickel sulphide mineralisation of the 'Kambalda type' (Hudson, 1972), which occurs at or near the basal contact of Archaean ultramafic flow units and lenses consisted of geological mapping, surface prospecting with soil sampling and rock geochemistry.

Jan 1, 1987

By Ray Brainard

Treated effluent from the Clean Water Coalition (CWC) member agencies is currently discharged at an annual average rate of 6,570 l/s into the Las Vegas Wash, and is increasing annually. As the effluent flow increases, the nutrient loading of the treated effluent will approach the maximum limits allowed under the current regulations. To manage this flow while maintaining water quality in Lake Mead, the CWC is implementing a 44-km-long conveyance system. This paper discusses the geological and geotechnical aspects of the 13.4-km-long tunneled section through the River Mountains and their effect on design. The tunnel alignment traverses a heterogeneous package of volcanic and sedimentary rocks exhibiting widely variable rock conditions.

Jan 1, 2008

By Dakota D. Faulkner

Cable bolts have been very effective in mine ground control. Non-tensioned and tensioned cable bolts are now used for both primary and supplemental bolting (Suder, 2001; Mirabile, 2010). In the United States, cable bolts are typically installed in either 1 or 1-3/8 in. (25 or 35 mm) diameter drill holes and, if point anchored only, are utilized with 4 - 5 equivalent feet (1.2 - 1.5 m) of resin. Cable bolts can be tensioned by various methods such as using an expansion shell mounted on the cable or post-tensioned with a hydraulic cable tensioning unit. In recent years there has been a desire to completely encapsulate the cable bolt for corrosion protection. Fully encapsulating a cable bolt with traditional resins can be very difficult. Keystone Mining Services, LLC (KMS) and Jennmar Corporation have developed a new cable bolt that can be fully encapsulated during installation or post-installation with polyurethane (PUR). The Fully-Grouted Cable Bolt (FGCB)* is equipped with a special head that allows the injection of PUR up through the cable bolt head and cable strands, completely encapsulating the cable and filling the drill hole. Although the FGCB was initially developed to fully encapsulate the cable for corrosion protection, it was also found that by modifying the cable bolt head and injection pressure, PUR could be injected into cracks and fissures of the strata to stabilize the roof. This paper details the development of this system and three underground applications under different ground conditions.

Jan 1, 2012

1.0 SCOPE AND REGULATIONS 1.1 This specification covers the minimum requirements for material handling and associated equipment including design and materials. 1.2 This specification requires compliance with all federal, state, local laws and regulations which may be applicable including the Occupational Safety and Health Act, Construction Safety Act as well as rules, regulations and standards of the Secretary of Labor.

Jan 1, 1979

By O. P. Garg

"The Iron Ore Company of Canada (IOC) operations in Labrador and Quebec, in Canada, is among the largest openpit mining complexes on a world wide basis. Since the 1981-82 recession, IOC has embarked on a comprehensive cost reduction and productivity improvement program in order to survive in the world iron ore market.This paper will outline the approach used in prioritizing the cost reduction items.IntroductionMuch of the mining industry in North America is in a crisis state. Most producers are operating at production levels well below capacity, some have been merged or sold, while others have been mothballed or closed permanently. For many of us still operating, the future is uncertain. Despite the many cutbacks and closures, there is still an abundant supply of minerals in the world market and there is almost no hope for any relief on price pressures on most mineral commodities in the near future. The Iron Ore Company of Canada (IOC) operates an iron ore mine, a concentrator and a pellet plant known as the Carol Project located in Labrador City, Newfoundland. This concentrator and the pellet plant have the annual capacity to produce 20 million and 10 million tons respectively. A company owned and operated railway links this operation with the dock terminal facilities in Sept-Iles, Quebec.In the past decade the Iron Ore Company of Canada has been one of the largest producers of iron ore products in the world. Its pellets and concentrates as well as natural ores were sold in North America, Europe and the Far East. In 1981-82, sales, particularly in North America, went into a serious decline. For almost 30 years, the gospel IOC preached to employees was ""production, production!"" There were many innovations, and millions of dollars were spent on the biggest and best equipment, on research and development, on training and developing employees."

