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Jan 1, 2002

By J. E. Williamson

Introduction 1. Factors on Which the Design of the Roaster Plant was Based The roasting operation at Lake Shore, it was realized from the outset, would be profitable only if costs and losses could be reduced to a low figure. It was absolutely imperative that the operation should be self roasting over the whole range of tonnages and sulphur grades which might obtain during the life of the mine. The roasting operation could not bear the cost in fuel and labour of even a partially fired roast. To meet this requirement, it was necessary to resort to additional insulation in the construction of the roaster and to provide a more flexible means of rabble cooling than the conventional water jacket (see p. 31). A second basic consideration was that of handling a wet, putty-like concentrate. The operating costs of a drier ruled out the possibility of drying the charge before feeding it to the roaster. Moreover, the dusting which would result from charging a dry product virtually all -40 micron (325 mesh) in size would seriously handicap the use of a dryer. Dust lubrication (p. 3S) due to the back-mixing action of the Edwards rabbles, and the use of a Sullivan slapper ( p. 27) on the concentrate filter, completely solved the problem of handling the roast feed. The third consideration was the reduction of dusting to a sufficiently low point that a Cottrell or other dust collecting system was unnecessary. The Edwards roaster when properly supervised, it is believed, can be operated to give the minimum possible dusting. At Lake Shore, the evidence has been that less than 1 per cent dusting occurs at any time and that the greater part of the dust produced is recovered either in the spray tower or in the dust chambers.

Jan 1, 1947

By C. M. Diaz, S. W. Marcuson

In the late 19th century, the discovery of rich nickel-copper sulfide ore bodies in Sudbury and the need for tonnage quantities of the metal to be used in nickel steel armor provided the foundation for establishing the Canadian nickel industry. For almost 50 years, International Nickel was the key player. In 1930, Falconbridge Nickel entered the field. These two companies remain the key Canadian nickel producers. This paper discusses the factors that have influenced the evolution of nickel smelting processes. The initial Sudbury ore smelting and nickel copper separation technologies were imported from abroad. It was only in 1937 that International Nickel established a process research laboratory in Copper Cliff The explosive post WW II industrial development created a strong demand for a broader variety of nickel products. For both International Nickel and Falconbridge, R&D became an essential business tool to succeed in the new market scenery. In the last few decades, new technologies were developed and commercialized to respond to the raising cost of energy, society pressing environmental concerns, the advent of nickel laterites as an important source of new metal, the incorporation of new nickel producers to the market, and, therefore, the need to increase productivity. Canada thus became an important exporter of technology. In this paper, the authors review this history with the objective of highlighting the forces that have triggered the most important changes in Canadian nickel smelting.

Jan 1, 2005

By Robert L. Kranz

Mining-induced microseismicity data collected by the U.S. Bureau of Mines in a hard-rock mine were analyzed for spatial and temporal patterns that might prove useful for prediction of rock bursts or assessment of rock mass damage changes. Pattern attributes described and illustrated in the previous report (part 1) were applied to the study of aftershock sequences associated with two different stopes. The aftershock sequences were spatially and temporally fractal, and the fractality was maintained for up to 16 h following a sequence progenitor. This suggests mechanical interdependency among the after-shocks. No statistical difference was found in the distributions of fractal dimensions when comparing two different stopes or when comparing aftershock sequences initiated by blasts or bumps. This suggests a lack of sensitivity to both stress perturbation mechanism and local damage states. However, differences between the two stopes were found in other sequence attributes that support inferred differences in the magnitude of stress concentrations and damage near each stope, and over time as a stope is developed.

