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By V. J. McSweeney

This paper is directed at interested parties outside the Beach Sand Industry : the scope is quite broad. The geomorphology described is a successful working hypothesis which guided the author during prospecting and pegging campaigns : the author is not an expert in this field. The test data used in the text, for illustrative purposes, is original and may constitute a contribution to the state of the art. The operation- al and design philosophy embodied in the text is personal and describes the author's methods : all practising exponents would differ in some degree amongst themselves on these subjects. In this paper, no criticism of any existing operation or brand of equipment is intended and names are used to maintain a real contact with the subject matter. The author believes that the operational and design techniques evolved in the Beach Sand Industry under continual duress, have a wider application in the mining industry. This glimpse of the Industry is intended to enhance the respect for the present and past members. Space does not permit individual acknowledgements.

Jan 1, 1982

Continuous remote sensing of air speed In underground mine airways. Approach An ultrasonic technique measures a form of air turbulence which is proportional to air velocity. How It Works The stainless-steel enclosed transducer consists of a sensing head with circuitry, and a telemetry card. The sensor uses a patented ultrasonic technique to measure a form of turbulence created In the air. This turbulence, known as vortex shedding, is related to the air speed through the sensor. Air flowing past a cylindrical post creates vortices which flow down the air stream on both sides of the post. Pulses from an ultrasonic transmitter pass through the vortices to a receiver; the effect of the vortices on the pulses is a measure of air velocity. The transducer contains a telemetry card, known as an accessor, which transmits reports on air velocity through a pair of wires to a monitoring system. The accessor contains an analog-to-digital converter and digital telemetry circuitry required for computer system operation. The transducer does not contain any read-outs or alarms and air velocities are displayed by means of a centrally located

Jan 1, 1982

By Alan Rhodes

This study is initiated to investigate the efficiency of separation of mineral slimes using electroflotation as compared to that of column and conventional flotation techniques. Important parameters such as collector concentration, pH, current density, aeration rate, etc., have been studied. The results indicate that electroflotation can be used more efficiently in processing rutile slimes (10 µ) under certain operating conditions.

Jan 1, 1982

By Michael J. Pratko

The bulk handling industries have long been plagued with problems in their attempt to obtain one of their major goals - the maximum efficiency for which a bulk handling flow system was designed. Mentor Dynamics Ltd. is an international firm with offices in Canada, Japan, and the United States. Mentor Dynamics Ltd. is in the business of solving the "why not" of a system and engineers the solution for the problem. Studies of the varied difficulties encountered with bulk flow systems indicate that 90% of all flow problems fall into one or more of the following categories: abrasion, impact, sticking, and/or inadequate design. These problems can occur with a myriad of bulk solids: coal, gypsum, aragonite, phosphate, fly ash, ore. Solutions to the problems are as varied as the problems. The proper lining material, ceramic, urethane, rubber, and/ or ultra high molecular weight polyethylene, must be coupled with the correct fastening system, annular ring and 'F' cap, weld washer, button head fastener, weld studs and/or nuts and bolts.

Jan 1, 1982

By J. J. Pavlica

Grinding in steel mills adversely affects the flotation removal of pyrrhotite from magnetite ores. To elucidate the effect of grinding media on the floatability of pyrrhotite, rest potential and short-circuit current measurements were made on electrode combinations of pyrrhotite-mild steel and pyrrhotite-stainless steel. Galvanic contact of pyrrhotite with mild steel increased the rate of surface reactions on pyrrhotite in air-exposed and oxygenated solutions. It was postulated that the formation of ' an iron hydroxide coating on the pyrrhotite adversely affected its floatability. Its formation was minimal when pyrrhotite was contacted with stainless steel. Fine magnetite particles caused slime coating on pyrrhotite surfaces by magnetic interaction and impaired the flotation of pyrrhotite.

Jan 1, 1982

Used in conjunction with geology and geophysics, geochemistry provides powerful exploration tools of special relevance to Australian environments. New methods are needed that will confront the forthcoming emphasis on locating concealed orebodies. Deep weathering is conducive to techniques using groundwaters or gaseous emanations as sample media. Increasing use is anticipated for isotope measurements and for recognition of country rock characteristics that denote proximity to mineralization. Improvements in the sensitivity, reliability and portability of analytical instruments will underpin the contributions of geochemical methods to future mineral exploration.

