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By R. H. Colquhoun, A. W. Bolland, H. J. H. Pieterse

"American Barrick Resources Corporation acquired the goldstrike property in north eastern Nevada in early 1987. Since that time, the company has undertaken an extensive development program. This paper will overview the milling, autoclaving, and heap leaching facilities which are part of the $400-million Betze development plan. Gold production at the Mine has increased from 40,000 ounces per annum in 1987 to more than 500,000 ounces in 1991. And in 1992 Goldstrike will be the single largest North American gold mine when it produces 1,000,000 ounces.1. SUMMARYAmerican Barrick Resources Corporation acquired the Goldstrike property in northeastern Nevada in early 1987. Since that time, the company has undertaken an extensive development program. This paper will overview the milling, autoclaving, and heap leaching facilities which are part of the four year, $440- million Betze Development Plan. Gold production at the Goldstrike Mine has increased from 40,000 ounces per annum in 1987 to more than 500,000 ounces in 1991. In 1992, Goldstrike will be one of the largest North American gold mines, when it produces appro approximately 1,000,000 ounces.2. INTRODUCTIONAmerican Barrick Resources Corporation is in the process of developing the Betze gold deposit, located on Barrick's Goldstrike property in the Carlin area of Nevada, U.S.A.The Goldstrike Mine has 17.9 million ounces of proven and probable reserves and an additional 460,000 ounces of possible reserves. Additionally, the Purple Vein deposit, one mile north of the Mine, is expected to add at least 4 million ounces of reserves by year end 1991.The Goldstrike ore body contains both oxide and sulphide ore. The largest part of the reserves are contained in the high grade, deep sulphide ore. Mining of the sulphide ore contained in the Betze deposit involves the removal of large quantities of overlying oxide ore. Oxide ore is treated through one of the following processes:-"

Jan 1, 1992

By M. E. Holter

"Limestone-bearing strata are exposed in seven areas of Alberta, each situated adjacent to rail and road facilities. Six of these centers are located along the eastern edge of the Foothills and Front Ranges of the Rocky Mountains in western Alberta. The other is in northeastern Alberta, along the eastern margin of the Alberta Basin. High-grade limestones are present in Middle Cambrian, Upper Devonian and Mississippian strata. Middle Cambrian (Eldon Formation) limestones have been exploited only in the Exshaw area west of Calgary, where they formerly were used for lime production. Limestone beds of the Upper Devonian Palliser Formation are exploited at Exshaw and at Cadomin in west-central Alberta for the manufacture of cement. Reserves of high-grade limestone also are available in the Palliser Formation near Crowsnest Lake in southwestern Alberta and near BrUle, west of Edmonton. Upper Devonian limestones of the Waterways Formation are widespread in the Fort McMurray area of northeastern Alberta, but available data indicate they are of inferior quality to the limestone deposits of the Rocky Mountains regions. The Mississippian Livingstone Formation contains large reserves of high-grade limestone at several localities in the Rocky Mountains and Foothills. Commercial development of the unit is now underway at Crowsnest Lake and at Exshaw for lime production, and future exploitation of these beds is feasible at Blairmore and Nordegg."

Jan 1, 1973

By Gregory C. More O'Ferrall

Generally pillars in the Southern African hard rock tabular underground mining environment are designed using either empirical pillar design formulae or numerical modelling (analytical) methods utilizing the Hoek-Brown failure criterion. However, none of the pillar design methodologies employed takes cognizance of weak layers either within the pillar material or in the immediate foundation of the pillar. Over the past few years, the presence of a weak layer either within the pillar material or within the immediate foundation of the pillar has resulted in the closure of one platinum mine (Everest Mine), closure of one chrome mine (Wonderkop Chrome) and large-scale instability in a couple of chrome and platinum mines in South Africa and Zimbabwe. A study has been initiated to better understand the failure mode and strengths of the pillars where pillar failure associated with weak layers occurred. Owing to the infancy of the study into the failed pillar strength and failure mechanism, the purpose of this paper is to highlight the circumstances that led to the collapse of mining sections and a shaft, and the difficulty associated with designing pillars in the Southern African chrome and platinum mining operations.

