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By K. Waters, A. Navarra, T. Grammatikopoulos

Strategic decisions to develop a mineral deposit are subject to geological uncertainty, due to the sparsity of drill core samples. The selection of metallurgical equipment is especially critical, since it restricts the processing options that are available to different ore blocks, even as the nature of the deposit is still highly uncertain. Current approaches for long-term mine planning are successful at addressing geological uncertainty, but do not adequately represent alternate modes of operation for the mineral processing plant, nor do they provide sufficient guidance for developing processing options. Nonetheless, recent developments in stochastic optimization and computer data structures have resulted in a framework that can integrate operational modes into strategic mine planning algorithms. A logical next step is to incorporate geometallurgical models that relate mineralogical features to plant performance, as described in this paper.

Jan 1, 2017

By T. T. Chen

The iron- and elemental sulphur-rich residues generated during batch and continuous pressure oxidative leaching of Inco Limited's Voisey's Bay nickel sulphide concentrate at 150°C in sulphate-chloride media have been characterized by X-ray diffraction analysis and scanning electron microscopy. The residues produced during the continuous leaching of the pentlandite- and pyrrhotite-rich concentrate consisted predominantly of hematite and elemental sulphur, with minor amounts of goethite. Although the iron species generated in the batch leaching tests were similar to those formed during continuous leaching, the morphologies of the hematite and goethite particles were significantly different. In addition to the tiny spheroids and bubble-like particles, the hematite and goethite generated during batch leaching occurred as larger "hollow" shell-like particles that contained residual pentlandite or sulphur cores. Although the leach solution from which the iron oxides had precipitated contained 5-15 g/L sodium, sodium jarosite was detected only in trace amounts in a few of the leach residues.

Jan 1, 2006

By M. S. Badollet

Introduction The manufacture of some asbestos products involves the use of asbestos in combination with water, cement and granular fillers. This type of production is often called the wet or semi-wet process and requires the use of either pressure or vacuum to eliminate the excess water in the fibrous blend so that the product may develop the proper strength during the curing stage. Asbestos - cement products available today are numerous and are a valuable contribution to the building industry. Their production in quantity depends upon the type of equipment employed, the speed at which it can be operated, and the factors involving the? blending of asbestos, cement, water, and fillers. Assuming that all mechanical troubles at a plant have been eliminated or are under control it is still advisable to study the basic properties of the raw materials used in the asbestos-cement products. The type of cement used is an important factor, but usually the manufacturer of the cement is willing to work with the asbestos development engineer and recommend the proper type to be used for the product. The source of the water should not be overlooked as a general factor involved in the production cycle. Waters containing a high percentage of contamination such as silts, humus, or soluble salts may adversely affect the setting of the cement or cause a slowing down of the production rate in the factory. Asbestos in combination with cement is an ideal material fo1 building products. It is inorganic, will not deteriorate, and can be handled by mechanical equipment with a minimum reduction of fibre length. The many physical properties peculiar to asbestos fibres should be well understood by the manufacturer. They may be briefly enumerated as follows: fibre strength, fibre composition, sliminess, length, harshness, softness, and filterability or porosity. This last named property is important and it is the purpose of this paper to present some basic studies on filtration as applied to production problems.

Jan 1, 1949

By H. G. Wang

The production process of a coal mine can often be interrupted by all kinds of events scheduled or unscheduled and thus often needs gas drainage for a temporary or long-term sealed area. Gas drainage has a relatively high risk, therefore attention must be paid to its design to keep the process safe. Based on the conservation laws of mass and constituents, and under the conditions of the allowable gas concentration limit in the return air route, the relationship between gas concentration and gas drainage flow rate as a function of time during the drainage process is discussed in detail to build a mathematical model of gas drainage from a sealed area. With respect to the gas drainage process, two different conditions need to be considered: one with a methane free fresh air supply, the other with a low gas concentration. This paper presents the derived mathematical models for these situations and then shows that they can be incorporated into one model with some modification. This combined model can be employed to determine the optimum gas drainage flow rate with the shortest drainage time. The application is coded using the C# programming language within the .NET framework. Finally, the application program developed by the author is used to validate the mathematical model through an example of gas drainage with varying rate.