Jan 1, 1982

By M. L. Jeremic

"The syngenetic and epigenetic mechanics of sedimentation and deformation of coal seams resulted in various types of internal structure, as listed below:TYPE I-massive structure with evenly distributed coal constituencies of integrated mechanical properties.TYPE II-broad-banded structure, with bright and dull coal bands of differential mechanical properties.TYPE III-heterogeneous structure, with sheared coal bands and partings of sectional mechanical properties.TYPE IV-contortional structure, with refolded coal layers and deteriorated mechanical properties.TYPE V-porous structure of orogenically crushed and pulverized coal, with disintegrated mechanical properties.The study suggests criteria for the estimation of coal seam internal structure (gamma-gamma density log and cracks density log), which might be related to the evaluation of strata stability and coal mineability.IntroductionIt is common knowledge that coal seams have various internal structures due to different syngenetic and epigenetic events. Investigations of the internal structure of coal seams have been carried out in the coal fields of Western Canada, as follows: geological field studies of coal-bearing strata;?,geophysical borehole surveying studies;?,geological borehole logging and crack density;?,underground phenomenological studies of mine structure;?,chemical coal analysis; and?,mechanical testing of coal samples.These investigations eliminated a large number of criteria previously established for the estimation of coal seam internal structure and indicated that, from an engineering point of view, only two of them are sufficient:(I) density of seam profile (inferred from gamma-gamma log);(2) density of crack s (inferred from geological log).On the basis of these criteria, five main structural types of coal seams have been classified, which might be related to mechanics of deformation and ' failure of mine structures."

Jan 1, 1982

By Tadashi Nishida

Subsidence due to mining caused various kinds of damage to the surface structures, and actually great deal of mining damage becomes the severe social problem at some time in many coal fields, but the most of mining damage was restored at present. Recently, the effect of old coal working on the deformation of newly constructed structures has become into question, because it was obliged to plan many engineering structures in old mining areas for the shortage of adequate construction sites and the difficulty of getting location. That is, building, dams, bridges for railroads and highway, power plants, tunnels, storage tanks and so, have to be built on the ground which has old coal working.

Jan 1, 1982

By T. Takamori

This paper reviews the present status of coal preparation in Japan concentrating on the process in coal cleaning and waste water treatment. This paper also discusses recent topics on maintenance, automatic control, raw coal management, etc.

Jan 1, 1982

By David B. Gladwin

Regional characteristics in the coal resource base have resulted in application of different mining methods across Canada. Longwall methods predominate in eastern Canada, whereas open pit, hydraulic and room-and-pillar methods are utilized in the west. Both provincial and federal agencies have regulatory responsibilities and both also share in the development of R&D programs. This paper outlines the scale and scope of the various agencies involved with health and safety R&D in our expanding coal mining industry. Specific R&D activities in ventilation, dust control, explosion hazards, tunnel boring, strata control and truck braking, which form part of the national program, are outlined.

Jan 1, 1982

By Byron R. Berger

Epithermal Ag-Au deposits form at low to moderate temperatures in near-surface environments. Historically, these deposits have been the source of high-grade ores. Increases in the market prices for gold and silver make lower-grade ores economically viable when available in large tonnages. Both the high-grade and bulk-tonnage ores are a consequence of the same processes, and general models of epithermal systems can be useful in the search for new precious-metal resources. A detailed study of deposits at Round Mountain, Nevada; Balei, Russia; Creede, Colorado; Guanajuato, Mexico; and Chanarcillo, Chile, indicates that the hydrodynamics of the fluid systems as determined by fracture geometries, the permeability, and composition of the host rocks are the key factors in the creation of both high-grade and bulk-tonnage epithermal deposits. End-member models that explain the range of observed deposit characteristics are: (1) the hot-springs deposition model; (2) the stacked-cell convection model (where mineral deposition occurs laterally along the interface of two partially separated fluid reservoirs); and, (3) the closed-cell convection model (where deposition occurs in vertical zones due to the relatively unimpeded vertical flow of hydrothermal fluids). Boiling and fluid mixing appear to be agents of precious-metal deposition with the self-sealing of the hydrothermal system being an important adjunct to boiling. Imaginative application of model concepts in exploration has led and can lead to the discovery of new high-grade and/or bulk-tonnage precious-metal deposits.

