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By D. R. Reeves

This paper describes the geophysical Jogging of coal that is being carried out for the National Coal Board in the United Kingdom. An explanation of the technique is given and results are presented showing estimations of seam thickness to within ±0.5 in. and ash content to accuracies of ±2.5 per cent. The basic method of interpretation is outlined and some conclusions regarding the conditions of roof and floor material which may be deduced from the logs are explained. An indication of future developments in this field, including the identification of coal type and moisture content, is given.

Jan 1, 1971

"The asbestos mining industry in the Eastern Townships of Quebec has early recognized the undesirable side-effects associated with mineral production, such as air pollution, noise and unsightly waste dumps. In order to efficiently achieve the industry's aim of eliminating or minimizing these objectionable features of mining, all of the asbestos producers in Quebec interchange information, knowledge and design dealing with the environmental control measures through the Environmental Committee of the Quebec Asbestos Mining Association.The paper describes what has been done and what is planned for the future in the various problem areas, such as control of dust emitted during the open-pit drilling operation, control of dryer stack emissions, control of the environment in ore, fibre and tailings handling operations, rehabilitation of the countryside covered by waste dumps, and many others."

Jan 1, 1971

By James B. Fletcher

The Miami mine is located near the town of Miami, Gila County, Arizona. The Miami mine started mining in 1910 and finished in July, 1959. The orebody was divided and mined as follows: Tons High Grade 24,400,000 - Top slicing, sub-level caving, etc. Low Grade 105,100,000 - Block caving Mixed ore 9,800,000 - " Low Grade #2 13,100,000 - " Total Mining 152,400,000 GEOLOGY Ore minerals are largely in pre-Cambrian Pinal schist intruded by tertiary Schultz granite porphyry and covered to some extent by Quarternary Gila conglomerate. The structures are highly faulted and shattered. The Miami fault on the east cuts off the ore and the Pinto fault on the southwest caused re-oxidation of enriched sulphides producing mixed ore. MINERALOGY The chief mineral is chalcocite, with chalcopyrite, bornite, covellite, malachite, azurite, chrysocola, cuprite, native copper, and molybdenite as minor minerals. The ore minerals occur in seams, veinlets and disseminated particles. In block caving there is always some dilution, and drawing of ore stops when the grade drops past an economical point. This results in a small amount of copper left in the stopes below the capping. There is some copper in the capping, probably below 0.03% or less than 0.6 lbs. per ton. Over the low grade #2 orebody and portions of the high grade there was an oxide capping which was not mined. The crushed pilars are another source of copper. The leaching at Miami is an attempt to recover this last remaining copper of a worked-out mine. The enrichment at the Miami mine had gone more nearly to completion than most ore bodies in the southwest. There is practically no pyrite in the capping and very little in the ore.

Jan 1, 1971

By William H. Pelton

The presence of high-grade massive sulphides near York Harbour, Newfoundland has been known since the turn of the century. In the early 1900's a small, massive-sulphide deposit was worked by conventional hand methods and yielded about 100, 000 tons of high grade copper-zinc ore. Since that time, a number of mining companies have held options on the property and an exploration adit was driven along the fourth level of the original mine. Underground drilling revealed several additional massive sulphide lenses in the range of 10, 000 to 60, 000 tons (Fig. 1). The problem facing Long Lac Mineral Exploration Ltd. when they undertook an option on the property in 1969, was to outline any possible extensions to the known sulphide lenses which were outside the reach of underground drills and to search for new ore deposits which might double the known reserves into a feasible project for development. GEOLOGY AND PHYSICAL PROPERTIES: The geology is typical of many massive sulphide deposits within volcanic rocks in the Canadian Shield. The sulphide pods appear to occur along a complex andesite-basalt contact. Identification of the two volcanic types is difficult since they are almost the same colour. The most direct means of identification is by the slight difference in their magnetic susceptibilities. Pyrite, chalcopyrite and sphalerite are the main minerals in the sul¬phide lenses. The ore is massive, differing in density from the host rock by at least 1.0 gm/cc. There is little pyrrhotite or magnetite associated with the sulphides, so there is no appreciable difference in magnetic susceptibility between the sulphides and the basalt. Also, there is no alteration halo around

