Search Documents

By R. D. Livingstone

"THE LETHBRIDGE COAL FIELD lies mainly .to the north and west of the city of Lethbridge. Mining carried on in this area for over eighty years until 1965. Before the building of a railway the coal was carried by bullock wagon to Montana for use in smelting, and for a while by river boat to Medicine Hat for railway use. The single, almost flat, worked seam is designated the ""Galt"" seam and is about 1.5 metres thick. It belongs to the Belly River formation and is under cover of 80 to 180 metres of weakly stratified sediments. A complex system of cross faults adds to the mining difficulties. Close timbering required in the entries and rooms reflected in a high timber cost and lower output per man shift. The coal is High Volatile"" C"" bituminous in rank with maximum gross calorific value of 11,200 Btu per pound and with a well defined cleavage. Roof conditions in the field range from very tender and very heavy on the south end of the field and west of the Oldman River to a more stable character to the north. Relatively speaking, the whole field would earn a rather tender rating and definitely so in relation to many U.S. fields. Floor conditions are characterized by a bentonitic type heaving in the south end of the field west of the Oldman river to a more stable situation in the north, which can tolerate shuttle car operation if kept drained. Water problems are minimal, except paralleling the Oldman River, where the seam dips below the river level. While vigilance is necessary to prevent accumulations of gas, the volume is rather limited. The seam was entered by shafts, except where small mines were located along the Oldman river banks and gained access by drifts. The coal seam was developed by driving either 3 or 4 Face entries 2 1/2 metres (8 ft) wide on 18-metre ( 60-ft) centres. Sets of dual butt entries driven at right angles to the Face entries completed development work. Normally rooms up to 8 metres wide were turned off the butt entries on up to 11 - metre centres. These were worked in groups of three to five, depending on the roof conditions, and normally advanced 60 m (200 ft). In some areas rooms had to be abandoned short of their objectives due to roof pressure, heaving floor and intermittent work."

Jan 1, 1985

By Edward I. Renouard

"THE mineral industry is constantly undergoing changes and facing challenges, and today we are in the midst of another serious one -namely, manpower requirement at every level in the mines, shops and plants. In the not too distant past we had a situation where labour was plentiful, although the equipment, by present-day standards, was quite inadequate, and that's easily understandable when you look back at the primitive methods by which our Western mines were first developed and operated, and then improved by the inventiveness and ingenuity of man.I'd like to show you a few slides from drawings made by Buck O'-Donnell which illustrate some of yesterday's methods of mining. Some of you probably had first-hand experience with some of these so you know they were tedious, time-consuming and involved a lot of heavy labour.Taking the Anaconda Company operations at Butte as an example, we can see what has happened in just the past ten years. In August of 1956, the Butte mines had 5,516 day's-pay employees and 976 salaried employees, for a total payroll of 6,492. In August of this year, there were 3,645 day's-pay employees and 605 on the salaried roll, for a total of 4,250. The number of contract miners had gone from 1,347 in 1956 to 606 in 1966 and that of other underground miners from 2,893 ten years ago to 1,149 this year. Along with these changes, however, another change of special significance has taken place, and that is in the number of skilled craftsmen, surface engineers and so on required for our operations. In 1966, we had 1,890 of these people, 600 more than in 1956 and nearly three times as many as just twenty years ago."

Jan 1, 1967

Abstract-This paper discusses the fundamental question, "what is an adequate sample size?" in the light of recent developments regarding parameters of Gy’s well-known formula for predicting sampling variance. New understanding of the granulometric factor, g, and the liberation factor, l, had significant impact on the results of calculations involving Gy’s equation. For the granulometric factor, justifications are given as to why nominal comminution size should always be reported as P95 (i.e., the screen size rejecting 95% of the mass). A small but important change in the model to estimate the liberation factor makes the difference between a predictive formula that works or does not. Other parameters and considerations regarding their practical implementation are commented upon in light of the author’s experience.

