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By J. W. Stewart

THE aim of this paper is to point out the various ways in which design is taught in standard four-year mining engineering curricula in American colleges and universities; to discuss the reasons apparently justifying the great diversity of procedure that exists along this line; and to indicate possible solutions to the difficulties now attending the teaching of design. A study was made of typical four-year mining engineering curricula in 15 colleges and universities of the United States (Table I). Great diversity in content of the various design courses, if taught as described, became apparent immediately. It appeared that it might be both interesting and instructive if the cause for this colorful variety could be found. Was the cause local mining conditions, departmental individuality, or actual necessity? Study of the school catalogues revealed that the various design courses could be classified into two fairly distinct types; namely, (I) those dealing with mine equipment or structures, and (2) those dealing with underground layout of mine workings. It seemed reasonable to label the first type of course "mining design" and the second type "mine design." Some such distinction must have been in the minds of mining educators, for we find both names (i.e., mine design and mining design) used to designate the design courses included in the various mining curricula. Unhappily, the name and the apparent content of such courses do not, in all instances, conform to the classification made here, although in most instances such conformation does obtain (Table I), It is possible that in the exceptional case the method of teaching a design course, and consequently the content of it, may have been changed at some time without change in the name of the course. Apparently only 3 of the I5 schools made an effort to cover both types of design in their curricula (Table I). Two other schools did not list or describe any course of study that could with certainty be taken as a design course. Of the remaining 10 schools, 9 gave a mining-design type of course and one gave a strictly mine-design type. Obviously, the preponderance of design courses afforded are of the mining-design type. Why? To answer this question, it is necessary to make a study of the prerequisites for the two types of design courses taught. In all schools the design courses were taught in the senior year; in eight, design was taught throughout both semesters; in two, it was taught during the first semester only; and in three it was taught during the second semester only. Consequently, excepting the last three cases noted, it is obvious that all prerequisites for a design course should be completed by the end of the junior year. PREREQUISITES What are the probable prerequisites for the different kinds of design courses as they appear to be taught? Let us take first the case of the mine-design type of course, having to do with layout of underground workings. Here it would seem that logical

Jan 1, 1941

By J. H. Morrish

"The delivered price of any mineral is the determining factor in converting untapped resources into economic resources. Transporting the minerals from the mine to the market plays a significant part in the total package. The expansion of the Western minerals industry in the last ten years has been paralleled by improved transportation systems to reduce cost, increase accessibility of resources and get the minerals to market in the shortest time possible. A review is made of developments, such as unit trains, complex multi-modal systems and containerized transport, over the last ten years, with specific movement outlined. The total transportation package of land transport, port and terminal facilities, and water transport, where needed, is stressed. As the volume of minerals movement expands, increasingly sophisticated and integrated transportation systems will have to be utilized. The development of solids pipelines and other possibilities is outlined."

Jan 1, 1973

By V. M. Johnston

The most abundant fuel resource in the U.S.A. is also the most under-utilized. Proven reserves of bituminous coal, sub-bituminous and lignite constitute from 60% to 90% of our total fossil fuel reserves -- dependent upon the parameters used by the analyst making the estimate. Despite this ample supply, bituminous coal provided only 20% of U. S. energy consumption in 1967 and 1968, this dropping to 17.57 in 1971 and 1972. By 1978, according to my projections, 16.7% of the Nation's mechanical energy will come from bituminous coal. However, our energy needs are growing at such a rate that the 20.6% provided by bituminous in 1967 equalled 480 million tons while the 16.7% of U. S. consumption visualized for 1978 will require nearly 650 million tons. In order to view coal's position with perspective in this developing energy crunch, it is necessary to examine the total energy situation. To this end, I have prepared a couple of tables which you should have before you. I chose this procedure rather than slides because I would need to utilize an entire wall to make the data visible to an audience. Therefore, I refer you to the long sheet entitled "U. S. Energy Consumption - Trillion Btu - 1967-1978." As you can see from the heading, I am confining my treatment of the problem to the intermediate term. In the long run, if we are willing to pay the cost, we can do a lot of things, including the complete conversion of coal into a sulfur-free fuel.

