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By James M. Franklin

Research on modern hydrothermal systems provides quantitative measures of the processes of formation of hydrothermal fluids and of precipitation mechanisms from them. Studies of ancient deposits provide new information regarding volcanological processes that are related to the deposits, as well as data on their spatial and temporal compositional variations. Mew exploration guidelines result from both aspects of research. The most fundamental requirement for large metalliferous hydrothermal systems is an abundant heat supply for the upper two kilometers of the crust. This heat may come from a focused heal source (shallow-level subvolcanic intrusion), but ambient heat also may have provided enough energy for the reactions necessary to effect leaching of metals, especially where heat flow is particularly high (i.e. very large or high-temperature magmatic source, such as ultramafic environments). For most VMS systems, the majority of the metals were derived through leaching from footwall strata; in addition interstratal fluids may enter subvolcanic intrusions during episodes of magma a chamber "cracking," engendering some '?magmatic" component in the hydrothermal system. Direct contributions of metalliferous magmatic fluid also may be significant from arc-related or back-arc felsic or alkalis systems. These latter contributions may form exceptionally high - grade portions in some deposits. Subvolcanic intrusions, which are excellent indicators of high heat flow and may have been the direct driving mechanisms for some stems undergo two stages of alteration: On intrusion emplacernent. fluids may rapidly enter and react with their mesostatic portions, evident in the sills in the Middle Valley. High temperature interactions caused albitization and destruction of oxides and sulfides, releasing metals. During terminal hydrothermal stages, the metalliferous fluid collapsed into the intrusions, forming disseminated and vein sulfides.

Jan 1, 1998

This Department handles all ores prior to blast-furnacing, the object of the operations being to mix the lead-bearing material with fiuxes, eliminate sulphur from the mixture, and produce a homogeneous sintered product which is chemically and physically suitable for treatment in the blast furnaces.During the financial year ended the 30th June, 1937, the tonnage of charge treated was 458,960 tons, containing some 183,470 tons of lead and 8,504,000 oz. of silver.The quantities of the principal components of the charge treated were as follow:-

Jan 1, 1937

By Khamis Y. Haramy

This paper summarizes ground control studies of longwall panel entry systems in two Western U.S. coal mines. Presented are comparisons of in situ pressure change measurements and assessments of chain pillar and entry behavior under a wide range of cover. Results indicate that no one entry system design is universally applicable, and that site-specific factors need to be considered for panel entry design. Relationships between overburden depth, face advance, and magnitude and location of the forward abutment are discussed for western operations. In addition, analysis indicates that use of yield pillars may reduce or eliminate some stress-related problems that plague longwall panel entry design.

Jan 1, 1989

By Zhao-cheng Liu

Iron oxide red pigment powders of high quality were synthesized from pyrite cinders. Iron ox-ide red pigment powders were synthesized by hydrothermal method from the precursor of Fe(OH)3 and Fe(OH)2 colloid, which were obtained after ammonia solution reacted with acidic leaching solution produced by the reaction of pyrite cinders with sulfuric acid. Effects of reaction concentration, reaction temperature, reaction time, pH value and n(Fe2+)/n(Fe3+) on main properties of oxide iron red were studied by experiments. The prepared particles were characterized by means of X-ray diffraction (XRD) and scanning electron microscope(SEM). The results revealed that the synthesized iron oxide red particles were _-Fe2O3 and pseudocubic with particle size of 0.50~0.75µm. Furthermore, the quality of iron oxide red pigment powders reached the first grade of national standard (GB1863-89 ).

Jan 1, 2009

By M. England

Keywords: Bi-directional tests, Osterberg cell, O-cell®, static load tests, Timeset® Static load testing, where loads are applied vertically to the top of the pile and often referred to as 'top down testing', has been used for many years and has become a 'standard' test for the world of foundation engineering. The method, although well developed, cannot be used under certain circumstances, magnitude of load being a particular issue. There is a finite limit to the load capacity that can be applied with either kentledge, the use of reaction piles or anchors, and as the loads increase, the costs escalate dramatically. A novel test method seeks to overcome all the associated problems of large scale and restrictive area "top down testing", utilising static load testing techniques. The method requires the foundation element to be divided into two or more sections and these can be loaded axially as required using a portion of the foundation element as a reaction. This paper presents some recent applications and developments in the use and application of the bi-directional testing technique using the Osterberg Cell or O-cell® and outlines some of the many advantages of the system. Recent bi-directional test loads applied to bored piles have mobilised capacities of 279 MN and with flight auger piles up to 25 MN.

