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By K. Fuenkajorn, J. J. K. Daeme

Ring tension tests have been conducted on 229 mm (9 in) diameter disks of Grande basaltic andesite and Pomona basalt with various center hole sizes in order to study the relationship between ring tensile strength and relative hole radius (hole radius/disk radius). The tensile strength, [ ] decreases as the relative hole radius, [ ] increases. A power equation, [ ] where C and R represent the coefficients of strength and shape, respectively, adequately represents the ring tensile strength as a function of relative hole radius over the range investigated. This equation can be used to distinguish the effect of the hole size from the strength results, to predict the tensile strength of a ring sample containing arbitrary hole sizes, and to approximate the critical relative hole radius of the material tested.

Jan 1, 1986

By J. J. Kollé

A compressed-water hydraulic pulse generator (HPG) for nonexplosive blasting of rock and con¬crete is described Energy is stored in the HPG by compressing water to ultrahigh pressure. A large, fastopening valve discharges the com¬pressed water, resulting in a high-energy impulse. The HPG can be used for small-scale bench blasting by discharging the water through a nozzle that is closely fitted into a borehole. A bench blasting system requires an HPG, a drill and an indexing mechanism to allow insertion of the HPG nozzle into a drilled borehole. Systems with discharge energies ranging from 40 to 250 kJ have been used to excavate hard rock, including andesite, granite and quartzite. The largest system can excavate 15 t/h (16.5 stph) of massive quartzite based on a 2-min cycle time for hole drilling. Blasting with an ultrahigh-pressure hydraulic pulse generator was demonstrated as an effective means of excavating hard massive rock under the confined conditions of a tunnel opening or underground sloping panel. Hydraulic blasting provides a continuous mechanized mining capability that is well suited for deep-level mining and urban excavation sites where explosives are prohibited

Jan 1, 1997

By Edward J. Hasenohr

Geochemical studies were under- taken in the Breckenridge mining district to test the effectiveness of soil and rock-chip samples in high- lighting known mineralization in the district, and in locating sites of possible porphyry-type mineralization, if such mineralization is present in the area. Soil sampling can be done more quickly and more cheaply, but it does not provide a direct site- specific sample of mineralized rock. In well-developed soils, supergene effects may mask and/or displace primary hypogene effects; and even in places where the soils are poorly- developed, as in the Breckenridge district, the masking effects may be felt. Soil anomalies, if present, likely will be of lower amplitude and more diffuse (widespread) than corresponding rock-chip anomalies. On the other hand, detailed rock-chip surveys are more time-consuming and expensive, even though they yield direct geologic information in addition to the chemical data. The goals of the combined soil and rock-chip programs were (1) to com- pare the data from the two; and (2) test the effectiveness in identifying significant chemical anomalies with respect to the geology of the district, as it is presently understood.

Jan 1, 1982

By L. A. Pursell

The case history, which is the subject of this paper, involves the expansion of a lime plant in Texas. The major new production unit is to be a 545.45 tonne per day coal fired rotary kiln. Auxiliary facilities include additional quarry haulage equipment, modifications to the crushing plant, a hydrator, storage facilities, and a loading system. The existing plant consists of a high calcium limestone quarry, two coal fired rotary and 10 gas fired shaft kilns, nth crushing, screening, stockpiling, hydrating, storing and loading facilities. The proposed modification would increase quarry volume from 545,000 tonnes per year to 805,000 tonnes per year. The plan also includes the addition of dolomitic lime to the product line which requires the purchase and handling of 186,000 tonnes of screened, washed dolomite yearly. A decision to undertake such an expansion was previously a simple and straight forward process. Such a decision now faces a major and complicating obstacle which can delay the project, raise the expected cost, or prevent it entirely.