Jan 1, 1973

By D. Cruden

DISCODAT is a system of computer programs written for CANMET, Canadian Department of Energy, Mines and resources, to be used in analyzing geological data for rock slope design. The programs were written in Fortran IV for an IBM 360/67 computer. A program conditions field data from field forms for storage in a line file. Data may be selectively retrieved from the line file by a general retrieval program which uses a variety of relational operators. The retrieved data may be displayed as structural diagrams or histograms produced on a line printer or in a number of maps produced on a drum plotter. There is a logical sequence which leads to the characterization of those elements of the subfabrics of a rock mass which may be kinematically active. Structural domains within the rock mass can also be outlined by a procedure described as areal analysis. Costs for a complete analysis are usually substantially less than $l/discontinuity.

Jan 1, 1978

By Gary P. Sames

This report discusses some practical applications of a geotechnical investigation conducted by the U.S. Bureau of Mines that can help mine operators meet revised Federal regulations in their roof control plans. The investigation, designed to characterize roof conditions near the coalbed outcrop in drift coal mines in eastern Kentucky, revealed that weathered stress-relief joints near outcrop are crucial ground control factors in the region. The joints' origin and character were determined through underground mapping of many joints in coal mine roof and detailed observations and measurement of joint trends and physical characteristics in widely separated strip mine highwalls and roadcuts. This resulted in an understanding of stress-relief-joint patterns and the effect of various rock types on the intensity of weathering in the joints. That information is used in this report to show how stress-relief joints contribute to roof failure and how, through improved roof support and mine planning, safer roof support plans can be developed.

Jan 1, 1992

By Dean Brox

Tunnel boring machines (TBMs) have been used for the construction of various tunnels for mining projects for the purpose of access, conveyance of ore and waste, drainage, exploration, water supply and water diversion. Several mining projects have seen the successful and economic beneficial use of TBMs, and there is an increasing awareness of the benefits of TBMs for mining projects. Key technical considerations for the use of TBMs for the construction of tunnels for mining projects include geological issues (rock type, rock alteration, rock strength, rock abrasivity, durability, ground water inflows), depth of cover and the potential for overstressing/rockbursts, site access and terrain, portal locations, TBM constraints, minimum tunnel size, tunnel support requirements, contractor and labor experience, and project schedule demands. TBMs offer key project schedule benefits with high rates of progress, which is a unique economic advantage recognized for mining projects where timing is of the essence in order to advance mining development and achieve early startup for operations. A thorough evaluation of the anticipated ground conditions should be performed as part of the decision to adopt a TBM for a mining project. Minimum specifications for TBMs are necessary in order to prevent the incorrect type of TBM from being used. Appropriate geotechnical investigations are necessary in order to provide key information on the anticipated subsurface conditions for careful planning and design of the proposed tunnel alignment. The overall site and geological conditions associated with some projects may suggest that it is not appropriate to use TBMs for some mining projects due to a perceived higher risk.

Jan 1, 2013

By Bowen Li, Matthew D. Andriese, Jiann-Yang Hwang, Zhiwei Peng

"Magnetic iron sulfide ore particles heat rapidly by microwave (MW) irradiation generating plasma during oxidation of surfaces. The high temperatures produced by the exothermic event decompose local portions of samples forming a differentiated flux of partially melted silicate (si-mt) with entrained metal-sulfide (sul-mt) droplets. The si-mt forms crystals of olivine (01) in Ca-rich pyroxene (Cpx) melt that resorbs a portion of iron sulfide (Po). The immiscible sul-mt droplets of (Fe,Ni,Cu)1-xS contain magnetic subsolidus Ni-pyrrhotite (Ni-Po) with Cr-bearing ferrospinel (Mag). Sub-micron sized flecks of Au are found on the surface of a sul-mt droplet with scanning electron microscope (SEM).IntroductionSulfide ore deposits supply the world's mineral resource in the production of non-ferrous metals. Particularly, Cu-Ni deposits are chemically enriched in metals from high sulfur saturation during magmatic formation that creates the proper geochemical environment for metals enrichment [1, 2]. The sulfur and oxygen fugacity control redox conditions of a differentiated silicate/sulfur magmatic melt with the concentration of iron playing a dominate role in the chemical partitioning of metals in sulfide liquid [3, 4]. The initial magnetic crystallization of (Fe,Ni)i-xS monosulfide solution (mss) from metal-sulfide liquid has an exclusive effect on the fractionation of mineral assemblages (zoning) [5].Phase equilibria of sulfide melt (sul-mt) components are related by a miscibility gap with mss forming Ni-rich pyrrhotite (Ni-Po) followed by the crystallization of (Fe,Cu)1-xS intermediate sulfide solution (iss) [6]. Precious metals form stable chacogenides and are retained in solution until the final liquid solidifies. The redistribution of metals now occurs by subsolidus cooling of mss and iss that exsolve low-temperature Fe-Cu-Ni bearing mineral assemblages [7]. The proper interpretation of ore genesis increases processing capabilities by isolating chemically enriched zones during extraction and should be used to aid in sustainable mine site development [8-11]."