Jan 1, 1998

By Debasis Deb, Ankur Narang, G. P. Raja Sekhar, Kamal C. Das

"The stability of underground structures made (especially) in jointed rock mass is of the utmost important to designers, engineers and operators. Rock bolting is generally being practised to reinforce excavation walls and roofs by minimizing the movement of rock joints. This study proposes a new analytical model for the prediction of displacements, axial load and shear stress of a fully grouted rock bolt intersected by single or multiple rock joint(s). The governing equations for rock bolt are derived based on the assumption that shear force generated by slippage along the bolt-grout interface has a linear relationship with respect to the relative displacement at the interface. The proposed model is novel compared to the existing literature in the sense that it accounts for rock kinematics as an enriched sum of a continuous part (elastic) and a discontunous (jump) part due to the presence of joint planes. The complete solution of the bolt displacement, axial load and shear stress is derived as a function of the rock displacements, and, it comprises of Heaviside and/or Dirac delta functions in the solution space due to the jump at the intersection point(s) of bolt(s) and joint(s).Our novel solution is able to predict the elastic behavior of a grouted bolt, subjected to opening of the joint planes in pull-out test and also in excavated tunnel. These two cases also serve as benchmarks for grouted rock bolts with multiple joints and can be used for validation of numerical and experimental models. Further, the solution is applied to analyze the behaviour of grouted rock bolt as well as cable bolt installed in circular tunnel, with variations in rock joint(s) opening displacement, shear stiffness in the boltgrout interface and locations of the joint planes. Results indicate that for a specified grout stiffness, the maximum axial load developed in the bolt for discontinuous distribution of rock mass displacement is significantly higher than that of the continuous distribution of rock displacement. This paper provides an analytical interpretation of bolt beaviour considering multiple joint planes with variable joint opening displacements. The results obtained via the analytical method are in line with the corresponding investigation done by other authors. Thus, our analytical treatment can be used to understand bolt behaviour in realistic situations."

Jan 1, 2015

By G. Vibert Douglas

It often happens that the field geologist encounters a fault in ground where there is little to guide him with regard to the throw, or vertical displacement, and the heave, or horizontal displacement. The following construction gives both of these components of the fault, and the writers hope that it may prove a help to others. The construction is applicable to both normal and reversed faults. Briefly the procedure is as follows: Take a point which is common to the faulted geological feature and to the fault plane and on the downthrow side of the fault. Move this point in the horizontal plane in the direction indicated by the fault striæ. Rebat the point down to the plane of the fault and obtain its throw. Next consider the other side of the fault and truncate it down by the amount of the throw just determined. Then project the line of the geological feature through to the trace of the fault-plane at the lower horizon. The result is the relative positions of the two parts of the original geological feature as severed by the fault. In Figure r, let us consider a typical normal fault, that is, a fault in which the hanging-wall has gone down relative to the footwall. This characteristic, or its alternative, the reversed fault, is determined by observation on the ground. Let AB be the line of any geological feature such as the edge of a dyke, vein, or bedded sediment. The plane of which AB is the trace may have any dip; in the present case let us say 70° right. Let FF be the trace of a fault-plane which may have any dip; let us say 35° left in this case.

Jan 1, 1928

By G. A. McGuffin

"IntroductionWITH the increase in quantity of sour gas reserves in the Province of Alberta, and the wider market for sulphur brought about by mounting world demand and restrictions placed on the principal supply, it was inevitable that this important source of sulphur would be .developed. In the light of these facts, it seems timely that a general paper on sulphur recovery from petroleum gases be presented. This, then, is the purpose of the following text. A short discussion of each of the following subjects is presented:(1) Properties and uses of sulphur(2) Existing sources(3) Market research(4) The recovery process in Turner Valley(5) Hazards of sulphur productionNo pretext of originality of material is made since innumerable reports have been prepared on this and related topics and information contained in these has been used quite liberally.Properties and uses of SulphurSulphur is a non-metallic element having an atomic weight of 32.06. The stable crystalline form at atmospheric temperature is referred to as 'rhombic' sulphur. It is bright yellow and has a specific gravity of 2.05, equivalent to 129.2 lb./cu. Ft. Above 204°F. sulphur has another stable crystalline form, referred to as 'monoclinic'. This is reddish-brown and is slightly less dense than the rhombic variety (122.4 lb./cu. Ft.). Sulphur in bulk form weighs 84 to 90 lb. per cu. Ft. Sulphur melts at approximately 240°F. to a straw coloured liquid which is quite viscous."