Jun 1, 2012

By M. Romana

"RMR geomechanics classification is being used all over the World as a useful tool for tunnel predesign and construction. Bieniawski (1989) provided guidelines for tunnel excavation and support, according RMR numerical values; guidelines which are now included in almost all tunnelling books, regulations, and Internet portals. But in the last 25 years tunnelling techniques have changed and some of the guidelines have become obsolete.. The conditions of tunnels for the 1989 guidelines application were: horseshoe shape; 10 m width; vertical stress < 25MPa; construction by drilling and blasting. Actually a substantial number of tunnels are mechanically excavated. The tunnel themselves are now bigger: a span of 14 m. is very common for transportation tunnels. The guidelines included the following concepts: excavation method, rock bolts (20 mm diameter, fully grouted), shotcrete, steel sets. There is an increasing gap between the 1989 guidelines and the practice: in many tunnels different to-the-case excavation and support requirements are established. Bieniawski himself has published a paper (Lowson & Bieniawski, 2013) with different guidelines based in Lowson’s practice, with no explanations and/or justification.In this paper a new set of RMR tunnelling guidelines is proposed taking account of the actual industry conditions, and increased safety regulations. The 5 classes’ limit RMR:values (80,60,40,20) are no more useful actually: Values of RMR (70, 50, 30) are used in practice to define quite different tunnelling techniques. Consequently a 10 subclasses system is proposed. Each subclass covers a span of 10 RMR points. As the number of mechanically excavated tunnels has increased a new correction factor is necessary, according the excavation method.The proposed 2014 RMR guidelines are for tunnels 10 to 14 meters wide, the world practice for new roads/railways tunnels. Many tunnels for water/ services are smaller with smaller support needs. Wider than 16 m caverns are out of the RMR system.It is not possible, nor desirable, to propose only a value for support in each subclass. The new guidelines propose an interval of values for certain types of support. More pessimistic values must be chosen for wider tunnels, tunnels with lower RMR values in each class and cases when a higher safety factor is asked for. More optimist ones are chosen for narrower tunnels, and higher RMR values. Some alternatives are almost complementary, others are contradictory. Sometimes several different techniques are proposed Guidelines are not automatic options. Good engineering judgment must be used when choosing between the different alternatives. Guidelines are not mandatory suggestions."

Jan 1, 2015

By L. A. Wolff

"Second only to profitability (but not always), productivity is the most sought after measurement for any operation. Whether it is in mining, manufacturing, construction, etc. managers always strive to know how productive various plants are. Even the Federal Government publishes, on a monthly basis, the nation&apos;s factory productivity.Just what is productivity and how is it measured? This is an important topic that needs definition. There could be as many definitions as there are people who use it. In the mining industry, the problems of defining productivity would be analogous to the definition of equipment availability. Each mine uses its own definition to suit its needs. Webster&apos;s Dictionary primary definition for productivity is ""the quality or state of being productive,"" with productive defined as ""yielding or furnishing results"". This is a definition open to a broad spectrum of interpretation. A discussion of how productivity is currently used in the mining industry and an introduction to a potentially different approach to its measurement and meaning is outlined in this paper.Defining ProductivityTypically, mining companies track several productivity measurements. These are partial measurements and can include the following: tons per specific equipment class per hour, tons per man-hour, and tons per shift. None of these, however, track the over -all performance of an operation, that is, a unit of output per unit of input.For a mining operation, output can be defined as the ore for mill processing. Input includes the required components of production to get to the first step of processing.The Wesbter&apos;s Dictionary definition exposes a major fault with the popular conception of productivity. The critical issue of accountability is not addressed. Anyone can produce, but how effectively and efficiently are resources used? Quantifying an inclusive measurement is difficult. Statistics referring to an increase in productivity are often published. For example, the statement, ""gold productivity has increased by 10%"" has many potentially dangerous interpretations. One must ask, what does this statistic really mean? Did gold companies produce 10%” more gold? Were less manpower or equipment required to produce an equivalent amount of gold? Did ore grades increase resulting in more ounces of gold produced, etc. Obviously, production and productivity can have similar implied applications and meanings, but also two different, distinct meanings.To mitigate a problem like this, a standard needs to be developed within the mining industry. Because of varying ore grade, changing waste to ore ratios, different mining methods, etc. all of which have a direct impact on mining, development of a standard is difficult. Kendrick(1) discusses the use of Total Factor Productivity as a productivity measurement. Summarized, the total factor productivity measure is an indication of the change in efficiency in the use of basic labour and capital factors associated with an operation.This measurement has little meaning when calculated at a given point in time. It should be an on-going calculation, tracking an operation over a period of time, to evaluate trends. These trends can be used to determine if an operation&apos;s productivity is what it should be, and alert management to potential problems before they become major and adversely affect an operation."