Jan 1, 2013

By C. Horstmann, D. Andreo, G. Barthold

"The concept of large single line grinding circuits provides a valid answer in project feasibility studies by reducing capital investment requirements compared to parallel lines for the same plant throughput rates. The benefits of this concept are reflected as well on the operational aspects, in terms of higher and greater process stability, and reduced operational costs mainly due to the associated lower maintenance expenditures. However, concerns exist in the minerals industry on whether large single line grinding could reduce the overall concentrator plant availability. The mechanical design and integrity, the mill and gearless mill drive integration, as well as assets management aspects of this type of equipment are the key to guarantee successful availability records. Together with an overview of the added value provided by large single line grinding circuits, this paper focuses on risk mitigation strategies during mill and gearless mill drive integration, as well as on the design of the equipment itself, for the key aspects which could put at risk the operations availability.INTRODUCTIONDespite a large long term demand for commodities, the mining industry has never faced complex challenges as it is doing today. Decreasing high-quality and accessible deposits, declining ore grades in existing mines, shortages of electrical energy (e.g. in Chile) and an aging workforce are the most significant among the megatrends affecting our industry. In addition to this, flat underlying commodity prices and high price volatility are currently posing strong requirements to miners when entering into the process of approving investments.Nowadays to get projects financially approved (optimizations, expansions, new plants), capital expenditure has to be reduced, as observed up to 30% compared to the last decade, and at the same time the plant design has to be such to demonstrate that operating costs will also be significantly lower than in the past.When it comes to the concentrator plant, the concept of large single line grinding circuits provides a valid answer in project feasibility studies by significantly reducing the capital investment requirements compared to parallel lines for the same plant throughput rates. The benefits of this concept are reflected as well on the operational costs, in terms of higher and greater process stability and reduced maintenance expenditures."

Jan 1, 2016

By W. W. Adams

Lower accident rates were the outstanding feature. of the second annual sand and gravel safety competition conducted in 1930 by the United States Bureau of Mines in cooperation with the National Sand and Gravel Association. Both the frequency and, severity rates for accidents were greatly reduced as compared with those shown by the first year's contest, that for 1929. Three times as many plants were enrolled, and the number of man-hours of work represented wad more than doubled. Seventy-six sand-and-gravel plants, situated in 20 States, participated in the competition, as compared with 26 plants, located in 13 States, in the year before. The number of man-hours of employment, which indicated the amount of exposure to occupational hazards, was 4,915,592 an increase of more than 100 per cent over, the previous year's total of 2.259,572 hours. The frequents of accidents declined from 74.4 per million hours for all plants enrolled in the first year's contest to 42.7 per million man-hours for all plants enrolled in 1930. The accident-severity rate was reduced from 9.7 days of disability per thousand man-hours of exposure in 1929 to 5.9 days of disability per thousand man-hours of exposure in 1930.

Jan 1, 1931

By R. R. Song, Q. Li, H. Xing, X. C. Wei

Geomechanical modelling of fault stability is an important part of CO2 capture and storage (CCS) research program to ensure its viability and long-term safety. Storage of CO2 in deep subsurface reservoirs requires estimates of sustainable fluid pressures that will not induce fracturing or fault reactivation which could cause fault slip. More importantly, fault slip gives rise to seismic waves, which inflict severe damage to the cap rock of the reservoirs and may result in leakage pathways for the buoyant plume and thus compromise the integrity of seal formations. In this study, we generated a numerical model tuned towards conditions usually encountered in the Shenhua CCS demonstration project in Ordos basin. In particular, with the purpose of evaluating the sensitivity of the parameters as well as their relationships with the moment magnitude of the seismicity, a variance-based sensitivity analysis was adopted for importance ranking of the uncertain input parameters of the given model. However, such flow models could involve one or several spatial inputs, for instance, fault dip, distance between fault and the injection well, friction angle of fault, permeability of fault, Young's Modulus of fault, injecting pore pressure and the stress field. Studying the sensitivity to each of these spatial inputs motivated the present work. The results led to the following conclusions: fault depth and fault dip significantly affect the behavior of the fault and the fault slip becomes violent with the fault depth increasing and fault dip decreasing. Furthermore, the results indicate that slip time increases with the fault dip decreasing and decreases with permeability of fault increasing. In addition, the calculation of seismic moment and moment magnitude of an earthquake demonstrates that it rises significantly with the decrease of fault dip and the increase of fault depth, and it decreases with the rising stress field. The results show that variations of the only controllable parameter injection pressure do not show great influence to the fault behavior compared with other geological factors, which imply site selection is extremely important for the CCS projects.