Jan 1, 1980

By R. Schuerch, C. Cimiotti, M. Piemontese, N. Karlin, P. Perazzelli, P. Halton

The new Los Angeles, California JWPCP effluent outfall tunnel will transport secondary-treated effluent from the Joint Water Pollution Control Plant in Carson to White Point Manifold. The tunnel will be approximately 7 miles (11 km) long with a finished internal diameter of 18 ft (5.5 m). The TBM is designed to cope with high water pressure up to 10 bar. The geotechnical challenges are due to the heterogeneous subsurface conditions: in the first half of the alignment, the tunnel runs through soils with a low overburden under urban areas, and, in the second half, the tunnel runs through extremely weak, intensely faulted rock masses with high overburden. Following an overview of the project, this paper focuses on the northern portion of the alignment and presents a decision-making procedure developed during pre-excavation phase in order to cope with the expected heterogeneous conditions during mining. The risk assessment and the TBM operational design of the southern portion will be dealt with in a future paper.

Jun 13, 2023

By Todd S. Harris

Industrial minerals or non-metallic minerals are loosely used terms applied to a diverse assortment of materials which, in many cases, have nothing more in common other than the fact that they are neither metals nor fuel minerals. To help bring order to this otherwise random assortment of minerals, we have grouped these materials into two main categories; chemical and physical minerals, and nine sub-categories based on end-use applications as shown in Table 1. Chemical minerals are products which are principally used for the specific chemical elements they contain, whereas physical minerals are products which are used to meet specific performance specifications. The latter part of the 1970?s, in particular 1978, were considered peak years in terms of production and sales for many industries, By using 1978 as a base year, we can evaluate wherethese markets stand today after the recession of the early 1980's and the recovery which began several years ago. From this historical overview and appraisal of the current situation, various assumptions can be drawn as to which markets are expected to perform well into the 1990's.

Jan 1, 1987

By A. P. Massmann

Design for economical operation, minimum operating labor and minimum maintenance for labor and supplies are virtually inseparable. Each consideration has a vital bearing on the other. Let us assume that we have the design complete for the most economical operation with a minimum of operating personnel. This means, in addition, that we have the fewest number of operating units consistent with the product requirements for a team or metallurgical coal which we are called on to produce. The number of units will vary greatly, being influenced by design, washability characteristics, tonnage and degree of quality control necessary by reason of producing a product for metallurgical, steam or domestic use. The units involved most ordinarily for any type coal preparation plant will number as a minimum the following: 1. Hoppering R.O.M. Coal 2. Feeding

Jan 1, 1959

The Sandvik Group (Sandvik AB), headquartered in Sandviken, Sweden, continues to expand its worldwide operations growth. After recent acquisitions, including Tamrock, headquartered in Tampere, Finland, the company now has annual sales of more than US$5 billion (SEK 40 billion). With the acquisition of Tamrock, Sandvik has further increased its interests in the mining industry. Sandvik Rock Tools, a familiar name in the mining industry, is one of the world's leading suppliers of rock-drilling tools. And Tamrock is one of the world's leading suppliers of drilling machinery, loaders and equipment for rock-excavation operations. Sandvik believes that the two companies combined offer customers "maximum productivity through total system solutions, including machinery, service and tools." In 1997, Tamrock posted sales of US$940 million (SEK 7.5 billion). In addition to its expertise in drilling tools and equipment, Sandvik is supported by its collective resources in specialty steel and cemented carbide. These resources include extensive research and development capabilities, with annual investments in R&D now at about US$150 million. As a result of the R&D programs, internal expansion and acquisitions, the company has nearly doubled in size during the past four years. From 1994 to 1997, nearly US$1 billion was invested in internal growth and another US$825 million has gone towards acquisitions. Return on net assets is now 22% annually. In addition to Tamrock, acquisitions of interest to the mining community include Drillmaster Inc., Houston, TX. The acquisition of Drillmaster (by Sandvik Rock Tools) has further strengthened Sandvik's position in down-the-hole drilling tools. Other major recent acquisitions by Sandvik include Kanthal, a Swedish manu¬facturer of metal and ceramic-resistant materials for electric heating furnaces, household appliances and elec¬tronics, and Precision Twist Drill, Crystal Lake, IL, one of the leading producers of high-speed cutting tools. With more than 38,000 employees worldwide, the Sandvik Group is divided into six separate business areas. Each area is responsible for its own R&D, production and sales: ? Sandvik Mining and Construction. Including Tamrock and Sandvik Rock Tools, this business area boasts of offering the most comprehensive range of "rock-working" products. These include drilling rigs, loaders, rock-excavation equipment and rock drilling tools. ? Sandvik Specialty Steel. This area includes Sandvik Steel and Kanthal, manufacturers of stainless steel tube, strip wire and bar, as well as high-alloy steel and specialty metals. ? Sandvik Tooling. This business area consists of tools and tooling for metalworking applications. Sandvik Coromant is a market leader in the development, manufacture and marketing of tools using cemented carbide, ceramics and extremely hard materials, such as diamond and cubic nitrite. CTT Tools is the world's largest manufacturer of high-speed steel tools and is now expanding operations into solid cemented-carbide tools. ? Sandvik Hard Materials. This segment produces a full range of "hard materials," ranging from cemented carbide to diamond. This area manufactures and markets a full range of cemented carbide blanks for tool manufacturers, as well as components and rolls. ? Sandvik Saws and Tools. This business area manufactures high-quality handsaws and metal saw blades, as well as hand tools ranging from wrenches to chains for logging machines. ? Sandvik Process Systems. This segment manufactures steel belts, process systems and automatic sorting systems for the chemical