Aug 1, 2013

By F. Chiesa

The permanent mould process, which is a favoured process for producing premium quality aluminium casting, is rarely used to produce magnesium alloy parts. This may be attributed different factors such as: the reservation with which the automotive industry considers using magnesium in structural castings; also the relative hot shortness of most magnesium alloys when compared to aluminium A356/357 is another factor. A third reason stems from the fact that the "heat content" of magnesium is much less than that of aluminium, resulting in the difficulty, for a relatively slow process such as permanent mould (versus pressure die casting), to reach a mould dynamic equilibrium temperature sufficiently high to avoid premature freezing and misruns. The present work will address this problem by carrying out controlled cycling of a laboratory mould, poured with aluminium and magnesium alloys. The influence of insulation of the mould and artificial electric heating on the run-in mould temperature will be determined experimentally. A thermal model will be sought for these thermal devices that will allow to predict the thermal behaviour of moulds of different geometry before a single casting is poured. The model will be tested on an industrial casting in a workshop environment.

Jan 1, 2006

By F. Tanaka

Copper losses to discard slag have long impacted on the profitability of copper smelters. Businesses based on the treatment of secondary materials have also revealed that copper losses are indices of precious-metals losses. Many custom smelters are thus required to obtain more reliable controls for reducing copper losses than ever before. Mitsubishi Materials Corp. has cooperated with academic research institutes in conducting research projects on the pyrometallurgical fundamentals of copper smelting systems, including mutual evaluation of magnetite behavior between synthetic and industrial slags. The state-of-the-art pyrometallurgy has subsequently been introduced to Naoshima smelter for controlling the Mitsubishi process. The revised controls function successfully and the operational results demonstrate that avoiding the discharge of solid magnetite from the S-furnace is quite effective to reduce copper losses. Magnetite behavior has been controlled over the Mitsubishi process so as to reduce copper losses while satisfying the needs of recycling businesses growing in Japan. In-situ estimation of magnetite behavior using the absorbed heat from the melts to cooling water will also be discussed.

Jan 1, 2007

By K. Heid

"Although concentrated efforts have been made to deplete PCB transformers from the Canadian environment, numerous transformers (as well as ballasts, capacitors and magnets) continue to exist throughout the Canadian mining industry. The existing installed base is slowly being phased out as environmental issues come under increasingly high profile. The following article identifies the potential problems of owning PCB transformers and offers some solutions for their removal, disposal and replacement. IntroductionPolychlorinated Biphenyls (PCB) are synthetic chemical compounds consisting of chlorine, carbon and hydrogen. PCB was widely used in transformers due to its physical properties, including stability, low flammability and non-conductivity. Use of PCB in electrical equipment has been banned since 1977 when the extent of environmental contamination was discovered.Although PCB’s have been outlawed for use in electrical equipment since the late 1970s, safe storage regulations were not addressed until 1988 when a major spill prompted the federal government eventually to issue the storage of PCB Material Regulations in 1992. These regulations replaced the Interim order of 1988 under the Canadian Environmental Protection Act.PCB transformers are usually referred to as askarel filled transformers or as PCB contaminated mineral oil transformers. Askeral transformers were designed to contain high concentration PCB fluids, referred to as askarel. Mineral oil transformers were not designed to have PCB concentrations but were inadvertently contaminated during manufacture or maintenance activities."