Jan 1, 1971

By W. Dingley, G. R. Hoey

"Thirteen Canadian sulphide ore mines were surveyed for corrosion control. The mines visited were a small, yet representative, proportion of this segment of the Canadian mining and metallurgical industry. Information on metallic corrosion and methods used to control it in underground workings and mills was gathered (a) by discussing corrosion problems with company personnel, (b) by examining equipment and structures during under-ground and mill tours, (c) by photographing corrosion sites, and (d) by collecting and analyzing mine water samples.The corrosion survey, which is summarized in the re-port, leads to the following general conclusions. Mine environments are corrosive, particularly when the mine w1a-ter is acidic. Because of a lack of good corrosion control measures, excessive deterioration of equipment due to corrosion occurs in mines. Mill environments are also corrosive, but in some cases good preventive measures are being taken to effectively control corrosion losses.Ways to reduce corrosion losses in sulphide ore mines and mills are discussed. The main areas for more corrosion research and development are selection of materials of construction, protective coatings, cathodic protection, inhibitors, equipment design, and mining and milling practices."

Jan 1, 1971

By C. Dan Kealy

Recent antipollution legislation for the control of mine tailings and waste-water has required an increasing number of tailings ponds. Many of these new waste-retention ponds are being constructed in congested locations, or the older ponds have reached such a size that--if failure occurs--they pose a threat to human life and public property. Although the typical tailings-disposal embankment represents--to the casual-, observer or the economy-minded mine official--a rather ugly but benign and stable pile of waste, they are in fact an extremely sensitive structural mass, retained behind the frailest of dikes. Failure of the waste mass requires only a minor change in water retention or weather conditions, erosion or piping of the ground strata, shifts in load or slight earth tremors. When failures occur, the results can be disastrous. In the U.S., we have been fortunate that, so far, pond failures have not caused loss of life. Thus, failures in this country have attracted little public attention. Present tailings-pond construction methods used by the mining industry require the barest money investment, and little engineering effort. Unfortunately, this superficial approach may increase short-term profits, but the practice may be conducive to the construction of needlessly weak structures. In coming years many of these designs will probaly become corporate liabilities. A typical pond is portrayed in Figure IA. This particular pond in Arizona is 1 mile long and 3/4 mile wide. Illustrated in Figure lB is a representative pond in cross section. This paper in concerned with two basic features common to all tailings disposal: (1) location of the phreatic surface within a tailings-pond embankment because of its influence on embankment-slope stability, and (2) prediction of

Jan 1, 1971

By Theodore M. Olson

The Washington State Highway Department consists of seven geographic dis¬tricts. District offices are located in Seattle, Wenatchee, Olympia, Vancouver, Yakima, Spokane and Bellevue. District is covered from the Spokane office, and is responsible for the six counties in the northeast corner of the state (Fig.l). It is bordered on the north by the International Boundary, on the south by the Snake River, on the east by the Washington - Idaho border, and on the west by a north-south line thru Lake Roosevelt. The landslides to be discussed in this paper are at Colfax, Washington, which is located in the southeast corner of the district. The town of Colfax is situated in a narrow valley eroded into the Tertiary volcanic basalts by the Delouse River. The valley walls are steep and generally colluvium mantled. State Highway 1°c, from Spokane to Colfax, descends into the valley from just north of Colfax on a bench cut into the valley wall. The highway department designed a widening project to increase the misting two lane roadway to three lanes, thus providing a passing lane for uphill traffic. The third lane was constructed as a cut section for the entire length. Construction excavation was begun at the top of the hill in silts of eolian origin. Proceeding downhill, excavation encountered three individual basalt flows with two zones of palagonite tuff separating them. The upper palagonite zone was dry, and excavation proceeded across this zone with no mishaps. The lower palagonite zone carried considerable groundwater. As excavation crossed the lower zone landsliding became contemporaneous with excavation, due to removal of toe of slope and saturated conditions. Remedial measures for landsliding consisted of designing shot rock buttresses across the palagonite zone and also the installation of horizontal drains to reduce hydrostatic pressure.

Jan 1, 1971

By L. A. Neumeier

The Bureau of Mines evaluated the properties and anisotropy in properties of rolled Zn-Ti and Zn-1.0 wt pct Cu-Ti alloys containing up to 0.36 wt pct Ti. Finish rolling was at varied temperatures to total reductions as high as 92 pct. Alloy properties are very sensitive to various combinations of composition, rolling temperature, and reduction. Properly rolled Zn-1.0 Cu-Ti alloys are superior in strength to Zn-Ti alloys. Conditions are described that lead to best tensile properties. Creep resistance for Zn-Ti alloys decreases with increased rolling temperature when finish rolled to 92-pct total reduction: but not when finish rolled to 33- or 67-pct reduction. Creep resistance for 7n-1.0 Cu-Ti alloys improves with increased rolling temperature to about 480° F. Heavily cold-rolled Zn-1.0 Cu-Ti alloys have fine grain sizes and poor hardness, tensile, and creep properties, but high ductility. Thermal expansivity is markedly affected by the copper addition. Data show the anisotropy of tensile, creep, and thermal expansivity properties. Large idiomorphic crystallites of TiZn15 appear in both Zn-Ti and Zn-Cu-Ti alloys when more than about 0.2 pct Ti is present. A new Zn-Cu-Ti intermediate phase was also identified. Empirical equations are presented relating creep rates with major process variables.