Jan 1, 1998

By J. M. W. Mackenzie

Three major developments have dominated the recovery of gold from ores, viz; 1846 Elsner's studies of gold solubility in aerated alkaline cyanide solutions 1887 MacArthur and Forrest's process based on zinc precipitation 1980+ Large scale development of the CIP process The brevity of this list for a metal whose extractive metallurgy has been as widely studied as any metal reflects the fact that the chemistry of the gold recovery process, as opposed to the engineering has seen few significant breakthroughs in over a century of application. to The purpose of this paper is introduce a new chemistry for gold recovery which may, in the future, add significantly to the technology of gold recovery. This new chemistry is based guanidine functionality - (R2R2N) 2 C = N R2 on the In developing the use of the guanidine functionality for the recovery of gold as the aurocyanide anion from leach solutions and pulps, Henkel has, as its objective, the development of an effective gold selective ion exchange resin. As will be seen, the initial investigation of the properties of the guanidine functionality in the solvent form for gold recovery lead to some significant metallurgical developments of their own but, the foremost objective was, and remains, the development of a resin for gold recovery. As a part of this development project, Henkel has entered into association with Mintek, South Africa, and this ongoing association has the potential to develop RIP/RIS technology for the gold industry. More details on Henkel's gold recovery technology and Mintek's role in this programme are given in (1). an The application of ion exchange resins to gold recovery is not new and many reviews have been published on the advantages of this process, and on the current state of the art of gold recovery by ion exchange resins. (2)(3)(4) Widespread application of ion exchange resin based processes for gold recovery has, however, not occurred to date. Fleming and Cromberge (5), described some significant pilot plant RIP trials in South Africa and the partial success of these pilot plant trials held out the tantalising possibility of a breakthrough in gold recovery based on RIP technology. Despite this pioneering work, only two really significant applications of RIP technology for gold recovery exist today. These are the Golden Jubilee Plant in the Eastern Transvaal South Africa and the widespread, although in some respects technically backward, use of ion exchange for gold recovery in the former USSR. There are two main reasons for the current scarcity of RIP and RIS plants used for gold recovery. These are: 1. 2. The perceived problems of engineering RIP plants The lack of a resin having suitable chemistry for both gold loading and gold elution The problems of engineering RIP plants have been largely overcome in the last 25 years. Much of the development in RIP plant design took place in the uranium industry during the rapid expansion of that industry in the mid 1970's. In addition, the development of CIP engineering systems has lead to the development of in-pulp solid extractant based metallurgical plant designs which can, with limited modification, be adopted to RIP. The lack of a resin having suitable chemical properties has almost certainly been the main reason for RIP/RIS not being introduced into the gold industry over the past decade. Attempts to use RIP/RIS have focussed on either conventional we ak base or conventional strong base resins. The weak. base resins have the disadvantage that they