Jan 1, 1952

By G. W. Poling, E. M. Coelho

"Sedimentary phosphate ores make up approximately 87% of the world's known reserves and are generally more difficult to beneficiate than igneous ores. In almost all cases, desliming prior to flotation represents the major source of losses. Laboratory studies of selective desliming of sedimentary ores are presented. Some fundamental studies with pure mineral systems are also discussed. Selective desliming, especially using selective flocculation, gave the best performance. Possible industrial applications of this selective flocculation-flotation procedure are discussed.IntroductionPhosphate ores are a major source of raw materials used in inorganic fertilizers (which supply nitrogen, phosphorus and potassium). Approximately 96% of the total world production of phosphate is utilized in the fertilizer industry. Reserves and production data are available in the literature. Today deposits with grades as low as 4% P2O5 are exploited in a few cases. However, in some northern African deposits, ore grades are still as high as 33 - 35% P2O5. Hout pointed out in 1982 that approximately 200 million tonnes of phosphate ore were upgraded by flotation only.Although there is a large number of phosphate minerals (over 300, only those in the apatite series are important ore minerals in phosphate ores. The most common member in this series is fluorapatite – Ca5(PO4)3F. However, in sedimentary phosphate rocks, many different substituents occur in the apatite lattice. Carbonate-fluorapatite (or francolite) is one of the most common names used to describe sedimentary apatites. It can be represented by the empirical formula:"

Jan 1, 1986

By D. Perednis

Fuel cells with thin samaria-doped ceria (SDC) electrolyte films deposited onto an anode support using spray pyrolysis were fabricated. The SDC films were deposited onto porous NiO-YSZ substrates at deposition temperatures between 400°C and 450°C. The influence of process parameters such as deposition temperature, flow rate, type of salt and salt concentration on the quality of the film was studied. A smooth dense film was successfully deposited using the precursor cerium ammonium nitrate and samarium nitrate dissolved in butyl carbitol (33.3 vol.%), 2-methoxy-l-propanol (33.3 vol.%), and ethanol (33.3 vol.%) solvent mixture. A deposition rate of 125 nm/h was achieved.

Jan 1, 2005

By Jaime V. Ongpin

"The author will give a capsule history of Benguet Corporation and attempt to identify its operating environment and underlying ""strategy"" until 1974, when the company's management assumed office. The company's operating environment and ""interim strategy"" from 1975 to 1980 will be described. The discussion will cover an environmental forecast and define the company's"" strategy for survival"" for the balance of this century.IntroductionIn December last year, I was asked to deliver a pa per for the management lecture series a t the Asian Institute of Management in Manila. The paper was entitled "" The 1970's: A Decade of Disaster For New Mining Projects"" . In that paper, it was my task to review the results of new mining projects in the Philippines during the previous decade. The task was not a happy one, for the results themselves were not only unhappy, but disastrous on a scale unprecedented in Philippine history. Out of a total of 17 major mining project s involving an aggregate capital investment in excess o f US $2 billion during the 1970s, only three project s have been profitable, and all the rest have either gone "" belly up"" or are teetering on the very edge of financial disaster.It is in the context of this shocking record of widespread financial dislocation in the Philippine mining industry, (which in varying degrees appears to have been paralleled in virtually every other country in the world where mining is an important sector of the economy) that I address myself tonight to the theme of this symposium. My paper is entitled ""Risk Management Strategy in Mining"" and it is sub titled ""Can Benguet Corporation Survive to Celebrate its Centennial in 2003?"". I have inserted the word ""Strategy"" and added the subtitle, because I wish to make it clear first, that my presentation to you tonight will be focused exclusively on the strategic aspect s of risk management, and second that I will limit myself to Benguet's own ""in-house"" experience and perspectives on this subject. I would caution you therefore, to consider my views within this restricted framework, and in light of the particular and sometimes peculiar circumstances within which Benguet Corporation operates."