Jan 1, 1971

By Manuel Gomez

Dehydrogenation factors, proximate analysis, and ultimate analysis were examined as predictors of the low-temperature -carbonization properties of coals varying in rank from lignite through anthracite. All factors studied contributed to reduction in variance of the sample populations investigated. Response surface regression models based on variables from proximate and ultimate analyses of coal were constructed for eight low-temperature carbonization assay product and gas component Fields. These models were tested with independent samples that included drill cores, sized fractions, petrographic fractions, and run-of-mine coal. The models developed were used to predict low-temperature carbonization yields or coals from major fields of Wyoming. This information was cast in the form of contour plots describing the potential low-temperature carbonization product yields of Wyoming coals and the properties of the resultant char or coke. The variables used as input v the models may be measured and collected during exploration; thus, the carbonization properties of a seam can be determined in advance of mining. The information presented in this report is useful in that it broadens the deciionmaking base for management when either mine locations or coal conversicl plant sites, or both, are being considered.

Jan 1, 1971

By Lawrence A. Garfield

From the bottom of a shallow fissure the near-naked man-animal hacked out a hand-sized chunk of the red rock-like material which, when beaten between other rocks, could be drawn out to the thinness of a flint edge. Unlike flint, however, it did not shatter when, as the point for a spear or arrow, it went wide of its mark and fell amongst the rocks or tree branches. For this reason and others, the red rock- like material was specially sought and much time was spent in trying to break it from the real-rock in which it grew. Only infrequently was a chunk broken free and in this area many hours had been spent to win but a few fragments. What luck then, to remove so large a piece where before nothing but real-rock dust formed whenever the stone hammer hit. Why did this happen? Did yesterday's food-fire, burning on top the red rock, loosen its hold on the real-rock and cause it to break free when struck with the stone hammer? It is not a matter of recorded history that the first heat assisted extraction of native copper from country rock occurred under the circumstances or in the manner related but it is known that crude mining operations using these techniques were conducted by primitive man. In this way the first mineral production may have been achieved and the original example of rapid excavation unknowingly given to the world. Rapid excavation is not a method of removing rock or ore from an insitu condition nor does the term refer to a type of equipment which is specifically employed in mining and underground construction. It is, rather, the nomenclature currently popular in industry-primarily in underground construction- relating to a comparative rate of performance.

Jan 1, 1971

By A. D. Pernichele

Four types of slope failures in waste dumps are recognized; debris flow, foundation failure, edge slump and blowout. The first three types, although at times causing considerable damage to property and interfering with mine operations, are not usually dangerous to personnel because of their slow rate of movement. The fourth type, the blowout, is considered to be the most dangerous because of its explosive mode of failure and lack of forewarning. The December failure at Verona dump is presented as an example of a blowout. Data from piezometer holes indicate that the blowout was due to perched leach solutions near the face of the dump. The level of water in this zone is very closely related to the rate of leach water application on the dump. A detailed analysis of core samples indicated that the impounded water was due to a zonal accumulation of Jarosite which is associated with a buried dump surface. Drain holes proved successful in controlling perched leach solutions in the critical zone near the face of the dump. Monitoring of the water level in the perched zone is considered essential in preventing blowouts. The use of drain and piezometer holes has allowed an increase in the rate of water application on the dump while preventing additional failure.