Jan 1, 1987

By Aparup Chattopadhyay, Barun K. Gorain

"Porphyry copper deposits are the most important source of copper and also gold within the orogenic belts. These deposits are characterized by low grade copper ore (0.2% to 1% copper) and host precious metals like gold, silver and platinum. A characterization tool has been developed for complex porphyry type copper-gold deposits with an aim to quantify copper and precious metal deportment. This quantification is a challenging task due to low grades and also due to the presence of both visible and invisible precious metal content in different sulphide and non-sulphide phases. Studies were initiated on various complex ore deposits and also on samples representing various processing streams such as flotation and leach products. This paper presents the development of a systematic approach to diagnostic metallurgy using state-of-the-art optical and automated mineralogy, micro-probe, dynamic SIMS and TOF-SIMS analysis for quantification of invisible and visible precious metals content in various species. The relevance of this characterization to metallurgy will also be briefly discussed in this paper.INTRODUCTIONA novel characterization tool has been developed for double refractory gold ores and complex copper-gold ores using state-of-the-art technology for quantitative gold and copper deportment study. The characterization of these ores is a challenging task due to low copper and gold grades in ores, presence of both primary and secondary copper sulphide phases and variable proportion of visible and invisible gold in different sulphides phases (pyrite, chalcopyrite, chalcocite and bornite) and iron oxide phases (magnetite, hematite and goethite). A study was initiated on various ore deposits and also on samples representing various processing streams of pilot plant batches such as flotation concentrates and tailings. This paper attempts to discuss the deportment characterization methodology through presenting results from investigations on four samples from a flotation circuit viz, Feed, Final concentrate, Cleaner Scavenger Tail and Rougher Tail samples. These four samples represent the key streams for a typical copper-gold flotation flow sheet. The key objective of this investigation was to identify and quantify visible and invisible gold along with understanding the morphology and liberation of gold associated with various sulphides, Fe- Oxides and non-sulphide gangue species. In addition, the aim of this study was also to relate this mineralogical and gold deportment information to metallurgical performance."

Jan 1, 2013

By W. Lee Daniels

Significant deposits (> 4,000 ha) of heavy mineral sands were discovered in the USA Coastal Plain of Virginia and North Carolina in 1989. The majority of these lands support highly productive row crop agriculture, and the development of restoration protocols that would return these lands to agricultural use was deemed to be critical to the long term sustainability of mining operations. Virginia Tech worked closely with all stakeholders to develop appropriate restoration protocols and to coordinate their implementation. Full-scale mining operations at the Old Hickory Project in Virginia were initiated in 1997 by Iluka Resources Inc., and restoration protocols have continued to evolve in response to a variety of economic, technical, and social issues. Approximately 750 ha of land are in various phases of backfilling and final reclamation. Return of these lands to agricultural row-crop production has been complicated by lateral variability in mine soil physical conditions, excessive compaction, and limited topsoil return. However, within the past two years, a series of tailings deposition and soil reconstruction practices have been developed and implemented that significantly improve post-mining soil productivity. Deep ripping and appropriate use of organic soil amendments have been particularly effective at restoring post-mining soil productivity.

Jan 1, 2005

By Darcey Baker

Quarry Blasting is usually boring, and that is how we like it. By this, boring means routine, straightforward, meat and potatoes blasting. Quarries typically will not utilize cast blasting, coyote tunnels, or any of the other more spectacular blasting techniques – just plain, old day-in and day-out quarry production and possibly overburden blasting. Differences in material characteristics, mining method, equipment availability, and target markets all play a part in determining the blasting procedures employed at any given location. However, variables exist everywhere and with foresight and planning, effects of tangible variables can be minimized. Variables caused by geology, weather, neighbors, or limitations caused by major plant or mobile equipment are, generally speaking, intangible; and leave the operator with finite options to improve or modify blasting procedures.

Jan 1, 2009

By J. D. Ramsdell

To obtain information on the effects of cobalt on microstructure and tensile properties of titanium-vanadium-cobalt alloys, the composition ranges of 4 to 16 percent vanadium with 1 to 4 percent cobalt have been studied. The beta phase was not completely retained with vanadium additions up to 16 weight-percent or in the same alloys containing up to 4 percent cobalt.

Jan 1, 1960

By Jochen Petersen, David G. Dixon

"Although heap leaching may be perceived as a somewhat low-tech route for the extraction of low-grade minerals, the underlying physical, chemical and biological processes are in fact extremely complex. There has been increased interest in heap leaching of sulphide minerals in recent years with the advent of controlled bio-heap leaching, and the need to mine more marginal ore deposits.A detailed investigation into the dynamics of heap leach processes has provided much insight into the underlying complexities, and has led to the development of a sophisticated modelling tool, HeapSim. Some of the sub-processes that are modelled include mineral kinetics, particle size effects, bacterial growth, oxidation and adsorption, gas adsorption, pore diffusion, bulk advection, gas balance and heat conservation. The interplay of these various sub-processes is illustrated in the paper.Two case studies are presented which illustrate specific features of the model for different applications and how these have helped to identify key areas of concern. The first is focussed on chalcocite heap bioleaching, which shows that by nature of the reaction the process is strongly dependent on the initial supply of acid to the mineral site. In heaps this acid supply can be severely limited by the rate of diffusion from channels of flowing solution into stagnant zones of the heap, whereas in narrow-bore laboratory columns this effect is not observed."

