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By Gregory P. Lorsbach

Significant information about any blast is contained within the seismic signal generated by the blast. In this study, standard digital signal processing techniques are utilized to extract source parameter information from a seismic signal recorded at distances commonly used in compliance monitoring. Specifically, digital seismic data was analyzed using the cross-correladon and autocorrelation functions for the purpose of determining delay timing. The initial results are interpreted to indicate that: 1) Individual delays can be identified analytically but not visually for short delay periods and large source to receiver distances, 2) Delay timing can be resolved to a few milliseconds, and 3) Results can be obtained from data collected at a minimal number of locations.

Jan 1, 1991

By D. A. Holtum

On Tuesday, 10th November, 1987, The South African Institute of Mining and Metallurgy held a colloquium attended by some 120 delegates on 'On-Stream Analysis' at Mintek, Randburg. Mr John Moore, Consulting Metallurgist of Anglo American Corporation of South Africa Ltd, introduced Mr Gene Fivaz, the President- Elect of the SAIMM, who read an address by Mr B.C. Alberts, the current President. Mr Alberts was unable to attend the Colloquium owing to urgent business overseas. Opening The opening address emphasized the important role of minerals in the South African economy. In particular, it was noted that 20 per cent of the work force were employed in the minerals industry or associated industries. In recent years, production costs had risen as a result of inflation, and sanctions had had some effect on the exportation of minerals. Thus, there was continuing pressure on the industry to improve recoveries and increase efficiency.

Jan 1, 1988

By Calvin J. Konya

Many controversies and differences of opinion exist in blasting technology. The primer location in small diameter dynamite columns is an example of one of these controversial areas. It is generally agreed that in rotation firing of small diameter blastholes, primer placement near the bottom of the borehole is beneficial since it reduces the likelihood of cutoffs. The controversy results in the actual location of the primer in the bottom of the blasthole. Some references indicate that the primer cartridge should be the first cartridge in the bottom of the hole, with the cap pointed toward the collar of the hole. Others indicate that performance is improved with no sacrifice in safety by placing a tamped cartridge first in the hole, and the second cartridge being the primer. The following investigation provides some factual data for consideration.

Jan 1, 1980

The passage of a vast array of new State and Federal environmental legislation over the last couple of years has required many mine operators to sharpen their focus on environmental requirements. Established requirements, such as environmental impact assessment, minimising disturbance and rehabilitation must now be complemented by mine environmental management plans. These may not only require regular monitoring of mine operations and detailed forward planning to prevent or reduce environmental harm caused during mine operation, but annual updating. It is likely that in future these plans will be required to incorporate general principles such as pollution prevention, sustainable development, waste minimisation and conservation of biodiversity and ecological integrity.

Jan 1, 1993

By A. Pavlidis

This paper investigates variations of lignite quality attributes with geostatistical methods. The study focuses on lignite from the Southern Field in the Greek province of West Macedonia. The targeted quality variable is the ash water-free content (AWF). A geostatistical model is constructed based on data from 480 drillholes (approximate drill hole spacing of 250m). For each drillhole, the vertical average of the AWF is calculated. The coarse-grained AWF is then modeled as the superposition of a trend surface and fluctuations. The spatial dependence of the fluctuations is modeled by means of the experimental variogram. Kriging estimators are used to determine the AWF values on a rectangular grid, and the uncertainty of the estimates is calculated. Implications of the analysis for the variability of the produced lignite are discussed, and recommendations for additional drilling are proposed.

Jan 1, 2006

In conjunction with steady increases in production levels, longwall operators have applied greater quantities of ventilating air and spray water in an effort to control respirable dust and/or methane. Air velocities greater than 7.6 mls (1500 fpm) have been measured on longwall faces. Operators have expressed concern over the potential entrainment of respirable dust at these high velocities. The greatest likelihood for entraining dust into the high velocity airstream may occur as shields are advanced allowing relatively dry particles to fall from the shield canopy directly into the airstream. Laboratory tests to simulate dust liberation during shield movement were conducted at the Pittsburgh Research Laboratory of NIOSH at velocities ranging from 2.0 to 8.2 m/s (400 to1600 fpm). Airborne dust samples were obtained with personal impactors to quantify the size distribution and concentration of the dust entrained at the various air velocities. Statistically significant increases in both total and respirable dust concentrations were measured as test air velocities were increased.