Jan 1, 1990

By W. H. Mathews

"The Hardie group of cinnabar claims is in the interior of British Columbia; 25 miles northwest of the city of Kamloops. It is one of a number of mercury; properties scattered along a north trending belt 20 miles long and up to 5; miles wide. In all but one of these properties cinnabar is associated with; dolomite veinlets in zones of carbonate alteration in bedded rocks of Triassic; and Cretaceous (?) age; or in intrusives cutting these bedded rocks. No dolomite alteration or cinnabar mineralization is known in the undoubted Tertiary rocks adjacent to the mercury belt.The mercury showings of the Hardie group lie for the most part in a granitic stock cutting Cretaceous (?) volcanics. The rock in this intrusive shows marked variations in texture and has been described in earlier reports as granite and granodiorice, granite porphyry, and trachyte or dacite porphyry. At Hardie mountain the cinnabar mineralization, unlike that of the other properties, is associated with a fine-grained, almost chalcedoni c, quartz; carbonates, though present, are of minor importance. Some of the most interesting showings are found in an adit in the southeastern part of the property where cinnabar mineralization shows a very distinct structural but not a genetic relationship to a brown porphyry dyke 2 to 8 feet wide cutting a phase of the stock that may best be described as aplitic"

Jan 1, 1954

By A. Akerman, C. P. O’Connor, N. Vayenas

"Stereolithography is a well-known rapid prototyping technique in the manufacturing sector. Essentially, it is a three-dimensional printing process that produces plastic prototype parts from standard CAD files. At present, Canadian mining companies are not fully aware of the potential of rapid prototyping techniques (RPTs) for their production and mine design systems. Mining engineers and geologists attempt to visualize and understand the characteristics and layouts of orebodies on computer models, and in cases where it is decided to develop physical models, the process is time-consuming, based on simplified constructions. RPTs, such as stereolithography, can facilitate engineers and geologists to quickly, and with satisfactory accuracy, visualize sections of orebodies and evaluate alternative ore extraction techniques using 3D solid models.The research discussed in this paper is carried out by the Laurentian University Mining Automation Laboratory (LUMAL) in collaboration with Inco Limited and the Integrated Manufacturing Technologies Institute (IMTI) of the National Research Council of Canada. The main objective with this research is to evaluate the applicability of state-of-the-art RPTs to underground hard rock mining systems. RPTs can play a significant role in accelerating the design and development process of mining systems."