Jan 1, 1982

By E. Topuz, S. S. Bhamidipati, M. Bartkoski

Air Leakage in underground mines is the most common cause of inefficient distribution of ventilating air. Depending upon various factors, more than one half of the fresh air entering a mine short-circuits to the return airways before reaching the working faces. Consequently, large leakages create an additional demand for increased intake air, which substantially affects the efficiency of a mine system. This paper deals with the identification of the physical variables of air leakages and offers an overview of the methods of measuring leakage.

Jan 1, 1982

By B. R. Waples

The first reaction in organizing a project of magnitude is that it's the same as smaller projects -- just bigger. This is not totally correct. The industry's record of completing big-money jobs on time and within budget is not outstanding. From a personal point of view, my question is: What is the project size at which controls are lost? Is it controls? Is it the number of pieces of equipment? Is it the number of decisions to be made? The slowness of communications? Or is it a combination of all of these? In working on multimillion-dollar jobs, the percentage of overrun seems to be lower or show an underrun when the following basics are followed: 1) Preplanning is intensified 2) Data gathering is complete 3) Approach is optimized 4) Planning is realistically scheduled 5) Changes are minimized 6) Decisions are expedited

Jan 1, 1982

By K. K. Bhattacharyya

In the Gulf Coast area lignite deposits occur in Texas, Louisiana, Arkansas, Mississippi and Alabama. Lignite has been mined in Texas since the early 1800's reaching a production of over 900,000 metric tons (1 million short tons) in 1910. With the availability of inexpensive oil and gas, production fall to as low as 16,000 metric tons (18,000 short tons) by 1950 (Henry, 1976). With the advent of the oil and gas shortage in early 1970, lignite production began to increase again. The purpose of this paper is to discuss the geotechnical considerations of mining lignite in the Gulf Coast area, particularly Texas and Louisiana. Lignite deposition occurs in unconsolidated sand, silt and clay environments. Extensive sand units saturated with water may be present within the potential mining depths. This paper describes the geotechnical considerations for designing a surface mine in this geographical area. These factors include geology, hydrology, mining method, and equipment utilization.

Jan 1, 1982

By R. W. Hodder

"Archean lode gold deposits of both vein and chemical sedimentary types typically have major enrichments of certain rare elements, including Au, Ag, As, Sb, B, W, Se, Te and Bi, coupled with low or negative enrichments of the more abundant and mobile base metals, Cu, Pb and Zn. On the other hand, in massive base metal sulphide deposits Au, Ag, Cu, Zn and in some instances Pb are all enriched by a factor of 200 to 2000 t:'Jf'1pared to background and there is no large separation of gold relative to the base metals.The fluids from which gold was precipitated in veins were at temperatures of 320 to 480°C, at lithostatic pressure, had significant C02, and Na """" K; whereas the fluids which generated base metal deposits were at 250-300°C, at hydrostatic pressure, had C02 < < H20 and Na > > K.Many lode gold deposits are characterized by K, C02 and Si additions to their enveloping rocks, whereas base metal deposits typically have a fixation of Fe, Mg, Si and S in footwall rocks. Lode gold deposits may also have a relatively large halo of low-temperature oxidative, sadie spilitization in enclosing volcanic rocks, where seawater has later streamed into cooling stocks or flows that have initially acted to focus gold mineralizing fluids along thermal contraction fractures. The submarine environment is one hydrologically appropriate for the mixing of two initially independent hydrothermal systems, and the blending of their separate characteristics. Hence, lode gold and base metal massive sulphide deposits appear to be products of two distinctly different crustal and hydrological regimes. The former involves a high-temperature, high-pressure discharge of fluids which probably were generated during dehydration accompanying burial and progressive accumulation of volcanic-sedimentary sequences, with an additional influence of marine water in the near-sea-floor environment. The latter represents thermally driven convection of ocean water at lower temperatures and under hydrostatic conditions.Auriferous fluid systems with only minor base metal content could plausibly be generated during dehydration accompanying burial and metamorphism, when the water-to-rock ratio is low and halogen availability is limited by crustal abundance (- 60 ppm Cl). These two factors may constrain the uptake of the abundant base metals into fluids, but the solubility of rare elements is not constrained by limited fluid; and preferential uptake of Au along with other rare elements may be promoted if such elements compete more successfully for the limited halogens than the base metals, and/or have an alternative complexing agent such as CO or C()j-."