Jan 1, 2006

By 12670

The Cigar Lake project will develop the world’s second largest high-grade uranium deposit. The Cigar Lake Phase 1 orebody contains approximately 226 million pounds U3O8 at an average grade of 20.7% U3O8. The mine, to be operated by Cameco Corporation, will use a unique water jet boring mining method to cut previously frozen ore. A distinctive ore handling design is required to handle the highgrade ore slurry exiting the mining machines. The ore will be crushed and ground underground, with the ore slurry then pumped to surface. Loaded into purpose-designed containers on tractor-trailer units, the ore slurry will be trucked to Cogema Resources Incorporated’s McClean Lake mill. McClean Lake will leach all of the ore. Forty-three percent of the resulting uranium solution will remain at McClean Lake for processing into yellowcake. The other 57% of the uranium solution will be shipped to Cameco’s Rabbit Lake mill for processing into yellowcake there. Detailed design for the Cigar Lake project is now underway. Barring regulatory or market delays, production could start up as soon as early 2006.

Jan 1, 2004

By F. M. C. C. Vieira

The DEEPMINE Research Programme sought to develop the technology and competence to mine gold safely and profitably at depths of 3 to 5 km. Among the many issues addressed was the stability and support of rockpasses at ultra-depth. It was found that high virgin and mining-induced stresses could cause the walls of rockpasses to spall, leading to the deterioration and failure. A comprehensive programme of numerical modelling was conducted to investigate alternative mining layouts and sequences to ameliorate the problem.

Jan 1, 2005

By Valentín Choquenaira Bombilla

El presente trabajo describe el proceso de automatización de la planta concentradora BHPBilliton deTintaya desde el punto de vista del usuario final y así proporcionar una visión global sobre los aspectos relacionados con la automatización de nuestro proceso a través de sistemas de control distribuido (Distributed Control Systems, DCS) e inteligencia artificial (Sistema Experto).También se describe la arquitectura del control, las formas de conexión (Hardware) y la función que desempeña dentro del sistema cada uno de los componentes del sistema de control distribuido instalados en la planta concentradora de sulfuros de BHPBilliton Tintaya S.A. así como algunos conocimientos básicos de manejo del sistema composer y conductor NT (Software) para realizar las funciones de configuración, monitoreo y control del proceso desde unidades remotas y estaciones de trabajo.

Sep 12, 2005

Microfluidic Solvent Extraction for Mineral Processing of Copper Leach Solutions

Sep 13, 2010

By Thomas O. Glover

The mining industry of Cameroon continued to be dominated by crude petroleum. Crude petroleum production has become the most important facet of Cameroon's economic development. Oil production was estimated to be 6.3 million tons in 1983 compared with 5.2 million tons in 1982 and 4.3 million tons in 1981. Over two-thirds of its export income was attributed to crude oil. The country's only refinery, dedicated in 1981, has a production capacity of 2 million tons. Cameroon has become self- sufficient in petroleum products since commissioning the refinery. The oil sector contributed approximately 13.5% to Cameroon's gross domestic product in 1982-83. Oil production was expected to rise from 125,000 barrels per day in 1983 to 156,000 barrels per day in 1985 when output peaks. Cameroon's ultimate recoverable reserves have been calculated at 100 million tons, or 750 million barrels of oil.

Jan 1, 1985

Study on Reasonable Mineral Processing Flow Sheet of Yunfu Low-Grade Pyrite Ores Low-grade ores in Yunfu Pyrite Mining Area were investigated, in order to find an economical, reasonable and environment-friendly mineral processing technology, which is of low consumption and high efficiency in pyrite recovering, which can ensure that the quality of pyrite concentrate product is eligible for sale and the sulfur content of the discharged tailings meets the national emission standards. A flow sheet with a classification, a jigging for coarse-grain minerals and a spiral chute separation for fine-grained minerals was adopted, and the sulfur grade and recovery of the pyrite concentrate is 35.50 per cent and 86.70 per cent respectively, while the grade of tailings is only 6.70 per cent.

Sep 13, 2010

By David C. Girard, Larry Williamson, Leonard R. Benson, Ronald E. Bizzarri

On the east side of Washington DC, the DC Water & Sewer Authority is developing a Facility Plan for the Anacostia River CSO Control Projects, including 8 to 12 miles of CSO storage/conveyance and flood relief tunnels and associated facilities. The project includes major technical and non-technical challenges, including: completion under a Federal Consent Decree schedule; large diameter (estimated 25 to 35 ft) soft ground tunnels and shafts up to 200 ft depth; operations without use of active flow control systems; and close coordination with several major public and private construction and development projects that are being advanced in the project area.