Jan 1, 2003

By S. Fawell, H. R. Manouchehri

The main electrophysical properties, i.e., dielectric constant and electrical conductivity, of pure calcite, quartz and wollastonite mineral samples were measured and their triboelectric charge attributes were investigated by contacting minerals particles with different tribochargers made from different materials. In addition the energetic work function values for mineral samples were estimated due to their acquisition charge. Besides, the behaviour of triboelectrically charged of different particle size fractions of mineral samples were inferred. Finally an attempt were made to translate the findings from single mineral systems to a real carbonate ore. The results exposed good prospects to beneficate the examined minerals by triboelectric separation.

Jan 1, 2002

By Ali Ameli

Design loads are limited for piles relying upon toe stresses in rock due to uncertainty about the rock quality over the whole pile diameter because of rock mass properties or construction effects. The paper discusses the use of video images to evaluate rock quality at the bottom of piles socketed into graniodorite bedrock in a steel pipe pile project. Skillful interpretation was required to assess the 3D properties of the rock from video images. It is necessary to observe the rock mass characteristics near the project site for better perception of the rock features from the images. Video image interpretation skills were established by the evaluation of the cores drilled under the socket base and the results of pile loading tests. Correlations were found between rock appearance in the images and the rock socket drilling records. Rock socket acceptance criteria were developed through monitoring the drilling operations for the specific site procedures. Video images then served as one of the quality-assurance tools together with probing and pile loading test. Lessons and methods learned from video inspection in this project could be used to evaluate rock quality in similar cases.

Jan 1, 2006

By Philip Arthur

The ISASMELT process is making a significant contribution to the global metals industry. ISASMELT furnaces are now operating successfully in eight different countries and treating approximately 3 million tonnes of concentrates and secondary materials per year. The process is currently used in both lead and copper smelting. The most recently commissioned plants were in Germany and China, one for treating scrap copper and the other treating low-grade copper concentrates. The Copper ISASMEL T furnace ("CIF") at Mount Isa Mines Limited (UMIM") has continued to set new operational records, with throughput of more than I million tonnes of concentrate per year and very low operating costs. This paper summarises the latest operational data from the Mount Isa Copper ISASMEL T plant and outlines the successful approach to industrial R&D taken by MIM in the development of the ISASMEL T process.

Jan 1, 2003

By C. M. Rule

Stirred milling using either horizontal or vertical mills has made a rapid entrance into PGM ore and tailings concentrator flow sheets. Currently there are in excess of 40 units installed in either mainstream, ?MIG? or intermediate concentrate regrind, ?UFG?, applications in PGM, primary ore treatment plants or in tailings scavenging and reclamation treatment plants. This represents a total of approximately 70 MW of installed fine grinding equipment. This paper outlines the reasons why the technology take-up has been rapid and illustrates the advantages of this technology over conventional milling. Keywords PGM, platinum group metals, UG2, Merensky, platreef, stirred milling, MIG?mainstream inert grinding, UFG?ultra fine grindingof intermediate flotation concentrates, IsaMill?, Metso SMD?, Deswik, ceremic grinding media, QEMSEM, MLA.

Jan 1, 2011

By Mark P. Meyer

During 1991 through 1993, the U.S. Bureau of Mines (Bureau) -Alaska Field Operations Center (AFOC) in cooperation with the Bureau of Land Management (BLM) -Arctic District Office and the State of Alaska, Division of Geological and Geophysical Surveys (ADGGS), conducted exploration, geological, geochemical, geophysical, mineral resource, and mineral potential investigations in the 6.7 million hectare Colville Mining District (CMD) study area. This mining district study area, located in northern Alaska, includes the Colville River drainage basin as well as 0.35 million hectares of the southern part of the National Petroleum Reserve in Alaska (NPRA). This investigation was conducted as part of the Bureau's continuing Mineral Land Assessment (MLA) mining district program. The Bureau's MLA mining district program is designed to provide reliable and comprehensive mineral resource information that supports mineral resource policy and land use decisions made by Congress and Federal land management agencies.