Jan 1, 2015

By Dean Brox

Tunnel boring machines (TBMs) have been used for the construction of various tunnels for mining projects for the purpose of access, conveyance of ore and waste, drainage, exploration, water supply and water diversion. Several mining projects have seen the successful and economic beneficial use of TBMs, and there is an increasing awareness of the benefits of TBMs for mining projects. Key technical considerations for the use of TBMs for the construction of tunnels for mining projects include geological issues (rock type, rock alteration, rock strength, rock abrasivity, durability, ground water in flows), depth of cover and the potential for overstressing/rockbursts, site access and terrain, portal locations, TBM constraints, minimum tunnel size, tunnel support requirements, contractor and labor experience, and project schedule demands. TBMs offer key project schedule benefits with high rates of progress, which is a unique economic advantage recognized for mining projects where timing is of the essence in order to advance mining development and achieve early startup for operations. A thorough evaluation of the anticipated ground conditions should be performed as part of the decision to adopt a TBM for a mining project. Minimum specifications for TBMs are necessary in order to prevent the incorrect type of TBM from being used. Appropriate geotechnical investigations are necessary in order to provide key information on the anticipated subsurface conditions for careful planning and design of the proposed tunnel alignment. The overall site and geological conditions associated with some projects may suggest that it is not appropriate to use TBMs for some mining projects due to a perceived higher risk. Key words: TBM, Tunnel boring machines, Tunneling in mining

Feb 1, 2014

By Kenneth J. Reid, Marian S. Stachowicz

A preliminary evaluation of a new in-stream particle size analyzer has been carried out using materials obtained from a taconite plant in Northern Minnesota. Results are reported for bench scale, pilot scale and full scale tests, the latter being carried out in a taconite plant concentrator. The unit employs a novel scanning laser microscopy principle and details of the equipment configuration and operating principles are presented and discussed. Data acquisition is via an eight channel digital electronic system and particle counts are collected on the basis of reflected light pulse time intervals which are a direct measure of particle size. Output is available as an eight point individual or cumulative size distribution or as computed averages. The practical aspects of sample point location and flow requirements for reproducible results are outlined and discussed.

Jan 1, 1990

By Cengiz Karagüzel, Ömer Canıeren

The mobility of gold and silver metals from refractory ores is very low due to free metal ions in their bodies that bind the transportable and free metal molecules or they are encapsulated in minerals such as sulfides, arsenosulfides, carbonaceous, and clayey materials which make it difficult to extract them. As known from the literature, the enrichment of oxide refractory gold, silver ores, Ag, and Au-rich flotation concentrated from sulfur refractory ores can be leached in the chloride-hypochlorite solutions. In this work, the leaching approach was studied to extract silver ions from refractory ores in the presence of hypochlorite media under high pressure. The mineralogical and scanning electron microscopy analysis of the sample indicated that the silver was encapsulated in barite and quartz minerals in fine sizes. In order to obtain the optimum leaching conditions for the silver ore, the effects of several parameters, namely, temperature, leaching time, NaCl and NaOCl concentration, solid ratio, and particle size on the leaching recovery were investigated in detail. The leaching experiments showed that the highest silver recovery of 62.35% was obtained under the following conditions: temperature of 150 °C, oxygen pressure of 1800 kPa, leaching time of 2 h, concentrations of 2 mol/dm3 and 0.4 mol/dm3 for NaCl and NaOCl, respectively, the solid ratio of 30%, and particle size (d80) 15 μm. The results obtained from this study indicated that the enrichment of refractory silver ores to extract the silver encapsulated in barite and quartz minerals could be possible in the chlorite-hypochlorite under high pressure, a relatively shorter leaching time compared to conventional cyanide leaching.