Jan 1, 1998

By L. H. McKay

Tailing Dams Three types of dam have been structed to impound tailings from the Allenby mill: 1.- By classifier unit 2.- By earth dam 3.- By direct deposition of tailings The first type, which includes two dams, was built across a shallow valley which sloped down to Similkameen river, just below the mill site. Two earth embankments, one below the other, were built across the valley. Tailings were then piped to Akins classifiers mounted on wooden wheels. The classifiers were set up at one side of the valley and gradually moved ahead on the sand embankment created by the sand discharge from these classifiers, the slime overflow going to settli.ng ponds formed by the dams. Decanting wells were built in the settling ponds by placing four six-by-six timbers vertically in the ground, two feet apart, to which two-by-six tongue-and-groove boards were nailed. The elevations of the ponds were raised, as required, by nailing additional two-by-six boards on the well and bolting on more six-by-six timbers when required. The bottoms of the wells were attached to a covered launder made of three-inch lumber laid on a one per cent grade. This launder carried the overflow through the dam. The second type of dam was built across a long, narrow valley, known as Hitchen's Flat, the upper ~n d of which was about 2½ miles north of the mill. This valley, an ideal tailings site, was 4,000 feet long and from 600 to 800 feet wide. An earth embankment with a concrete spillway through the top was built approximately 28 feet high across the lower end of this valley. Tailings were then dumped into the upper end of valley, with no further expense until the basin was filled up to the level of the flume where this entered the valley. When the upper end of the valley was filled to this point there was still room for more tailings at the lower end. Therefore, a pump was installed to elevate the tailings to build a wall around the upper end of the valley by depositing sands from a launder built up on 20 foot supports and sloping both ways from the pumping station around the upper end of the basin.

Jan 1, 1950

By E. Onal

Mining operators are faced with complex information delivered by technology-centric rather than user-centric systems. The ability to achieve high situation awareness (SA) in the face of this data overload is a key challenge for effective decision making and information exploitation. Incidents that result in loss of revenue and even life, and compromise safety that are attributed to human error are often the result of system designs that overload human cognitive capabilities. This paper focuses on defining SA as it relates to mining operations and presents methods for improving SA through a scientific approach for electric shovel operator user interface development.

Aug 1, 2013

By G. E. Veins

This paper summarizes an investigation in which beneficiated ilmenite ore was smelted in a continuous, three-phase, 250 kv.a., open-top electric furnace. Minus %. inch ore was smelted, using the standard method. Fine ore, in the order of minus 14 mesh, was smelted in the briquetted form by the open bath method, and in the unagglomerated form by the cold dry-top method. The latter was shown to be superior. The data obtained .are discussed at some length. During the investigation, slag aver-aging 82.5 per cent Ti02 was produced over a period of 87 hours, the maximum being 85 per cent. Such slag should .be particularly attractive for the production of titanium tetrachloride, from which titaniurn metal is produced. The advantages of using paper-mill bark for producing a furnace charge of low bulk density, as required in cold dry-top smelting, were emphasized.

Jan 1, 1957

By John C. Lyons

"The Wabana iron ore deposits occur as flat-dipping beds of oolitic hematite and chamosite, of Lower Ordovician age, which outcrop for 3 miles along the northwest coast of Bell Island, Conception Bay, Newfound-land, about 16 miles from St. John's.The deposits occur in three zones, Upper, Middle, and Lower beds, separated respectively by 30 feet and 215 feet of shale and sandstone. They are primary sediments laid down in a shallow tidal basin by the precipitating action of a marine environment on iron-rich fresh waters flowing into the basin.The ore-bearing zones, while of wide areal extent, are not uniform beds of hematite that can be mined wholesale. The action of waves and currents during sedimentation; the delta pattern, velocity, and transporting power of streams flowing into the basin; the contours and oscillations of the sea bottom on which the sediments were laid have all been fundamental in the emplacement of richer and thicker mineable sections, and of lean zones so intercalated with shale as to be unmineable.The preservation of the deposits is due to their location in the Conception Bay syncline and to a considerable upthrust of the country east of the bay in post-Ordovician time.The hematite deposits were first recognized as such in 1892, and soon after were acquired by the Nova Scotia Steel and Coal Co. They are now being mined by Dominion Wabana Iron Ore, Limfred, a wholly owned subsidiary of the Dominion Steel and Coal Corporation, Limited. Production started in 1895, and up to the end of 1955 totaled 58,588,516 long tons of hematite ore, having an average dry analysis of about 51 5 per cent iron, 11 8 per cent silica, 0·9 per cent phosphorus, and l ·5 per cent moisture. About 40 per cent of the total tonnage mined has come from surface stripping and on-shore mines. These areas have now been almost completely depleted, and operations are confined to submarine mines extending for two miles off shore under the waters of Conception Bay. Three sub-marine slopes are currently in operation, Nos. 3 and 4 working in the Lower Bed and No. 6 in the Middle Bed. A general picture of the workings is shown in isometric projection in Figure 1. Submarine mining has been entirely by the room-and-pillar method, with an extraction of 60 per cent. The deepest workings, at a vertical depth of 1,850 feet below sea-level, have a rock cover of about 1,500 feet. No mining is done in areas where the rock cover is less than 200 feet. To date mining has explored six square miles of a potential area that may exceed 50 square miles."