By V. Matou?vek

The paper addresses pipe flows of aqueous medium-sand slurries at velocities lower than the deposition-limit velocity. Laboratory test results including measurements of particle concentration distributions are used in order to describe a flow with a (pseudo-) linear concentration gradient above a stationary bed. Particle dispersion within the flow is evaluated and a stratification-ratio equation is formulated, estimating a portion of contact load in the flow. The formula is incorporated in the proposed predictive model for the hydraulic gradient for a medium-sand flow above a stationary bed.

Jan 1, 2007

The paper describes a simulating method.for ground water contamination originating from industrial and mining activrty. The finite difference model simulates heat, mass and solute transport. The applied stochastical method for dispersion provides more accurate solution of mass transport modelling. This method gives a more realistic approach of chemical processes in an aquifer depending on temperature.

Jan 1, 1988

Australian mining practice operates at the forefront of technology. In recent times Australian designers, contractors and operators have shown many examples of technical "entrepreneurship" in solving geological mining and metallurgical problems. Developments have occurred in the fields of equipment, processing, operating techniques and training which have relevance to the mining industry in other countries. Our mineral exports play a key role in main- taining the viability of the Australian economy. Although the export potential of our specialised equipment and technology is at a much lower level it is a growth area. The export of our mining technology can continue to be basically the result of individual efforts but the question of whether it would be war- ranted and desirable, to establish a coordinating structure should be examined. Existing and new initiatives by the Federal Government indi- cate the Government's interest in the export of technology. The mining industry should take a proactive role formulating policy and programs within its technical jurisdiction.

Jan 1, 1988

By Vilem Petr

Optimization blast design parameters for rounds used at surface mines, quarries or cast blast has taken on a new importance with the increased the cost of the explosives and electronic detonators. This paper addresses the fundamentals of blast design and optimization explosive energy utilized for fragmentation. This laboratory studies shows that one key variable-the strain energy set up in rock mass by blast vibration – can be used to predict the extent of damage done to the rock strata, the degree of fragmentation of the broken rock, and the velocity of the broken rock. It also shows how the dynamic strength of the rock strata is influence the fragmentation size distribution as well as the blastability.

Jan 1, 2008

By P. Riveros, A. Pratt, G. Deschênes

The effect of pyrite, pyrrhotite, chalcopyrite, realgar and arsenopyrite on gold dissolution in cyanide media was investigated. The cyanidation of synthetic gold ores, in the presence of various concentrations of sulphides, was studied under constant experimental conditions. A mineralogical analysis of the minerals was performed. The leaching kinetics were determined. The negative effect of sulphides on the gold dissolution rate varies with the sulphide mineral, and decreases according to the following order: realgar > pyrrhotite > chalcopyrite > pyrite > arsenopyrite. The chemical characterization of gold and sulphide minerals surfaces using X-ray photoelectron spectroscopy (XPS) was undertaken to identify the mechanisms involved. XPS analysis showed that a passivation layer of sulphides, arsenic or iron compounds may form on the gold surface as a result of the dissolution of the sulphide minerals.

Jan 1, 2002

The Engineering Societies Building is owned by the United Engineering Society which is composed of the American Institute of Mining and Metallurgical Engineers, the American Society of Civil Engineers, the American Society of Mechanical Engineers, and the American Institute of Electrical Engineers, the four national engineering societies known as the Founder Societies. Its erection, and that of the Engineers Club which adjoins, was made possible through the generosity of Mr. Andrew Carnegie, Honorary Member, who in 1903 contributed $1,500,000 for the purpose. The Founder Societies purchased the land on which the Engineering Societies Building stands and the Engineers Club the land for its building.

Jan 1, 1923

By M. McChesney

Modern materials for underground support* by M. McChesney The properties required of a support material for underground tunnels are discussed and, because concrete is both economical and easy to apply, a number of new reinforcing materials for concrete are examined with particular reference to these properties. From about thirty tests on different types of reinforced concrete, it is concluded that the addition of polymer to a concrete does not seem to influence the concrete's post-failure behaviour, and the on'y benefit to be achieved by this addition is to increase its flexibility (or to decrease it, depending on the polymer). Steel fibres tend to increase both the strength and stiffness of the concrete, but polypropylene fibres, although having definite loadcarrying capacities, provide non-stable failure, also known as brittle failure. The best result was obtained for concrete reinforced with steel wire: the post-cracking strength was very good and was maintained for a considerable deformation.