Jan 1, 2011

By Christian Roche

Our study is focused on the sub-assembly con-tact shoes, pressure rings and pressure bellows. We were keen to mainly study [ ] 1.The contact shoe design 2.The most efficient pressure to ensure an optimal electrical contact between the contact pad itself and the casing 3. The contact shoe cooling circuit in view to provide to the shoe the best mechanical and electrical characteristics in order to bring to the users of COFOR® components a new standard in process setting technical solutions. A finite elements simulation, combined with a thermal and structural studies were used. Our presentation which follows is dedicated exclusively on the influence of the contact shoe cooling system on the process through a thermal and structural analysis. [ ]

Jan 1, 2007

By M. M. Fine

Research on the solid-fuel reduction of Knob Lake iron or was conducted to upgrade lean and high-grade ores and recover metallized products suitable for ironmaking or steelmaking. The program included bench-scale tests plus a number of continuous campaigns in a 34-inch by 36-foot rotary kiln. In the laboratory, metallizations in excess of 90 percent were achieved by reduction of crushed ore with lignite at 950° C. Subsequent grinding (to minus 200 mesh) and wet magnetic separation yielded concentrates analyzing less than 3.0 percent SiO2 and more than 90 percent Fe. Virtually complete recovery of the iron occurred. During early continuous tests the crushed ore created a serious ringing in the kiln which was solved by balling the fines with bentonite. Unfortunately, at this temperature (950° C) the bentonite militates against the concentratability of the metallized product. For example, a run on direct-shipping ore produced concentrates of 89.5 percent Fe and 4.5 percent SiO2. At 500° C the adverse effect of bentonite disappeared and concentrates of 88.4 Fe and only 2.5 percent SiO2 resulted. However, with comparable feed r Los, the metallization dropped to 73 percent.

Jan 1, 1969

The risk associated with mining induced seismicity is one of the major threats to the safety and sustainability of deep underground mines. This paper describes techniques that allow site practitioners to efficiently control such risks in mines. The proposed approaches rely on ground support to strategically control seismic risk and re-entry time to tactically control this risk. The strategic approach is based on the detailed understanding of past seismicity to as certain the seismic hazard of individual sources throughout the mine. This approach also relies on assessing the potential damage that these sources can induce on nearby excavations using the excavation vulnerability potential (EVP) and rockburst damage potential (RDP) concepts proposed by Heal et al. (2006). It is then possible to investigate how to reduce the risk of experiencing damaging seismicity in mine drives by locally enhancing the ground support system. The tactical approach relies on a proposed methodology to estimate reliable re-entry times or exclusion periods based on the seismic decay following blasting. Some examples of how these techniques have been applied in Australian mines are given.

Jan 1, 2009

By Jay C. Hanson

Various electrical and electromagnetic (EM) geophysical techniques are currently being evaluated by the U.S. Bureau of Mines for their effectiveness in the detection and monitoring of electrically conductive (1 to 5 S/m) lixiviant (leach solution) to depths of 600 m, either above or below the water table. These techniques include magnetotellurics (MT) , controlled source audiofrequency magnetotellurics (CSAMT), resistivity and focused resistivity, ground-penetrating radar (GPR), frequency-domain electromagnetics (FEM), and time-domain electromagnetics (TEM). Of these techniques, TEM may be the most effective, but CSAMT and focused resistivity also hold promise. Geophysical computer modeling of the borehole TEM technique was conducted based on an idealized geoelectric section (layered earth) with characteristics based on the Santa Cruz porphyry copper deposit near Cas a Grande, AZ. Layer resistivities and thicknesses were obtained from geophysical data and geologic logs available from the site. Modeling of borehole TEM in both preleach and during leach situations was conducted. Simulating the TEM method using computer modeling proved to be encouraging since there were substantial differences between leached and nonleached responses. The modeling does not prove the effectiveness of TEM in the field, but does indicate that detection of deep lixiviant zones is theoretically possible.

Jan 1, 1992

By L. Mukka

The existing main mine ventilation system for the production areas to the Kiruna mine was constructed during the period 1994-1996 and extended with 4 more shafts, including fan stations, for the sea ore body from 1997-1998. Two papers have been presented from this project at the 7th US Mine Ventilation Symposium in 1995 and at The 6th International Mine Ventilation Congress in 1997. In 2005, pre-studies for a new main haulage level were started. Different haulage methods were presented including ventilation systems. The pre-studies showed that the existing ventilation system, including fan stations for the new main haulage system in the production area, could be extended. However, a new system for the central area, which was not in the initial investment program, would be needed. In the beginning of 2006, a decision was made to design a new ventilation system for the central area to make it possible to get air to the development work for the new main haulage system, independent of the haulage method. This system was operational by the beginning of 2007. The new main haulage system, which was decided to be located on level 1365 m, only requires that the existing shafts be extended - the capacity of the fans seems to be enough. However, the problem is that the existing level 1045 m and the new level 1365 m have to be in operation in parallel for approximately 7-8 years. The challenge for the moment is determining how to ventilate the production areas for both levels at the same time, while simultaneously constructing the extended system. This paper will describe the problems associated with the extension of the main ventilation system and some potential solutions for these problems. The new main haulage level 1365 m must be in operation by 2012.

Jan 1, 2009