Jan 1, 1993

By X. K. Jiang

Pneumatic, triboelectrostatic processing of physical mixtures containing fine (-200 mesh) particulate may have significant application potential in the mining and energy industries. Such dry processing methods, especially for finely comminuted materials, have not been examined in as much detail as wet processing methods nor have been part of the training or education of mining and process engineers. We have examined fundamental and applied physical and engineering factors controlling triboelectrostatic beneficiation of fine-sized physical mixtures, one of which -combustion fly ash -has size, heterogeneity and mineral concentrations typical of those expected in mined minerals. The applicability of dry processing, however, cannot be readily evaluated because of the unavailability of standard procedures for process assessment.

Jan 1, 1999

By W. K. Utt

This report discusses U.S. Bureau of Mines' research involving modem vehicle position determination techniques in surface mining. The applications would include haul trucks, power shovels, and drilling rigs. Accurate position determination of these vehicles in near real-time is expected to result in safer and more efficient mining operations. The requirements for a vehicle position monitoring and warning system were determined. After screening several concepts, the global positioning system (GPS) and a radar positioning system were selected for further evaluation. A state-of-the-art GPS receiver was taken to a surface mine to assess the feasibility of receiving the satellite signals. A state-of-the-art radar positioning system was evaluated with regard to accuracy.

Jan 1, 1995

By R. J. Lutton

The U. S. Army Corps of Engineers is seeking empirical slope data from mining companies and other organizations to help establish guides for engineering Judgment in crater excavation for canals and other civil works. Slopes from about 100 open pits and other excavations range in heights to greater than 1000 ft. Factors known or expected to affect stability (and optimum slope inclination) are: geological structural orientation, geological structural ordering, method and technique of blasting, design life of slope, groundwater conditions, depth of excavation, climate, and height. These and other more subtle factors appear to combine and produce an overall effect brought out best on a family of empirical curves relating slope height and inclination.

Jan 1, 1968

By G. T. Adel

This paper presents the highlights of a general-purpose simulator for mineral processing plants that is being developed at the University of California, Berkeley. The state-of-the-art structured design methodogy based on a top-down design approach is being used to construct a modular and completely structured simulator such that it is independent of the unit operation models and routines. The simulator provides for two levels of operation allowing prebuilt or user-built simulation flowsheets depending upon the degree of computer knowledge expected of the user. The philosophy used in designing this simulator appears to be unique in the field of flowsheet simulation. The paper also includes a mini-example demonstrating the usage of the simulator.

Jan 1, 1982

By Paul R. Thomas

This paper addresses the long-term cost and availability of primary gold production from the Republic of South Africa. Forty-four major producing or developing operations were evaluated. The analyses present estimates concerning 1) total refined gold potentially available from demonstrated resources, 2) annual production potential into the next century, 3) long-term weighted average total costs for underground mine production and surface waste reprocessing, 4) the expected annual decrease in gold production, and 5) the ability of other market economy countries to compensate for the anticipated decline in South African gold output. This paper draws upon the data and analyses of a recent Bureau of Mines, U.S. Department of the Interior, Minerals Availability Program appraisal that evaluated the worldwide availability of gold and silver from primary precious metal operations and as a byproduct of base metal production.