Jan 1, 2007

By L. W. Hamel

"DUST CONTROL - GRANISLE COPPER LIMITEDINTRODUCTIONGranisle. Copper Limited is located in the north-central region of the Province of British Columbia, approximately 200 road miles north-west of Prince George. Mill startup was in November, 1966, at a rate of 5,000 tons per day, expanded to 13,000 in 1973. The primary crushing rate is 1,200 tons per operating hour, and the secondary 750, and they can be operated jointly or separately.DUST COLLECTION SYSTEMS There are seven dust collection systems ventilating the crushing and grinding complex. The individual pickup points are depicted on Figure 1 -""Crushing Plant Flowsheet"", and Figure 2 - ""Concentrator Flowsheet"", e.g. 1A, 1B, 3C, etc.System No. 1 - Primary Crusher The feed rock box of the Allis-Chalmers superior 42-65 primary crusher is ventilated by 19,000 CFM of air exhausted directly to atmosphere by a Sturtevant 426 M fixed discharge fan.No. Dust Pick Up Point CFM lA Crusher Feed Rock Box 19,000System No. 2 - Primary Crushing and Screening System No. 2 ventilates the primary crushing and screening equipment. A total of 19,000 CFM of air is exhausted by a Sturtevant 426 M fixed discharge fan through a Howden Type S - size 75 cyclone locally modified for wet scrubbing."

Jan 1, 1976

Reduce accidents associated with handling of the electrical trailing cable and the water hose on mining equipment. Approach Two reels were mounted on a loading machine to store and release the lines as required during face operations. How It Works A hydraulic motor, which is actuated by a treadle valve in the operator's cab, controls the reel on which 50 feet of electrical power cable is stored. A spring motor resists unwinding of the other reel on which 50 feet of water hose is stored. Both reels are mounted on the right rear of the loading machine. See Figure 1. Following common mining practice, the cable and hose are anchored to fixed points at the first intersection outby the face. Tramming forward causes the cable and hose to be pulled from the reels. Depressing the treadle valve causes the electric cable reel to turn and wind-in any slack in the cable. The spring tension on the water hose reel automatically rewinds the water hose when the loader is trammed in reverse.

Jan 1, 1978

By D Veneziano, J Van Dyck, R Snow, W Pytel, O Zanoli

Best practice standards generally recommend assessment of the environmental and societal risks posed by tailings storage facilities, but they rarely specify how the analysis should be made. As a case study, this paper describes a safety assessment of the Zelazny Most tailings pond operated by the Hydrotechnical Unit of KGHM Polska Miedz SA in Poland. The complete assessment includes a failure mode effect criticality analysis (FMECA) that considers all conceivable failure modes, but this paper focuses on one key mode, the loss of stability during the planned raising of the crest above its current level. Reliability against static dam failure considers uncertainty on the safety factor in a limit equilibrium approach. The threat of dynamic (earthquake induced) instability is assessed by developing a model of future seismicity as a function of the mining plan and considering uncertainty on the induced permanent displacements along critical sliding surfaces. We quantify the additional level of protection against outflow provided by the beach using an event tree with expert-assigned probabilities. Continuous monitoring of the dam for premonitory signs of instability and a set of loss-prevention plans in the case of a spill provide additional layers of protection; their effectiveness is quantified by estimating the fraction of the population that could be evacuated as a function of warning time. The probabilistic analysis indicates that the safety targets are met and produces practical recommendations on how to maintain and improve the safety level while the dam crest is raised above its current level.CITATION:Van Dyck, J, Pytel, W, Veneziano, D, Snow, R and Zanoli, O, 2015. Safety of a tailings storage facility against dam instability, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 253–262 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

By K. C. Ko, D. A. Pifer

The theory of probability with respect to the failure of structures is discussed. It is shown that the probability of safety, probability of failure, and factor of safety are directly related to each other and that as standard deviation approaches zero, the probability curves approach a unit step function which can be interpreted as the conventional factor of safety. The factor of safety is numerically the ratio of the load to the strength of the material at a particular point or plane in an engineering structure. Mathematically, it can be illustrated as a unit step function undefined at the point where the factor of safety is one (Fig. 1). The uncertainty of variation of soil and rock strengths require factors of safety much higher than those used in other engineering structures. The factors of safety used are generally determined from past experiences with similar structures. However, the factors thus determined do not have any theoretical meaning or do not indicate any relationship to actual safety.' It seems, therefore, logical to develop a system with a sound theoretical basis to obtain a more suitable factor of safety for structures. An application of elementary theory of probability indicates that it is possible to relate this number to theoretical and practical engineering facts.