Jan 1, 1983

By Cesar A. Urbano Jr., Gretchen T. Lapidus

A series of experiments examined silver extraction from a high-grade sulfide concentrate employing thiourea solution. Thiourea was initially oxidized with hydrogen peroxide (H2O2) to form formamidine disulfide (FADS) and used to extract silver from the as-received concentrate and after various pretreatments. Very low recoveries (~30%) were obtained with the as-received concentrate due to competitive cementation reactions by metallic iron and easily oxidizable copper phases. Over 80% Ag recovery was obtained when the concentrate was pretreated to remove this iron and copper. The results suggest that an oxidative acid pretreatment of this concentrates significantly improves silver recovery upon leaching with thiourea.

Jan 1, 2014

By Navid Bahrani

The grain-based model (GBM) has resolved the difficulty of matching both the directtension (sc) and unconfined-compressive (st strengths of typical brittle rock by providing a synthetic material that mimics deformable, breakable polygonal grains cemented along their adjoining sides with deformable, breakable interfaces modeled as smooth-joint contacts. In this paper, a GBM utilizing a parallel-bonded base material is calibrated to match both st and sc of Lac du Bonnet granite and then used to simulate a Brazilian test. The Brazilian strength (sB) is slightly overestimated and the failure mode includes ductile post-peak response that is not representative of what occurs in laboratory Brazilian tests. By reducing the grain tensile strength, grain failure occurs during the Brazilian test and a more realistic failure mode that includes brittle post-peak response is obtained. However, the unconfinedcompressive strength of the modified material is too low. Sensitivity analysis on the grain and grainboundary strength properties demonstrates that the grain tensile strength controls the sB/sc ratio. Because the grain strength is controlled by the parallel-bond properties and the lowest achievable st/sc ratio in a parallel-bonded material is ~0.25, it is concluded thatsc, st and sB for a typical brittle rock cannot be matched with a GBM that utilizes a parallel-bonded base material.

Jun 1, 2012

By Claude K. Howse

The area covered by the present paper consists of about fifty square miles in the immediate vicinity of the settlement of St. Lawrence, which is on the Southern extremity of the Burin peninsula on the south coast of Newfoundland. Physiography Physiographically, the area is part of the Atlantic upland, equivalent to the New England province of the United States. Evidences of two erosion surfaces are to be seen truncating the intrusives and the folded volcanics and sedimentary rocks. The older erosion surface is represented by small monadnocks from 650 to 750 feet in height with the younger surface covering most of the area and characterized by rounded subdued topography with maximum relief of two to three hundred feet and numerous ponds and bogs. These surfaces have been correlated with the High Valley and the Lawrence peneplains of Newfoundland. On the Avalon peninsula, these peneplains have elevations of, respectively, from 1,300 to 1,700 feet and from 500 to 1,000 feet. Glaciation The entire peninsula has been glaciated, with lee-and-stoss slopes showing on the highest hills in the immediate vicinity, many of which have striae and erratics on their summits. The lee-and-stoss slopes, the glacial striae, and the distribution of certain rocks found in the drift and whose source outcrops are known, indicate a southward direction of ice movement.

Jan 1, 1951

By P. Belley

Prior to 2006, the filtration unit for leached sludge treatment (filter press) permitted the filtration, washing and drying of cake to 17% (w/w) moisture. That year saw moisture content abruptly increase to 20% (w/w), drastically changing the rheological properties of the cake. The cake became sticky and agglomerated. This led to major disruptions of operations and plant capacity (cake release and cake conveyor problems, complicating the subsequent steps of the process). The conditions for the filtration, washing and drying, were simulated to ease cake unloading without aggravating dust emissions (moisture about 17% (w/w)). All of the laboratory tests yielded a moisture content above 17% (w/w). Therefore, we concluded that the moisture problems were not due to a recipe change in primary material, but to an operational problem in the filter press. Through the laboratory results, the filter press operating conditions (washing ratio, drying pressure and drying time) were optimized to enable a reduction in cake moisture to 17% (w/w).