Jan 1, 2006

By A. J. Faulds, K. C. Westaway, Z. Waszczylo

"PAH compounds have been found in the exhaust from all types of engines burning hydrocarbon fuels . They have also been found in the air over cities and in water. The authors report on a study to assess the concentrations of twelve different PAH compounds in several different environments in dieselized underground mines. In addition, the differences in the PAH levels and distributions in different mines will be demonstrated. Finally, the influence of blasting and the type of diesel engine used as well as the effect of catalytic converters in the exhaust system on the PAH concentration in the mine will be discussed.IntroductionMining methods have been altered significantly in the last 25 years; i.e ., the tools and machinery used underground have changed from electrically operated trains and other equipment to diesel-powered equipment. This has been done for several reasons: 1) economics, 2) convenience and 3) safety. Today, most mines are heavily committed to using diesel equipment.Although the introduction of diesel equipment has revolutionized mining methods and has been a tremendous boon to the mining industry, it has also created new problems. These problems arise because the exhaust from diesel engines contains several pollutants which can be hazardous to the health of the miners. These pollutants are CO2, CO, NO., SO2, oxygenated hydrocarbons produced during the buring process and unburned hydrocarbons. There are two classes of hydrocarbons, of which polynuclear aromatic hydrocarbons (PAHs or PNAs) are a part."

Jan 1, 1981

By Sylvain Létourneau

Help organizations maximize the benefits of the data that they collect ? perform scientific research in: machine learning, data mining, statistics, artificial intelligence, soft computing, information retrieval, information systems, and natural language processing ? preferred application areas: Equipment Health Management, Bioinformatics, Health, Web Mining ? today?s talk limited to Equipment Health Management While the aircraft is still in the air, IDS: ? clusters relevant WRN, FLR, and snag (pilot) messages ? identifies probable causes based on TSM and provide links to corresponding TSM pages ? assesses MEL conditions (GO, NOGO, GOIF, ?) ? displays relevant maintenance history, suggests fixes based on similar cases ? Commercialization with MxI Technologies Ltd and Air Canada in 2000

May 1, 2008

By A. C. T. Bigg

"The mineral potential of the Nanisivik area was discovered as far back as 1910 when a prospector of the Geological Survey of Canada, on an expedition under Captain J. G.Bernier, recorded a deposit of pyrite with minor sphalerite and galena. An outcrop of the present orebody was discovered by Texas Gulf Company in 1957. Subsequent drilling outlined the orebody consisting of 6,000,000 tonnes of ore containing 13 % Zinc and 1.5 % Lead. The orebody appears to have been formed by the filling of a limestone cavern with sulphides. The sulphide minerals consist of pyrite, sphalerite and galena. The limestone bedrock is mostly dolomite with some calcite and magnesite. A cutoff grade of about 6% Zinc has been calculated.In 1972 Mineral Resources International Limited took an option on the property. Upon completion of the feasibility study by Watts, Griffiths and McOuat, the then new independent project management group of Strathcona Mineral Services Ltd. were engaged to develop the project through the financing, construction and operating phases. Strathcona Mineral Services still manage the project from their head office in Toronto and through the Mine Manager and Department Superintendents at the Mine site. The interest for the project is presently split five ways: Mineral Resources International Ltd. 53.5 %, Government of Canada 18 %, Metallgesellschaft A.G. of Germany 11.25 %, Billiton B. V. of Holland 11.25 % and Texas Gulf Co. 6 %."