Jan 1, 1949

By Karl J. C. Harries

"2.1. INTRODUCTIONNo agreement can be perfect in the sense that it contemplates and provides for all eventualities. Mineral acquisition agreements are usually negotiated and drafted at a time when an orebody is no more than a gleam in a geologist’s eye, so it is hardly possible to provide for development and operation in other than the most general terms. However, an agreement that stops short of contemplating the possibility of an orebody and production is ill-advised. Accordingly, it is important to provide procedures to make decisions that will let the project proceed, even in the face of a fallingout between parties. Whether the parties are shareholders in a corporation or venturers in a contractual common undertaking like a joint venture, differences of opinion and disputes will occur. Unfortunately, more and more are ending up before the courts. Besides greed and the growing tendency in society to fight rather than talk, there are other factors that contribute to the increase of litigation. In some jurisdictions, agreements have tended to become complicated, often defying interpretation, even by a lawyer, and explorationists want their budgets to go into the ground as constructive work rather than into a lawyer’s pocket. All this has led to a growing tendency for corporations to take the attitude that the chances of finding a mine are, at best, marginal and there are lots of earlier agreements in the files to draw from, so why not prepare their own agreements? As discussed in the preceding chapter, this can be folly. All these factors can quickly have parties facing each other in court while a project sits idle. Added to this is the problem that, in some jurisdictions, lawyers may take cases on a contingency-fee basis, sometimes promoting the pursuit of a nebulous claim.When an orebody is discovered, someone will always want some, or more, for himself. There is a breed of “prospectors” who prospect for legal actions, on the somewhat sound grounds that a major corporation will buy off nuisance litigation, rather than incurring the cost and effort of attacking even a poorly founded claim in the courts. They may even find a winner. Besides, it is far more comfortable and relaxing to prospect for problems and legal niceties than to prospect for an orebody.1 In short, it is appropriate to consider briefly some of the factors relating to lawsuits and judgments. Although many of the comments are made in the context of the common law and the Canadian legal system, most of the concepts and suggestions are applicable to any legal system."

Jan 1, 2003

High Pressure Grinding Rolls (HPGR) are said to be a good option in new grinding circuits. Due to their low energy consumption compared to other grinding systems such as SAG milling, there is a strong incentive to check their behaviour for certain ore types. With rising energy prices the operation will become even more beneficial in future. As published in the past, the HPGR is claimed to increase the liberation of the valuable mineral component within an ore. An investigation at the research centre of Polysius was conducted to substantiate the liberation behaviour in finish grinding operations. A pilot scale HPGR test unit (POLYCOM MAGRO) with a roll diameter of 950 mm and processing capacity of 80 t/h was used. Grinding tests were completed with a screen and a two stage drying air separation process (SEPOL). Analysis included standard screen analysis, fractional XRF and modern MLA technology. A technique was developed to oppose the amount of produced slimes (resuming bad flotation) against the positive effect of producing high mass fraction at flotation-easy sizes. The paper shows how effective the use of a dry grinding separation could be in terms of production of mass of liberated metal.