Jan 28, 2021

By R. B. Anderson

As a part of a Bureau of Mines program on the conversion of coal to liquid and gaseous fuels, the kinetics of the Fischer-Tropsch synthesis on iron catalysts was investigated. Nitrided catalysts were studied at 21.4 atmospheres using feed gases ranging from 2H2+1CO to 0.25H2+1CO, and at 7.8 to 21.4 atmospheres using 1H2+1CO gas. The overall apparent activation energy increased with increasing carbon monoxide content of the feed gas from 19.5 kcal/mole for 2H2+1CO to 23.7 for 0.7H2+1CO. The rate of synthesis with 1H2+1CO feed increased linearly with operating pressure from 7.8 to 21.4 atmospheres. A semifundamental rate equation of the form [r=a'PH2 0.6pco 0.4- ?r0.5PH200.5] was shown to fit the data satisfactorily. The relative usage of hydrogen to carbon monoxide decreased with increasing conversion, passed a minimum, and then increased. Apparently water is the principal primary product and carbon dioxide is produced by subsequent water-gas shift reaction. In another group of experiments water, carbon dioxide, argon, and methane were added to 1H2+1CO feed to a nitrided iron catalyst. Argon and methane were only diluents. Carbon dioxide was a slight inhibitor and water vapor was a strong inhibitor to the rate of synthesis. Water accelerated the water-gas shift and usually increased methane production. Important factors of catalyst geometry in determining rate were found to be particle size and extent of reduction. Apparently the active portion of the catalyst is confined to a layer of 0.01 to 0.02 cm from the external surface of particles. A special solution was made of differential equations relating re¬action at the catalyst surface to diffusion in pores of the catalyst for spherical particles with an active layer surrounding an inert core. The equation derived expressed the experimental data reasonably well. Diffusivities determined by this equation varied from 3 to 24X10-6 cm2/sec; these values are of the same magnitude as observed for the diffusion of gases in liquid. The appendix presents a group of synthesis experiments at pressures of 21.4 to 103 atmospheres. In this range the rate of synthesis on nitrided iron catalysts increased with pressure to the 0.74 to 0.84 power.

Jan 1, 1964

By Debra Satkowiak, Ronald Thomas

The Institute of Makers of Explosives (IME), a non-profit safety and security organization founded in 1913, is known for its industry best practices, Safety Library Publications (SLP), some of which have been incorporated into rules by regulatory agencies. The IME developed the first commercial storage, quantity distance (Q/D) table titled “The American Table of Distances” (ATD). It was developed by IME’s legacy association in 1910 and was originally based on observations of structural damage from 117 accidental explosions involving small to very large amounts of explosives, primarily dynamite and black powder. In 1930, the IME published a book, compiled by Ralph Assheton, called the “History of Explosions on Which the American Table of Distances was Based”. The distance in feet in the ATD were founded on the measurements at which inhabited buildings sustained substantial structural damage from the accidental detonation of explosives. For example, minor damage such as window glass breakage and the “shaking down” of plaster was not considered substantial structural damage. Other damage to property that was readily repairable was also not considered “substantial.” It was concluded that unless some integral portion of the building was damaged, the occupants would not be subjected to serious risks.

Jan 1, 2017

By Michael F. Kitto

The production of sulphuric acid at base metals smelters is predominantly an involuntary activity and now comprises approximately 17% of all-forms sulphur supply in world terms. The majority of elemental sulphur is also produced involuntarily in response to environmental regulations regarding emissions from hydrocarbon processing plants. The paper examines the points of similarity and difference in the sulphur and smelter acid markets, and reviews their interactions. The reasons for the merchant acid market collapse of 1993 are analyzed, and the prospects of a recurrence are considered.