Jan 1, 1980

By J. A. Finch, G. Labonté

"A long-standing objective has been to obtain interpretable measurements of the oxidation-reduction potential in mineral slurries. For this purpose several sensing electrodes (black platinum wire, platinum foil and spiral, gold foil and spiral, and sulphide minerals such as chalcopyrite and galena) were investigated to determine their response to the presence of sulphide minerals in the pulp, and to the addition of reagents commonly used in flotation. The observed discrepancies between the electrodes may be explained using a combination of the classical mixed potential model for complex solutions and the probability of contact between the mineral particles and the sensing electrode. It is shown from laboratory testwork that gold spirals are preferred over platinum electrodes. Finally, some of the practical aspects of using the electrochemical measurements in a plant environment are discussed.IntroductonThe interpretation of flotation of sulphide minerals in terms of electrochemical (electron transfer) processes has brought new possibilities for process control of selective flotation. Investigations on massive and compacted particulate bed electrodes have shown that the flotation of a given mineral in the presence of a collector can be controlled by the potential induced on the mineral surface. Also, phenomena such as collector less (self-induced) flotation, activation by heavy metal ions, and natural selectivity sustained by galvanic coupling during flotation might also be controlled by electrochemical means.The technique for measuring electrochemical potential in slurries is an adaptation of that used for solutions. The measurement of the oxidation-reduction potential of a solution (ORP , Redox, Eh) is usually carried out by immersing a noble metal electrode (platinum, gold or silver) and a non-polarizable reference electrode: Standard Hydrogen Electrode (SHE), Standard Calomel Electrode (SCE), or silver/silver chloride (Ag/AgCl) in the solution. (The abbreviation Eh implies the SHE is the reference electrode.) The potential difference between the two electrodes is measured using a high impedance electrometer. ASTM standard D 1498-76 (revised 1981)(1) covers the practical details of such measurements; however, it does not deal with their meaning either in complex solutions or in mineral slurries ."

Jan 1, 1988

By G. D. Bateson

"The Low NOx/SOx (LNS) Burner is a technology which, in pilot-scale tests, significantly reduces acid rain-forming emissions from the burning of coal. The precursors of acid rain are nitrous oxides (NO) and sulphur dioxide (SO:;) . TransAlta is currently planning two demonstration projects.Esso Resources Canada and TransAlta are undertaking a project to demonstrate how coal can be burned cleanly for steam raising in heavy oil operations by using TransAlta&apos;s LNS Burner on a steam generator at Esso&apos;s Cold Lake Production Project. The $10.7 million project started up in mid-J990, with testing to be completed in mid-I99J. The province of Alberta and Western Economic Diversification Canada, along with other private industry, are contributing funding to the project.The other demonstration project that has been selected for funding under the United States Department of Energy&apos;s Innovative Clean Coal Technology Program is a retrofit of LNS Burners to a 33 MW cyclone unit at Southern Illinois Power Cooperative&apos;s Marion generating plant. The US$13.6 million project is scheduled for completion 18 months after final funding arrangements are made.TransAlta believes that these demonstrations will lead to the development of a commercial ""clean coal"" technology. Other demonstration projects being planned will further broaden the base of applications.IntroductionTransAlta has recognized an increasing concern worldwide for the environment, and in particular the acid rain problem. Increasing public concern and the need to meet either current or possibly more stringent emission regulations have prompted them to explore various emission reducing technologies - despite the low sulphur content of its coal.The flue gas desulphurization (FOD) and selective catalytic reduction (SCR) technology currently available to reduce sulphur and nitrous oxides from coal burning power plants is very costly. Having to incorporate FGD technology, or ""scrubbers"", greatly adds to the cost of producing power. Having to add such high costs to electric customers&apos; bills is something TransAlta is striving to avoid.There are many research programs now underway which are evaluating ways to provide electricity from coal in a clean manner. TransAlta has been observing or participating in a variety of these programs. However, there is one new technology which the company has identified as having the potential to control acid rain causing emissions at a fraction of the cost of conventional systems. That technology is called Low NOx/SOx, Burner - or LNS Burner."