Jan 1, 2007

By Mory Ghomshei

As fossil fuels become depleted over the next century, it is imperative that Canada and other countries examine ways to transition to other sources of energy, particularly renewable resources. A critical obstacle to developing Canada?s renewable energy resources is the scarcity of infrastructure to wheel the generated electricity to a viable market. For each megawatt of renewable electrical power, a maximum of 1 km of connecting power line is typically feasible. This means that hydropower, geothermal, and wind power projects with capacities up to 100 MW must be located within a maximum of 100 km of a main power line in order to be economically viable. With a total length of about 1200 km, the proposed Northern Gateway oil pipeline project creates an excellent opportunity to become a corridor that can seed renewable energy projects in Northern British Columbia and Alberta. Utility companies must build new infrastructure to provide the electricity for constructing and operating the proposed pipeline. The pipeline and linked power line infrastructure therefore, should be designed and built with consideration to create an energy highway to the significant renewable energy resources, such as hydro, wind, and geothermal, in the vicinity of the proposed pipeline. Some of the important renewable energy resources in northern British Columbia can be developed in connection with the proposed pipeline. It is estimated that close to 2,500 MW of commercially viable wind, geothermal and run-of-river power resources are present in the proximity of the proposed pipeline corridor. While oil flows westward from the Alberta bitumen fields, the generated green power can flow eastward to help the Canadian oil sand industry to offset as much as 10 Megatons of carbon emissions per year. The generated carbon credits are equivalent to 75% of the emissions associated with extraction of the 525,000 barrels per day of oil from oil sands, intended to be carried by the pipeline.

Aug 1, 2013

By S. Sillitoe

In mining, as in other business and engineering enterprises, efficient operation depends upon how well and how quickly the lines of communication can function. Mines have used the telephone on and between levels for many years, but in the hoisting shaft maintenance of physical wire connections for communication with the moving cage or skip has been found, for all practical purposes, impossible. A most natural solution was, therefore, the code-bell or buzzer signal system between fixed levels, and this has been standard practice throughout the mining world for many years. However, this system has serious limitations which make it impossible to signal a cage between levels in the shaft, and it requires crude, hazardous or costly methods for signalling during daily shaft inspection. Radio signalling overcomes these difficulties, because the communication medium is never broken and the cage-tender or shaft inspector can safely signal to, and receive signals from, the hoistman at any time from any position in the shaft, whether stationary or in motion. In addition to both audible and visual code signalling, two-way telephone communication and slack cable alarm are facilities made possible in recent commercially developed equipment.

Jan 1, 1949

By Dale Coffin

Definition Of A Crisis Crisis \kri-ses:\ An unstable or crucial time or state of affairs whose outcome will make a decisive difference for better or worse (Webster's New Collegiate dictionary) An event or set of circumstances that could significantly affect a company?s ability to carry out its business, damage a company?s reputation and/or threatens the health, safety and well-being of employees, the community or the public at large You?re Having A Crisis When... . The emergency poses a significant threat to the public or employees . The emergency situation provokes government scrutiny . The company no longer has full control of the situation . The situation has created significant regional, national or international media interest . The corporation?s reputation may be damaged or there is a threat to the bottom line or share value

May 1, 2004

By Floyd B. Bowen

Pumping methods are used, almost exclusively, to transport materials in the mining, beneficiation and chemical processing of phosphate rock in the Florida phosphate pebble field. Matrix pumping systems capable of pumping 15,000 g.p.m., transporting 15,000 long tons (dry) per hour, are now in use. They utilize 16-by 48 Yz -in. pumps, driven by 1.250-h.p. motors, discharging into pipelines 20 inches .in diameter .and sometimes several miles in length. As an average, it is necessary to pump 3 tons of matrix to the beneficiation plants, and to dispose of 2 tons of sand tailings and clay as waste, in order to produce 1 ton of shipping-grade rock. The washers and flotation plants, where the clay and phosphate and silica particles are separated, require the movement of large volumes of slurries with densities ranging from 2-3 per cent to 45 per cent solids, by weight. Extensive waste disposal systems require the pumping of dilute clay slurries in quantities of up to 50,000 g.p.m.,