Jan 1, 1971

By W. P. Dyrenforth, W. E. Horst

Although, separating or concentrating minerals, based on differences in. their magnetic properties has been practiced for years1 the early industrial applications of magnetic separators were involved with the most highly magnetic materials. These early separators were used to concentrate magnetite, separate metallic iron from furnace products, and separate iron and brass turnings. Next, the addition of a pretreatment operation, such as roasting or calcining, to transform certain iron-bearing minerals into a highly magnetic compound that could readily be separated from the altered mineral mixture using existing magnetic separation machines was added to the flowscheme. As the number of magnetic-separator installations grew, steady development of better equipment evolved including the design and implementation of induced magnets having high-intensity fields, These developments of course greatly expanded the field of magnetic separation and made it possible to commercially separate or concentrate very weakly magnetic minerals which previously had been considered as nonmagnetic minerals. A number of different designs of magnetic separators were well developed and the unit operation of magnetic separation was gaining wide acceptance in mineral processing operations when two events occurred that dampened these developments. First, the Mesabi iron range with its direct-shipping iron ore was discovered and placed into operation. This of course significantly reduced the need for magnetic separation to meet the raw material requirements of the iron and steel industry. Second, the advent of selective froth flotation, was so successful in solving many mineral process problems that electrical concentration techniques being developed at that time, including magnetic-separation methods, were either terminated or received low priority ratings. During the past two decades interest has been renewed in the use of electrical concentration methods to solve mineral separation problems. As the direct-shipping iron ore reserves are depleted more emphasis has been placed on magnetic upgrading of lower value iron ore available throughout the world. In addition, magnetic separation techniques have found numerous applications in the non-metallic and industrial minerals industry to supplement froth flotation and thus add to the variety of beneficiation methods available.

Jan 1, 1971

By John Mitchell, C. C. Hanninen, L. D. Clark

INTRODUCTION Certain rock types can be fractured thermally by spallation and thermal cracking. Spalling occurs in the regions subjected to thermal shock temperatures and cracking takes place in the adjacent cooler regions. The analysis of the heat-affected zones requires that heat transfer calculations be made where the thermal conductivity of the rock is a function of temperature and direction. Generally, accurate thermal conductivity data is not available for the high temperatures and rise rates associated with most thermal rock breaking methods. This paper describes a method for determining the thermal conductivity of an orthotropic material whose conductivity is a linear function of temperature. The necessary data is obtained from one test which makes it especially useful for in situ applications. The properties data are determined through an iterative process of comparing theoretically computed values of temperature for assumed conductivity parameters with data measured in the laboratory. The conductivity of the rock is determined when the results of the assumed parameters yield computed temperatures which agree with those obtained experimentally. Transient temperatures are computed using the explicit numerical method at given points in a three-dimensional semi-infinite solid whose surface is symmetrically heated on a circular spot. The thermal conductivity is assumed to be a linear function K = [a] + Bt; however, if necessary, any reasonable linear or non-linear function might just as well be used. The stability, convergence, node size,

Jan 1, 1971

By Teder R. I., M. M. Protodyakonov

In order to find an empirical relation between a quantity F and (m) independent variables or factors, each of which take (n) different values or levels, it is necessary to conduct nm different experiments (all possible combinations of the factors), each of which has to be repeated a few times (usually five) due to the scattering of the data. The total number of such experiments is very large, thus for example, when m = 4 and n = 5, it is equal to 5.54 = 3125; and very rarely is it possible to conduct such a number of experiments. Various possible methods of planning partial experiments are illustrated in Fig. 1. Each method shows a large combinative square consisting of five columns and five rows of middle squares, each of which, in turn, is further divided into five columns and five rows of cells. Such a partition corresponds to a plan of an experiment with four factors, each of which takes five different levels. The blackened cells indicate the combination of factors in a partial experiment. The total number of experiments is reduced on the basis of the following considerations: a) The effect of only a few levels of some factors is studied (Fig. la). Such an investigation gives no information on the effect of some factors, therefore it cannot be accepted as satisfactory; b) By reducing the number of levels of each factor; in such a case it is not possible to obtain an empirical relationship, but only whether some factors have an effect. This is evidently inadequate;

Jan 1, 1971

By Kenneth W. Luke

In the development of the ultimate pit limits for a narrow ore body, pa¬rameters necessary in the design of a functional, or working, pit become highly sensitive factors in the determination of ore reserve levels and their associated waste to ore stripping ratios. Through the use of geologic cross sections, ore reserves can be roughly calculated by utilizing a straight line approximation for pit wall slopes. The optimum position of the pit floor can be substantially altered from such a preliminary design though with the introduction of functional mining parameters, such as a ramping network, and working bench heights, berm widths, and bench to bench wall angles. Originally a computer program was developed to quickly evaluate changes in cross-section pit design with minimal alteration of input data. After developing a satisfactory technique of cross-section evaluation which incorporates working mine parameters, an optimization algorithm, or procedure, was developed and included in the program to eliminate much of the tedious manual decision-making required in determining the optimum location of the pit floor on each cross section. Optimization in this case implies the maximum profit pit. When pit and processing costs are defined or hypothesized, this computer program can be used to design the maximum profit pit, constrained by the recognized functional mining parameters. A second way of stating the optimization is that the program can be used to develop a pit design which minimizes waste stripping at any desired ore reserve level. The basic method of cross-section evaluation parallels present manual methods. Program input is a combination of data obtained directly from cross sections developed for, geological interpretation and pit design parameters selected by the mine planner. As a result it is easy for the mine planner to comprehend what the program is accomplishing, and thus participate in the development of the computer assisted design.