Jan 1, 1990

By E. Peters

Roasting processes are divided into several elementary mechanisms, any of which could be significant or pre-dominant in a particular roast. The elementary processes considered in-elude beat transfer, gas-solid inter-actions with accompanying mass transfer between the bed and furnace atmosphere, vapor phase transport processes in solid-solid interactions, and solid phase diffusion processes. Examples are chosen of processes in which one of these mechanisms pre-dominates and some recently obtained data is presented to support the existence and significance of these mechanisms. Proposals are also made for future research in these areas, and for utilizing the information in the improvement of roaster capacities’ OASTING of ores as a preparative treatment for smelting or leaching has been practiced for so long that its origin has been lost in antiquity, but little has been under-stood of its basic nature until fair-ly recent times. The nominal chemistry of roasting processes is now understood; that is, the initial chemical com-pounds present in the ores or con-

Jan 1, 1961

By Jean Cayouette

"In 1995, Louvicourt Mine started one of the first paste backfill operations in Canada. From 500,000 tonnes in 1995, the annual paste backfill tonnage produced reached 800,000 tonnes in 1999. The maximum throughput of the surface plant (including binders) is 3,50Ot/d with a final density of 75 to 76% solids which gives a slump of 15 to 17cm. Following the start-up of the paste backfill plant, the backfill strength performance levels were well below the pilot plant’s predictions. The introduction of ferrous slag, laboratory tests on various binder ratios with or without additives, and the desliming of the tailings enabled us to optimize the mix and operation costs. Primary and secondary stopes are filled respectively with a paste containing 4.5% and 2% binders consisting of a mixture of 20% cement and 80% ferrous slag. In certain stopes, the binder ratio may vary from 2 to 7%, but always in a ratio of 80/20. Six years after start-up, or 4.5mt of paste backfill later, this paper discusses the present operation and the major changes that have occurred over the years to optimize both the operation and the paste fill quality.INTRODUCTIONLouvicourt Mine is operated by Aur Resources Inc. which owns 30% of the shares. Its partners are Novicourt Inc. (45%, subsidiary of Noranda Inc.) and Teck Corporation (25%). The mine is located in the north-west part of Quebec, about 600 km north of Montreal and about 25 km east of Val d’Or. The mine commenced commercial production in July 1994."

Jan 1, 2002

By Brian G. Pewsey

Located in the northern part of the Province of British Columbia, the Cassiar Mine started development of its asbestos orebody in 1952, and is currently producing 105.000 tons of asbestos fibre annually. The townsite is nestled in a beautiful valley and supplies more than average facilities. The fibre is shipped to more than 40 countries and is used in many industrial products.

Jan 1, 1978

By Peter M. Watt

The objective s of this paper are: (a ) to examine and discuss the burdens we place on our extractive industry; (b) to compare the levels of taxation in Canada with those in other countries; and ( c) to suggest certain broad parameters within which our taxation policies may be made more rational and stable. Among the burdens identified are taxation, the ownership and use of our resources, environmental issues and the rather emotional issue of so-called &apos;super profits&apos;. Finally, the paper will address certain broad but key areas of policy which need attention and agreement if our tax system is to be made more rational. Such areas include: whether and if so why the extractive industry should be given incentives;. what circumstances, if any, justify a &apos;higher&apos; than normal&apos; level of taxation, and, ?if the concept of economic rents is a justifiable one, how might a basis for them be established which recognizes the fluctuating value of much of the industry&apos;s output. Note: The paper was written before the 1977 Federal and Provincial budgets were presented. Consequently, the paper does not reflect any changes proposed in these budgets.

Jan 1, 1977

By T. H. Etsell, P. Kerr, Qi Liu

"The objective of this investigation was to study the reaction mechanisms during the reduction of iron oxides in the presence of calcium chloride and carbon black as a simplified iron segregation process. The gas phase was analyzed by mass spectroscopy and the solid reaction products were analyzed by scanning electron microscopy. Mass spectroscopy, combined with thermogravimetric analysis and differential scanning calorimetry, revealed the presence of several gases at elevated temperatures over time, and the scanning electron microscope in combination with energy dispersive X-ray analysis illustrated the growth of a metallic iron phase on or near the carbon substrate. The results correlated well with similar copper and nickel segregation processes, but also introduced new insights that challenge the simplicity of the current models. The formation and transport of gaseous iron species to the carbon substrate in the presence of steam and hydrogen were evident during the reduction process that was studied; however, there is more happening at a mineralogical level, based on evidence of a liquid phase resulting in substantial growth due to an apparent fluxing effect created by the calcium chloride.These results help to better explain the chemical reactions and, in turn, the thermodynamics and kinetics of iron segregation processes related to the beneficiation of low grade complex iron ores. The results are also applicable to the production of metallic iron and concentrated titanium dioxide from ilmenite ores. The benefit of this process is that it allows ores in which the iron minerals are intimately associated with gangue minerals to be processed in circumstances where conventional mineral processing techniques are unsuitable or incapable of upgrading the material."