Jan 1, 1996

Profiled on these pages are the eight RMCMI 1997 Scholarship Award winners. All eight winners were present as guests of the Institute at the June convention at Steamboat Springs, Colorado. Each received recognition at the Institute Awards Luncheon Monday, June 30, 1997. Each state vice president served as host for the collegiate winner and his firm provided travel and hotel expenses. In addition to receiving a plaque from the Scholarship Chairman, Alan Czarnowsky, each winner receives $1,000 tuition credit for the coming academic year, as well as transportation, hotel lodging and meals at convention as guests of the Institute. Because this is a continuing award, the winners from the previous year also receive a $1,000 tuition credit in their senior year if recommended by the dean of the college or university and if they remain full time students. A resident from each of the eight RMCMI member states is selected from among Board approved institutions. Criteria for these awards made annually is that the recipient (1) Is a full time sophomore student who will use the tuition credit during the junior year. (2) Be both a U.S. citizen and a resident of the member state. (3) Maintain good academic standing, be pursuing a degree in a mining related field and have an expressed interest in western coal as a possible career path. The scholarship program includes curricula other than in the mining departments, but in engineering disciplines, such as geology, mineral processing and metallurgy. Contributions to this worthy project are tax deductible to each individual RMCMI member or his firm. Through annual donations of $100 or more, the Patrons of the Institute fund the scholarship program. A listing of current donors is found elsewhere in this book. Donations to this worthwhile program are payable to RMCMI Patrons and may be mailed to the RMCMI Office, 3000 Youngfield Street, Suite 324, Lakewood, Colorado 80215. Profiles of the 1997 Scholarship Winners follow. [ ] ARIZONA WINNER C. Travis Naugle Montana Tech - Butte, Montana Travis, the son of Chelsea and David Naugle of Tempe, Arizona is a student at Montana Tech. He is well-rounded with studies, various athletic endeavors, campus D.J. position, and as a residence officer. He is now the Public Relations Director for KMSM-FM radio in Butte, MT. A Tempe High School graduate, Travis plans to work in coal extraction once he receives his Mining Engineering degree. [ ] COLORADO WINNER Suzanne Maddux Colorado State University - Fort Collins, Colorado Suzanne, the daughter of Janet Maddux of Arroyo Grande, CA and Lelen Maddux of Santa Margarita, CA, is the first scholarship recipient at Colorado State University. She is pursuing a degree in Civil Engineering. Since 1992 she has been working with TerraMatrix Inc. in Steamboat Springs and Fort Collins, Colorado which has offered her insight to the western mining industry. She has volunteered with Larimer County Partner (a big sister program) and has continued to be involved in many athletic endeavors.

Jan 1, 1997

By C. B. Clemmens

Accurately predicting ground control conditions before mining requires a comprehensive exploration approach including photogeologic mapping (satellite and low altitude), delta modeling and, particularly, geophysical logging. In situ properties, density; strength indices; grain size; clay content; and aquifer location, can be estimated with this inexpensive technique. Geophysical measurements can be spot-checked by field or laboratory tests on core samples and by hydrologic (pressure) testing. Each phase of drilling should be accompanied by refinement of the delta model, facilitated by log signatures. Measured properties can then be projected into geologically similar areas. A properly planned program will delineate both the "worst-case" and normal support conditions. Suspect areas can be avoided by mine layout and the mine plan can contain support contingencies for anticipated trouble spots.

Jan 1, 1985

By V Mutton, L Potts, D Joyce

This paper describes the method of extracting sill pillars within the underground operation from under unconsolidated mullock fill at the Cracow Gold Mine. This pillar recovery method was initially successfully used to recover sill pillars at Crusader Mine, Western Australia in 2001. Globally significant resources have been sterilised due to the placement of loose rock fill above crown pillars and within adjacent stopes. The method described here offers significant opportunities to increase recovery of sill pillar recoveries.The royal orebody sill pillars at Cracow Gold Mine form a significant resource. Extraction of these pillars needed to be undertaken with minimal ore dilution and maximum ore recovery. The application that was selected to consolidate the loose mullock fill above each pillar used an injection grouting process (Minova FB200).Cracow Gold Mine mining method is bottom up bench mining. The pillars were left within the orebody to allow for stoping to commence whilst the decline was being developed. Due to the remainder of the orebody being extracted the only access to consolidate the backfill was from the sill pillar extraction level. Numerous problems were encountered and overcome from product selection and trial, system of injection to extraction.This pillar recovery process achieved a 95 per cent recovery of the sill pillar compared with an estimated 60 per cent typical for other mining options.CITATION:Potts, L, Mutton, V and Joyce, D, 2012. Pillar recovery at Cracow gold mine using grouted consolidated mullock, in Proceedings Narrow Vein Mining 2012 , pp 179-184 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 26, 2012

By S. P. Singh

"The geological features of a rock mass have a direct influence on its blasting characteristics. It has been observed that perimeter control techniques provide excellent results in massive crystalline formations but may give poor results in weak and or highly jointed formations.A field study was conducted with the objective of understanding the role played by the geological features of a rock mass in producing and controlling blast damage. The field work involved the assessment of blast damage at several operating mines and the blasting of drift rounds in a geologically dominant rock mass.The effect of rock strength, rock quality designation (RQD), joint parameters and hydrogeological conditions on blast damage is described below. The influence of number and thickness of weak layers on blast damage is also discussed below on the basis of quantitative data. In addition, critical particle velocity ranges for damage to different rock types have also been outlined in this paper."

Jan 1, 2001