Jan 12, 1976

By J. F. Harvard

We might say that for the metallurgist time "ambles withal," for the mining engineer time "trots withal," and for the geologist, time "gallops withal." And anyone for whom time "stands still withal" does not belong in the mining community today! In this bicentennial year of the United States of America we sense the mystery of time and we feel the pulse of history, especially in our own profession. What was mining like 200 years ago? What is it like today? What will it be like 200 years in the future?

Jan 7, 1976

There are no data available of shipments until 1858, and then estimated, when railroad service became available. By reason of the iron made in the county, and the large amounts of salt, the tonnage used locally was quite large, and until 1860 these are estimated from the probable salt and iron production. After 1859 the tonnages shipped by rail are partly estimated from the total shipments of the Allegheny Valley Railroad from four counties. It is believed that the totals are below, rather than above, what the actual production was. While considerably larger for the same years than figures given by the Secretary of Internal Affairs and census reports, these data were always too low in those days, partly because of lack of facilities for gathering them, but more largely because of the strong prejudice existing in those days against furnishing such data to any governmental agencies.

Jan 1, 1942

By P. C. van Aswegen

Owing to the strategic value of organic solvents, an investigation was conducted on the reduction of solvent losses at the Buffelsfontein solvent-extraction plant. It was established that the major cause of the high solvent losses was the high content of suspended solids in the uranium pregnant solution. To improve the clarification of the pregnant solution, it was decided to replace the conventional sand clarifiers that were being used at that stage. After pilot-plant tests had been conducted, a circulatorclarifier 16 m in diameter was installed to treat 9000 m3 per day of pregnant solution containing approximately 500p.p.m. of suspended solids. The clarifier was commissioned successfully, and yielded an overflow containing approximately 80 p.p.m. of suspended solids compared to the previous value of 250 p.p.m. This reduction in suspended solids immediately resulted in a decreasing trend In losses of organic solvent, finally yielding a reduction in these losses of approximately 50 per cent.

Jan 1, 1983

By H. J. Sohn

Systematic studies were carried out on the adsorption of the silver thiourea complex on activated carbon. The experimental isotherm data fit the Freundlich isotherm equation. The adsorption rates increased with increasing temperature and decreased slightly with the increase of free thiourea concentration. The concentration of sulfuric acid had little effect on the adsorption rate. Adsorption kinetics correlated well with the Elovich equation, indicating adsorption is the rate-determining step.

Jan 1, 1987

By M. J. Gouws, T. P. Knoetze

The spontaneous combustion of coal and the explosion of coal dust are two phenomena that were identified by the South African mining industry as requiring investigation. Research contracts were awarded to the G.P. Badenhorst Research Facility of the CSIR and the Department of Mining Engineering of the university of the Witwatersrand by the now defunct National Energy Council. Both projects entailed tests on numerous coal samples in specially designed apparatus. Since the completion of the project, attempts have been made to predict experimental results without incurring the cost of performing experiments. This paper describes predictive indices, based on routine laboratory tests, that were developed by the different research teams for their particular projects. A comparison of the results obtained by applying the spontaneous combustion liability index and the explosibility index to common coal samples indicates that, in general, propensity to spontaneous combustion and explosibility exhibit an inverse relationship. A brief overview is given of some major South African coal-mine disasters.

Jan 1, 1995

Univ of Alabama-University, Alabama-Mining and Metallurgical Society William L Mason, Faculty Sponsor, E C Wright, Dept Head Univ of Alaska-College, Alaska-Mining Society of the Univ of Alaska Douglas W Huber, Faculty Sponsor, E H Beistline, Mining & Metallurgy Dept Head, Troy L Pewe, Geology Dept Head, James Crawford, Chapter Counselor Univ of Arizona-Tucson, Arizona-Miners Society Willard C Lacy, Faculty Sponsor, J D Forrester, Mining & Metallurgy Dept Head, F W Galbraith, Geology Dept Head Univ of California-Berkeley, California-Mineral Technology Association H E Hawkes, Faculty Sponsor, Joseph A Pask, Dept Head

Jan 1, 1959

Kennecott Copper Corp. has sub- mitted a proposal to the U. S. Atomic Energy Commission for a joint experiment to determine if a contained underground nuclear explosion can be used to fracture a low-grade copper ore deposit to recover the copper by in-situ leaching. If authorized, safety and technical studies in the field would be undertaken to determine whether such an experiment could be conducted with full protection for public health and safety. The proposed experiment, known as "Sloop," would be part of the AEC's Plowshare Program to develop peaceful uses of nuclear explosives. As now visualized, the project involves the detonation of about a 20-kiloton nuclear explosive at a depth of 1200 ft.

Jan 11, 1967