Jan 1, 2016

By S. Borle

The microstructural features produced in friction stir welded AZ31, AZ80 and AZ91 alloys are examined when different welding parameters are applied. The microstructures primarily consist of a-Mg grains with a-Mg + Mg17A112 colonies, however melted films of Mg17A112 are produced in AZ91 alloy when high rotation speeds are applied. When the rotation speeds are slow, or the travel speeds are fast the Mg17A112 were incorporated into the stir zone, however they do not exhibit an elongated lamellar morphology associated with melted films. In the case of AZ80, the extruded base material contains a smaller fraction of Mg17A112 and few of these phases are observed in the stir zones. The results are explained based on the dissolution rate and melting temperatures of Mg17A112 controlling the overall morophology and fraction of phases in the stir zone.

Jan 1, 2011

By H. B. Farnam

"THE IRON ORE Company of Canada has been using do-it-yourself type explosives for three years. During the last 12 months we have used over 10 million pounds of ammonium nitrate-fuel oil explosives and either purchased or formulated one million pounds of slurried explosives.W e have been moving approximately one million cubic yards of stripping and ore per month and we expect our production rate to in-crease. Eighty per cent of our strip-ping and ore is soft enough to be blasted successfully with ammonium nitrate-fuel oil mixtures. Twenty per cent of our material is extremely hard and requires an explosive having greater strength than an AN-fuel oil mixture.W e had been using canned am-monium nitrate base explosives and TNT pellets to give maximum bottom loading density to fracture hard rock. As AN -fuel oil became widely used, it was apparent that other types of explosives could be formulated to fit our blasting requirements. Dr. M. A. Cook of the University of Utah was consulted regarding new explosives and together we developed the blasting slurries.Figure 1 shows a general view of one of our hard rock pits. The foot wall is on the right-hand side and this material is called iron forma-Figure 1.-General view of hard rock pitstion by our Company but is called 'Taconite by the operators on the Mesabi Range. This material runs 35 to 45 per cent iron and many pieces are hard enough to scratch glass. The formation is tilted at an angle of 55 degrees as can be seen in Figure 3.The bedding planes of this rock are about 24 to 36 inches apart and if the material is not well broken or fragmented, large chunks or slabs must be handled by the shovels which reduces shovel capacity and efficiency and increases maintenance costs."

Jan 1, 1960

By P. Lausch, Z. X. He, J. F. Archibald

"Documented underground fill failures have resulted because of the lack of adequate knowledge concerning fill strength and other physical parameters, as well as to a lack of consistent quality of fill materials being used by operators. On the basis of literature review and correspondence with backfill operators at 18 mines throughout the province of Ontario, non-systematic quality control procedures have been shown to exist, both within different levels of single operations and between separate mining operations, which act to provide inferior engineered fill materials and erratic application response in situ.Assessment of existing procedures set by mine operators for determining backfill physical parameters, and recommendation of optimum fill material testing and manufacturing guidelines are presented in this paper.A series of standard fill characterization test procedures are recommended to provide substantial, though not comprehensive, fill behaviour review. The purpose of these recommendations is to propose industry standards for backfill quality review. Data acquired could be utilized for fill design functions and as a means of comparing fill quality parameters between sites in a regular and more systematic fashion than is presently done."

Jan 1, 1993