Jan 1, 2010

By W. G. Pariseau

A two-dimensional finite element program has been modified and extended to account for some of the rock mechanics complexities associated with single entry development of longwall coal mine panels. Program capability includes arbitrary assignment of element properties without regard to element ordering, anisotropic elastic, plastic and brittle rock properties that may be time dependent (aging), arbitrary mining sequences and provision for the effects of artificial support on the adjacent strata. Failure is according to an extended von Mises criterion that may be linear or quadratic in form; flow rules are obtained from the yield function taken as the plastic potential, but brittle behavior is treated as a discontinuous process of material properties change with deformation. In either case the extent of failure is calculated from the external boundary conditions. Application of the program to essentially two-dimensional problems resulted in lose agreement between calculated displacements and field measurements in the double entry system. Bleeder entries were stable in one locality and not in another. Artificial support had little influence on stability.

Jan 1, 1978

By G. H. Bennett

A field experiment was performed in a production unit of an operating copper room and pillar mine to compare the support capabilities provided by resin and mechanical roof bolts. Resin and mechanical roof bolts were alternately installed in eight intersections in a single entry. Rock mechanics instrumentation was installed to measure roof sag, bed separation, convergence, bolt pullout, torque, and strain. Bolt cost and installation time are included. Two analyses of the test were made. The analysis of the rock mechanics data showed there was no definite difference between the two bolting systems. From a broader analysis on a mine-wide basis it was concluded that resin bolts gave better support. A critical view of the experiment is given in the appendix.

Jan 1, 1974

By Ivor Hawkes

The purpose of the development described in this report and as stated in the contract work statement is to "design, develop, fabricate, test and demonstrate, and deliver to the government permissible low cost cylindrical stress gauges and associated components capable of measuring change of stress as a function of time in underground coal mines. The cylindrical stress gauges shall be suitable for installation in bore holes". The technique adopted for measuring rock stress changes is to preload a steel cylinder diametrically across the sides of a 1-1/2 in diameter bore hole and detect deformation of the cylinder from stress changes in the rock, by means of a vibrating wire transducer. By calibration, changes in the period (time for one wire oscillation at the natural frequency) of a high tensioned wire stretched diametrically across the cylinder in the direction of load application are related to stress changes in the rock. To completely evaluate the stress field change in the plane of the bore hole, three gauges set at an angle to each other are required.

Jan 1, 1973

By D. Randolph Berry

Foster-Miller Associates has developed a set of guidelines to permit hoist manufacturers, mine owners, and MESA mine inspectors to design, purchase, install or inspect a safe and effective Emergency Escape Hoist, as required by the Coal Mine Health and Safety act of 1969. A series of surveys were carried out to determine: 1. The attitudes and local needs of the MESA District Managers. 2. Current escape hoist installations. 3. Equipment available for future designs. 4. Foreign methods and equipment for mine rescue. From these survey studies, preliminary guideline objectives were developed.

Jan 1, 2012

By G. B. Shea, R. A. Cattell

This resume of the work of the Petroleum and Natural - Gas Division of the Bureau of Mines for the fiscal years 1940 and 1941 is the second of a series. of progress reports . It brings forward from the 1939 annual report information on the course of activities of the division in carrying out its objectives of increased conservation and better utilization of petroleum, natural gas, and related resources through a coordinated program of research and fact - finding . It discusses, also, special assignments. executed for other Government agencies, which in recent years have constituted a considerable part of the division's work ." . In the present national emergency, in which petroleum is so essential , many of the Bureau's research activities bear directly on the availability, conservation, and use of petroleum for national defense . Accordingly, during the past year attention has been focused for the most part.on.problems associated with the needs of national defense . Several long-time researches , which in themselves are potential sources of desirable knowledge , were judged to be of secondary importance under present conditions and accordingly were suspended . Studies also were oriented in line with rapidly changing conditions to meet the demand for accurate findings on short notice . The Petroleum and Natural - Gas Division has experiment stations at Bartlesville , Okla . , and Laramie, Wyo . , a field office at Dallas , Tex . , and a field office and laboratory at San Francisco , Calif . It also operates the Government helium plant near Amarillo , Tex. In addition to the helium operations , some of the petroleum and natural - gas research activities are conducted at the Amarillo plant .