Jan 1, 1971

By W. H. W. Husband

Rock salt has been mined by the solution method for many years in many countries. Attempts have been made in the past in Canada and various other countries to produce potash by the' same method. However, only Kalium Chemicals Limited (1) has been successful, possibly because the conditions in Saskatchewan are the most favorable conditions to be found so far for the development of a solution mining method for potash. There are significant differences in solution mining of rock salt and solution mining of potash. First, rock salt deposits are relatively pure in respect to soluble minerals, whereas potash is never found in the pure state and contains Substantial amounts of other soluble minerals, particularly rock salt. In comparison to rock salt, much less potash is dissolved and brought to the surface for the same amount of water circulated through the orebody. The amount of water to be evaporated per unit weight of product is a major difference. Much greater amounts of water must be evaporated when producing potash and the treatment of the brine is more complicated because other dissolved salts have to be separated. Secondly, the rock salt deposits, particularly the domes, are much thicker. Bed thickness is of prime importance because it determines the yield of a well and consequently the economics of the process. Furthermore, as rock salt provides a strong roof structure, larger cavities can be developed and this prolongs the life of the rock salt well.

Jan 1, 1971

By G. C. Milligan

"A regional mapping program, conducted by the Nova Scotia Department of Mines, has shown that the George River Group of pre-Middle Cambrian rocks consists of a wide range of sedimentary and volcanic rocks, intruded by syenite, granite, granodiorite and lesser amounts of gabbro and diorite. Together, these rocks support the high ground of northern Cape Breton Island. Over this large area, the metamorphic grade ranges from low to extremely high.The rocks were folded prior to emplacement of the intrusions in Middle Cambrian time, and there was also post-Mississippian disturbance and faulting, but the structural history and pattern are still only imperfectly understood.Sulphide mineralization is known at Meat Cove, Lime Hill and in a number of smaller deposits. The most Cavour-able host rocks appear to be magnesian Iimestone, or schists derived from shales. Ail known sulphide bodies have an associated halo of retrograde metamorphism; in some cases, this is extensive enough to be used as a prospecting aidA vein of nickel-bearing sulphides has recently been re-discovered in the former gold mine at Second Gold Brook-an association which appears to be unique."

Jan 1, 1971

By B. D. Sparks, I. E. Puddington, F. W. Meadus

The continuous separation of bitumen from Athabasca tar sands, with a high clay content, has been demonstrated. Recoveries of 95 per cent or higher have been obtained. Further processing of this product, to produce an accept-able type of crude oil, would require less heat than currently used in the hot-water process. Also, by comparison, substantial savings in equipment and operating costs are indicated.

Jan 1, 1971

By Wayne L. Johnson

The depth capability of engineering seismographs has been greatly increased by the use of signal enhancement, a technique in which seismic waveforms created by repeated impacts are digitized, stored, and summed. Summation amplifies the signal and partially cancels background noise. This gives a clearer picture of the wave aid makes it possible to determine the travel tune of signals from 'eater depth. Signal enhancement combined with continuous display of waveform, permanent recording of waveform, and precision digital readout of travel time has opened new fields of application in mining and engineering. Recent work has clown that replacement sulfides can be distinguished seismically from country rock at Bistee, Ariz. Work on the Iron Range of Minnesota indication,: that, by using a 300 pound weight as the source, the Biwabik iron Formation can be traced down dip to several hundreds of feet traverses over known areas show that reflections can sometimes be identified. Reflection, if identified preclsely, give a mere accurate estimate of depth and buried topography. Comparison of ( ) and weight drop have given some understanding of low wave amplitude varies win; source candid

Jan 1, 1971

By J. R. Maxwell

The development, commercial installation, and operating performance of large capacity Maxwell Flotation Cells. Volumes ranging from 300 cubic feet to 2,000 cubic feet per flotation mechanism.

Jan 1, 1971