Jan 1, 2012

By Yan Yang

The Jinfeng gold mine is one of the three gold mines that Eldorado Gold has in China and it is the second largest gold mine in China. The mine is located in a relatively remote and mountainous area in the southwestern Guizhou province. The orebody is similar to the Carlin type deposit in Nevada. The mill throughput was designed to treat 3,600 tones per day. The ore comes from open pit mining and underground mining, and is fed to one-stage jaw crushing. The crushed ore is stockpiled, reclaimed and then fed to the SABC grinding circuit. After classification with hydrocylones, the ore is floated, and the resultant concentrate is oxidized biologically in a process known as BIOX®. The oxidized concentrate is then washed in a CCD circuit and finally leached with cyanide in a CIL circuit for gold extraction. Jinfeng produces about 180,000 oz of gold per year. This paper introduces operations and modifications of SABC circuit over the past three years, and then describes some technical characteristic of the SAG mill and other circuits in the processing plant. Major modifications and improvements on the SABC circuit are described in the paper, including: 1. Impacts of grinding ball and mill liner with respect to material selection, quality, hardness, manufacturing methods, and interactions between mill liner and grinding ball. 2. Effect of milling operation parameters on milling efficiency. 3. Impacts of SAG mill scats and modifications of grate size to improve mill throughput. 4. Design and construction of a pebble crushing system, and recycle the crushed scats to the SAG mill to improve mill throughput. With the above-mentioned modifications, 20% increase over the design in mill throughput has been realized over the past three years, and operating cost has been significantly reduced. However, some issues still remain, and thus process modifications and technical innovations are still needed.

Jan 1, 2012

By D. W. Ginsberg, D. Cieplinski

"The lifetime cost of a material handling system, or any mine system, can be reduced through the application of quality engineering. Dynamic simulation is a powerful tool that can be used to enhance the experience and ingenuity of the design team. It cannot only de-bottleneck the system to improve system productivity, but also define critical design criteria to eliminate over-design and reduce capital cost. Eliminating over-design also reduces operating costs by lowering component replacement costs and by ensuring all parts of the system operate at a higher utilization and efficiency. IntroductionA mine owner’s profitability is improved when a mine is developed at the lowest lifetime cost. This cost relates not only to capital and operating costs, but also, to a great extent, on the efficiency and reliability of the operation. These factors are tied directly to the quality of the engineering which depends on the experience of the engineers involved, and their ability to apply known system information in a rational and constructive manner.It is becoming apparent that it is increasingly more difficult to deliver the quality of engineering expected and needed to provide attractive lifetime costs using traditional design methods. Historically, system information has been evaluated based on a limited amount of information to which global rules-of-thumb and the engineer’s personal experience were applied to develop design criteria. However, market forces are dictating that more system parameters be defined and that they be defined more accurately so that the most economical system can be developed. This increase in the volume of information and the need for more accurate predictions is straining, if not already exceeding, the ability of engineers to apply simple global rules of- thumb and to combine all the information in a rational, comprehensive and representative set of design criteria. Furthermore, as proposed system production rates increase beyond established industry practice, the extrapolation of the engineer’s experience becomes more difficult and increases the risk in the proposed design."

Jan 1, 1998

By T. B. Williams

Most geologists have felt the need of a longer base than is ordinarily available when using a Brunton compass or other convenient instrument for taking strikes and dips in the field. To overcome this difficulty a lath or stick with straight parallel sides is frequently used. This accessory adds to the accuracy of the work, but it is a decidedly inconvenient one for the geologist to carry, especially if he be heavily loaded or is travelling on horse-back or through thick brush on foot. The writer has abandoned its use in favour of a sturdy two-foot carpenter's rule. The rule preferred is manufactured by J. Rabone and Sons, Birmingham, England. It is provided with a good level-bubble set in one of the limbs, and a scale, of the protractor type, graduated to five degrees through 180 degrees, attached to the main joint at the middle of the rule. (See Figure 1). For an instrument of its kind it is very accurate, and, in addition to the uses mentioned below, it 'is a handy thing to have around any camp. It is frequently used when plotting roughly in the field and for a protractor when one is not available. When not in use it may readily be carried in the top of the high-boot or legging. Ordinary strikes are measured as illustrated in Figure 1, the compass being held against the rule, which is in a horizontal position. Dips may be measured in a corresponding way by holding the Brunton compass against the extended rule, which is thus used merely as a straight edge. It is usually much more convenient, however, to ? use the rule only for this purpose, in which case one foot of the length rests as a straight-edge against the rock surface. This adaption is shown in Figure 2.