Jan 1, 1984

By J. K. Neathery, T. X. Li, H. Ban, J. L. Schaefer, J. M. Stencel, X. K. Jiang

Pneumatic, triboelectrostatic processing of physical mixtures containing fine (-200 mesh) particulate may have significant application potential in the mining and energy industries. Such dry processing methods, especially for finely comminuted materials, have not been examined in as much detail as wet processing methods nor have been part of the training or education of mining and process engineers. We have examined fundamental and applied physical and engineering factors controlling triboelectrostatic beneficiation of fine-sized physical mixtures, one of which - combustion fly ash - has size, heterogeneity and mineral concentrations typical of those expected in mined minerals. The applicability of dry processing, however, cannot be readily evaluated because of the unavailability of standard procedures for process assessment.

Jan 1, 1999

By V. Carabias-Hütter, A. J. Basu

The paper aims at promoting sustainability assessment and reporting into practice using a globally acceptable set of guidelines and a common framework for internal and external reporting at a project/site level. Indicators are used for measuring performance, and this paper addresses development and implementation of performance indicators for sustainability assessment and reporting at local as well as global levels. The selection of a proper set of indicators is a challenging task. The indicators selected should provide the expected information for making right decisions. Relevant and credible sustainability reporting supported by a consistent performance indicator system can be the starting point for benchmarking environmental and social performance for the natural resources sector.

Jan 1, 2004

By Li Honggui, Liu Maosheng, Zhao Zhongwei, Sun Peimci, Li Yunjiao

Leaching of Shizhuyuan low-grade refractory tungsten ore was carried out in a mechanically activating reactor. The effect of experimental parameters-temperature, amount of Na2C03, addition of NaOH, ratio of liquid to solid and leaching time - on the recovery of WO3 was studied. The WO3 recovery up to 96.99% have been achieved when the tungsten ore was digested by soda not more than three times the stoichiometric amount at 185-195°C for 1 .O-2.0 hours. Iso-extraction countour diagrams were drawn to illustrate the effect of various parameters on leaching. The WO3 recovery could be expected to increase 10-15% compared to that of conventional soda autoclave process.

Jan 1, 1995

By P. F. R. Altounyan, I. W. Farmer

Groundwater freezing was used to stabilise 8m thick beds of saturated and weakly cemented sands at a depth of 170m, during driving of twin 1 in 4,5.2m o.d. circular drifts from the surface to the Coal Measures through 600m of Permo-Triassic strata. Instrumentation was installed during erection of the lining in frozen and unfrozen ground to measure ground and groundwater pressures on the lining and ground temperatures up to lm into the frozen ground. Observations showed that following thawing, effective lining stresses in the frozen zone were low, indicating minimum strata disturbance during freezing and subsequent machine excavation. Groundwater pressures were lower than expected.

Jan 1, 1981

By B. Kolonja

This paper considers simulation of truck dispatching system designs using maximum expected production of the truck-shovel system as the measure of performance. Two methods are utilized, multiple comparisons with the best (MCB) and the combination of MCB and the variance reduction technique known as common random numbers (CRN). These two techniques are compared via simulation experiments. The results show that the combined procedure of MCB with CRN is the superior tool to reduce the total number of replications needed to ensure the specified probability of correct selection over the finite number of designing systems. In this case study, MCB with CRN reduces the variance by 29% and the number of required replications by 48%. Also, the MCB with CRN procedure narrowed the confidence interval by 18%.

Jan 1, 1994

By Ulises Deveze T.

The coal company Minerales Monclova, S.A. (MIMOSA), the owner of the Mimosa R Line, is a subsidiary company of Altos Hornos de Mexico, S.A., the largest steel plant in Mexico with an annual capacity of 2.5 million metric tons of steel ingots. The raw material's which are used in the steel plant are provided by the following companies: La Perla Minas de Fierro, S.A., iron ore; Cia. Minera de Guadalupe, S.A., Cia. Carbonera La Sauceda, S.A. Cia. Minera La Florida, S.A., and Minerales Monclova, S.A., which provide the coal used for coke, and altogether constitute the industrial group AHMSA. The coal property of Minerales Monclova, S.A. is located in the Sabinas coal area in the northwestern part of the Sabinas basin.

Jan 1, 1974