Jan 1, 1963

By J. Lui

Inco Copper Cliff Smelter commissioned two new Inco flash furnaces in 1991/1993 as part of its S02 abatement program. Each flash furnace is equipped with a fluid bed dryer. The ~ 12 wt% water content in the concentrate filter cake, flux, reverts and sludge is removed in the fluid bed dryer. The dry solids are discharged from the dryer together with exhaust gases into the baghouses where they are separated. The dry solids are transferred to four storage bins. In September 2003, for the first time since startup in 1991/1993, a large amount of elemental sulfur accumulation was discovered on the walls, roofs and floors of the outlet side of the baghouse chambers. Several baghouse fires were experienced during cleaning and conducting maintenance work in the elemental sulfur contaminated baghouses. Laboratory scale test work at the Inco research lab was conducted to understand the mechanism. A plant solution to minimize elemental sulfur formation was implemented with success. This paper summarizes the efforts to understand and minimize elemental sulfur formation in the baghouse chambers.

Jan 1, 2007

By W. Geslin

Backward extrusion process is a metal forming process, which limits the manufacturing?s extra thickness when compared with classical die forging technique. Because of a lack of alloy?s mechanical behavior knowledge, the basic strategy of design is as follow: ?Definition of a small scale blank ?Performing experiment in order to get useful process data ?Improvement finite element simulation conditions ?Development of the full scale blank forming process (design of tools,...) using the finite element simulation A comparison between the result of modeling and the experimental data has been done to validate the finite element simulation.

Aug 1, 2010

By H. Helmstaedt, P. Thurston, R. Harrap

"Evolution of the continental lithosphere over Earth’s 4.6 billion year history is one of the fundamental questions of geoscience. Much of the Earth’s present-day continental crust formed during the first 2 billion years, the Archean eon, of the planet’s lifetime and thus, Archean processes of lithospheric formation must be studied in order to address this question. Until recently, the processes of Archean lithospheric evolution were thought to be fundamentally different from present-day plate tectonic processes. However, subsequent evidence suggests that the growth of Archean continents may be explained in terms of modern tectonic accretionary tectonics similar to those presently operating in the southwest Pacific region. The evidence supporting this hypothesis was compiled largely by Canadian geoscientists working in the Superior Province of the Canadian Shield in northwestern Ontario, over the past 15 years. Study of Archean rocks is also economically important because the Archean rocks of the world, although comprising only a relatively small fraction of the exposed continental crust, contain much of the world’s mineral wealth, including more than half of the world’s gold, as well as significant base metal reserves. Furthermore, the vast majority of primary economic diamond deposits are derived from the lithospheric roots beneath Archean cratons.The LITHOPROBE Western Superior Transect is located within the western part of the Superior Province in northwestern Ontario (Fig. 1). The Superior Province is the largest and best exposed Archean crustal block in the world and forms the nucleus of the North American continent. The internal structure of the Superior Province records a history of the processes that formed the earliest lithospheric elements of the Earth into cratons, thus providing an ideal laboratory for investigating early crustal evolution. The Western Superior Province is characterized by a regional pattern of alternating, 100 km to 200 km wide geological belts (Fig. 2). The observed geologic relationships between and within these subprovinces have been explained in terms of a modern tectonic model of terrane accretion. Oceanic floor, volcanic island arcs, oceanic sediments and continental fragments were accreted successively from north to south against the southern margin of a cratonic nucleus (North Caribou terrane, Fig. 2) which grew steadily in size with the arrival of new terranes through geologic time. If this model is correct, it suggests that the tectonic processes operating today have been active without major variation over the past 3 billion years."

Jan 1, 1998