Jan 1, 1982

By Fred H. Lightner

The feasibility evaluation of the Borealis project of Houston International Minerals Corporation (HIMCO) was initiated in October of 1980. The operation of the Borealis Mine and heap leaching plant began in late 1981. In order to achieve the rapid development schedule several items were necessary: 1) Pre-planning of environmental requirements and early study of key issues. 2) Adoption of conservative design criteria. 3) Coordination and cooperation between HIMCO and regulatory agencies. 4) Adoption of specialized engineering and construction procedures. 5) Careful evaluation of owner project management philosophy.

Jan 1, 1982

By George R. Stephans

The Climax Mine is a panel caving mine which has had a long history of incidents of severe ground control problems. The nature of the ore deposit, which lends itself to the caving meth- of of production, a1 so makes the mine susceptible to large scale stress concentrations which are referred to as ?weight? problems. These problems have increased with increased production and also with expansion to deeper mine levels. During the past twenty years the mine has had to learn to cope with these problems in order to remain in operation. A number of practical guidelines and useful techniques have emerged from these efforts. The purpose of this paper is to share a few of these ideas. The Mine is located near Leadville, Colorado on the continental divide at an elevation of 3450 meters. The ore body is a large low grade deposit of disseminated molybdenum sulfide. It measures about 1200 to 1600 meters in diameter and it had an original depth of about 660 mters. The Mine has been in operation since 1918 and the massive nature of the ore body together with its blocky, highly fractured condition made it natural for the caving system to have been adopted for production at an early date. Open pit mining was started in 1973. The total plant has a capacity of more than 50 thousand tons per day, and more than 400 million tons of reserves at an average grade of 0.310 percent molybdenum disulfide remain to be produced.

Jan 1, 1982

By Bruce R. Lipin

Chromite, the only ore of chromium, occurs almost exclusively in mafic-ultramafic rocks and their weathering products. However, not all kinds of mafic-ultramafic rocks are favorable hosts for possible low-grade chromite deposits. For instance, chromium-bearing basalts are not favorable because they commonly contain < 0.3% Cr2O3, and chromite is almost always less than 50 um in diameter, if it is present at all. Chromite-bearing ultramafic rocks in stratifonn and alpine complexes tend to be either ore grade (> 25% Cr203) or very low grade (< 2% Cr203); intermediate rocks are scarce. In most complexes large tonnages exist only in the < 2% Cr2O3 group and the composition of the chromite is commonly unsuitable for metallurgical use. Some nickel laterite districts contain more than 108 tons of material with 2.0% to 5.5% Cr2O3, and hence, chromium could be a byproduct of nickel in some laterite districts.

Jan 1, 1982

By Satyajeet Ghosh, Edward F. Glynn

Many of the proposed techniques for calculating the reliability of rock slopes utilize Monte Carlo simulation. Monte Carlo approaches are attractive because they provide means of solving probabilistic problems with deterministic algorithms. One disadvantage shared by all simulation-based stability analyses is that they assume all the random variables are independently distributed. The paper focuses on the independence assumption and examines the effect of correlation on the probability of failure. In particular it considers the influence of possible (albeit hypothetical) correlation between joint attitudes [(8)] and joint friction angles [($)]. The study indicates that neglecting correlation can introduce significant errors into the reliability computations. With a modest positive correlation between [8] and [$] the error can lead to a 100% overestimate of the probability of failure.

Jan 1, 1982

By R. B. Hawkins

The discovery of the gold deposits of the Jerritt Canyon district and the construction of the E. R. Bell Mine is one of the significant mining developments in the United States during the past ten years. This mine will exploit one of the larger deposits of disseminated gold presently known, with proven, recoverable reserves in excess of 67.6 million grams of gold. Interest generated by the success of this project has contributed greatly to the tremendous resurgence in exploration for disseminated gold deposits in Nevada and throughout the west. The Jerritt Canyon project, including the Bell Mine, is a 70/30 joint venture between Freeport Gold Company and FMC Gold Incorporated, both of which are wholly owned affiliates of the respective parent companies, Freeport-McMoRan, Inc. and FMC Incorporated. Under the terms of the joint venture agreement, Freeport Exploration Company, another Freeport-McMoRan affiliate, manages the exploration and pre-mine development. Drilling, design, construction and management of the Bell Mine are provided by Freeport Gold Company.

Jan 1, 1982