Jan 1, 1929

By P. O. Parfitt

At the McIntyre mine, there are two distinct operations: a gold mine with narrow veins, mined by cut-and-fill methods, and a copper mine with large, open, long-hole stopes. The application of the Critical Path Method to scheduling work in the copper mine, where it has been used successfully for several years, is de-scribed briefly. This application is relatively simple. Use of C.P.M. has now been extended to the gold mine. To replace the former method of scheduling from bar-charts, a procedure was developed for scheduling automatically. To handle an operation of this size and complexity, a computer was essential. Improved schedules are now being produced, with a saving in time.

Jan 1, 1967

By Tim Deans

This paper will address methods to manage hydraulic hose and coupling inventory so that parts will be available to build assemblies for the vast majority of equipment with as little inventory as possible. Topics also to be covered will include some basic hose assembly tagging techniques that will help keep equipment running by tracking problem hoses and building ?band aid? kits, having problem hoses premade in stock, and inventory usage tracking (one of the biggest problems for any inventory manager is knowing which couplings have been used so they can re-order). Cradle to grave tracking of hydraulic and industrial hoses insures reliable service of vehicles and ethical disposal of old hoses and couplings. With accountability for disposal of hose products that may contain chlorine (neoprene tube material in some hydraulic hoses) and carbon black that will be scrutinized more closely in the future, a proactive approach should be adopted in order to minimize maintenance facility problems.

Aug 1, 2013

By S. S. Yuan, Q. Z. Zhu, J. F. Shao

"This paper aims at enriching a homogenization-based anisotropic damage model for hard rocks under complex loading. A new damage criterion is proposed to capture material strain softening. Within the framework of irreversible thermodynamics, we are particularly concerned with two strongly coupled dissipative mechanisms: frictional sliding and damage by microcracking, which usually take place at cracks within cohesive geomaterials under compression. Focusing on the representative elementary volume containing multiple crack families, the free enthalpy of the matrix-cracks system is obtained. Importantly, a back-stress term is involved in the local stress applied to microcracks. This back stress plays the hardening/softening role in the friction criterion which is formulated at local scale. Strain hardening owns to the accumulation of frictional shearing and dilatancy while strain softening is caused by crack growth. The multiscale damage model is used to simulate laboratory tests on the Westerly granite under true triaxial compressions. INTRODUCTIONWhen subjected to compressive loads, hard rocks present nonlinear mechanical behaviors and induced material anisotropies. In that process, two main dissipative mechanisms have been largely identified: damage by crack growth and frictional sliding along closed crack faces, which are usually strongly coupled to each other on crack scale. Theoretical investigations have shown that the damagefriction coupling analyses allow explaining a large number of experimental phenomena involved in brittle or quasi-brittle materials. Concerning constitutive modeling, the standard Eshelby’s solution-based homogenization procedure for heterogeneous materials was recently applied successfully to describing the mechanical and poromechanical behaviors of cracked frictional solids."

Jan 1, 2015

By JAMES E. TILSLEY

Veins at St. Lawrence near the tip of the Burin Peninsula in southeast New/ oundland have been the major Canadian source of fluorspar. Some 2.8 million tonnes were shipped during the period 1933-1977, mostly from five of the more than forty veir.s known. Most of the veins occur in granite. individual veins may be several km in length, comprising a number of mineable lenses up to 760 m long and 25 111 thick. Fluorite content averages about 50 per cent, but may exceed 90 per cent locally. Quartz, calcite, barite and a few sulphides are the other vein constituents. Jn recent years, gravity concentrates were shipped to a flotation plant at Arvida, Quebec, where the fluorspar concentrate was used as a flux in the making of alum in um. Competition f rom Mexican fluorspar was a major factor in the closure of the mines. Ample reserves are available should economic conditions improve.

Jan 1, 1984