Jan 1, 1971

By V A. Tsukerman

Prospects a new energy saving method for an efficient destruction of the sturdy and hard materials (rocks, ores, frozen soils, concrete blocks, etc) û the Electric Pulse Discharge (EPD) method of materials destruction for green processing in mining and processing of mineral raw materials are considered.The EPD-technologies give additional possibilities for solving ecological problems at the expense of increase of integrated approach of utilisation of minerals and industrial wastes. The scientific and technical level of executed development of EPD method is sufficient for organisation of design work to develop substantially new equipment. A number of plants have been developed and tested, including plants for processing raw material with minerals of jewels, plants for selection of mica from rocks, and plants for processing the merging of artificial mica.

Jan 1, 2002

As part of its research and development activities concerning coal mine operational/emergency communications sys terns, the Bureau of Mines commissioned several contractors to conduct electromagnetic (EM) noise studies and measurements that would aid the development of improved coal mine operational/emergency communications systems. The bulk of the noise studies and measurements were conducted in 1971. The Pittsburgh Mining and Safety Research Center (PMSRC) inherited the responsibility for monitoring the electromagnetic noise activities by mid-to-late 1971, and initiated a review and evaluation of the current and planned electromagnetic noise work. Arthur D. Little, Inc., (ADL) was asked by PMSRC to assist it in performing this review and evaluation by placing stronger emphasis on certain tasks of existing Contract No. H0122026. This technical memorandum report presents the findings, conclusions, and recommendations of our review and evaluation of the electromagnetic noise measurements of the five contractors we were asked to examine. Our review and evaluation effort included meetings and telephone discussions with technical staff of each contractor; serving as Technical Discussion Leader of a "Contractor's Round Table Meeting on EM Noise, Surface and Subsurface, Operating and Non-Operating Mines" called by the Bureau of Mines; examination and discussion of contractor reports and relevant open literature; sample verification calculations; and the documentation of our findings, conclusions, and recommendations by this report.

Jan 1, 1972

By John G. Kelly

"In 1982 an extensive study was carried out to determine the best means of size reduction for the ore to be hoisted through the borehole hoisting system at Sherritt Gordon's Fox Mine.The study examined three alternatives:1. a jaw crusher,2. pneumatic rockbreaker(s) at a grizzly, and3. hydraulic rockbreaker(s) at a grizzly.The final decision was a compromise between alternatives 2 and 3. Two rockbreakers, one pneumatic and one hydraulic, were installed over a single grizzly. Some modifications have been made to the system, but over-all it has operated at acceptable levels since its installation in July 1983.As all the ore passes through a jaw crusher before being hoisted to surface, an evaluation of the relative performance and cost-effectiveness of the jaw crusher and the two types of rockbreakers is possible. This paper outlines the initial study, and compares the three breaking systems in operation at Fox Mine.IntroductionThe Fox Mine of Sherritt Gordon Mines Ltd. is located 800 kilometres north of Winnipeg near Lynn Lake in Northern Manitoba. Production at the copper-zinc orebody began in 1970 at a rate of 3,000 tons per day. Over 12.5 million tons will have been hoisted from the underground mine when the ore reserves are depleted in October 1985.The mining method at Fox Mine is sub-level open stoping with delayed backfilling are from the upper level stopes, above the 2000 level, is mucked on the main levels established at 400-ft elevation intervals, and is fed through a central orepass to the crusher located on 2100 level. Production in the lower levels commenced in 1975, and ore from the 2200 and 2400 level stopes was hauled up a 15010 ramp by 26-ton trucks to the 2000 level orepass dump. Projected production rates from the 2600 and 2800 levels using the trucking system were too low, and therefore, in 1983 a borehole hoisting system was commissioned to hoist that ore'!'. One thousand tons per day of ore are skipped through an 8-ft diameter borehole from the 2650 level loading pocket and dumped on the 2000 level. The ore is transferred by LHD to the main orepass for crushing before being conveyed to the main shaft for hoisting to surface (Fig. 1)."

Jan 1, 1986

By G J. Corbett, T M. Leach

Although hosted within an Ordovician magmatic arc, the Peak Hill high sulphidation system displays features typical of youngerPacific Rim high sulphidation epithermal gold deposits. Regional NW trending transfer structures are inferred to localise the magmatic source at their intersection of the NS trending arc. Fluids have migrated from the magmatic source along NW structures and thence exploited permeable horizons, which have become silicified. Alteration displays typical zonation from silicification through assemblages characterised by alunite, pyrophyllite and kaolinite and is followed by breccia/fracture controlled sulphide and gold deposition. Sinistral rotation on the NS arc has dilated NW trending fractures to produce the WNW to EW dilational fractures which host the higher grade ore. Mineral assemblages are typical of formation distal to the magmatic source in an epithermal environment. The combination of alteration and mineralisation zonation with structure provide fluid vectors which target a magmatic source to the SE of Peak Hill.

Jan 1, 1995