Feb 1, 1942

By A. Henchiri, G. A. Gruber

INTRODUCTION Phosphatic resources may be quantified in terms of ore tons and phosphate analyses; however, to quantify phosphate reserves it is necessary to estimate the tons and quality of phosphate rock that can be extracted from the ore. The yield and grade of phosphate rock that can recovered from sedimentary phosphate deposits are usually difficult to estimate because of variations in stratigraphy and/or mineralogy. Prospecting phosphorite ores for purposes of estimating reserves and preparing mine plans requires considerably more effort than defining ore thickness and P205 content. In Florida, for example, it is standard practice to prospect by core drilling and to subject each strata (split) to beneficiation testing, and to perform detailed chemical analyses on the beneficiated products from each strata. For a completed drilling pattern the area of influence of each hole is 2.5 acres. The number of strata per drill hole typically varies from two to five, and thus complete prospecting of a 40acre tract requires drilling 16 core holes and beneficiation testing of about 48 ore samples. Florida practice is not appropriate for all phosphorite deposits. Functional drill rigs and trained drillers may not be readily available. Water for core drilling may be unavailable and the characteristics of either the overburden or ore may require careful attention and excessive cost to obtain representative core samples. Alternate ore sampling methods include auger drilling, rotary drilling to obtain cuttings, and the excavation of trenches, pits, and shafts. Drill cuttings samples are generally the least expensive to obtain, but they are usually unsuitable for beneficiation testing because of particle size reduction during drilling. Ore samples from surface trenches and pits are expensive and may not be representative of deeper ore. Ore samples from shafts are the most expensive to obtain, but if taken properly they are reliable for use in laboratory and pilot plant testing. Regardless of the prospecting technique used, reliable estimates of the yield and grade of phosphate rock that can be extracted from an ore deposit are required: • to justify capital expenditures for a new mine • for mine design and mine planning • for beneficiation plant design • for production forecasts, quality control, and marketing. This paper describes models that predict the beneficiation response of ores from three phosphate ore deposits. The purpose of these models is to obtain maximum utilization of available prospect data with the least cost. ORE DEPOSITS Simple beneficiation models have been developed for ores from three sedimentary phosphate deposits around the Mediterranean area. The first deposit, herein described as "A" ore, is located north of the Mediterranean Sea. The second deposit, designated as "B" ore, is located east of the Mediterranean Sea, while the third deposit, "C" ore, is located south of the Mediterranean Sea. Ore "C" is from the Sra Ouertane deposit in northwestern Tunisia.

Jan 1, 1993

By T. Egleston

circumstances, would prefer the steel with which they are now familiar, to a specimen that Mr. Sandberg has described as having broken into seventeen pieces under the wheels. After blowing such low manganese steel, it may be coaxed into a rail, but it is a wonder that it holds together so long as it does, with so great a nornber of minute flaws. I would not in any way depreciate chemistry, but I think it should be kept in its proper sphere. Let the chemist look after the quality of pig metal, and apply common sense in the avoiding of extremes, then the most fastidious railroad cannot find fault with the result. PROFESSOR EGLESTON, New YORK City : It is not my place as an engineer to apologize for the chemists, but as no one seems disposed to do so, and as they have had more than their share of criticism, 1 am glad to say that I believe there are chemists in this Institute whose work and word are just as reliable, arid perhaps even more so, than that of the average engineer. But we ought to make a distinction; there are chemists and chemists. With the ordinary commercial chemist, who looks upon the science as so much merohandise, I have not a particle of sympathy; but with the chemist who looks upon his profession as engineers do upon theirs, I have every sympathy. When matiufactorers and engineers go to a chemist and ask him to make an investigation, and scretv him dowu to the lowest point, turning the equivalent of his brains into cents and mills, they ustially get an exact equivalent in poor work for miserable pay, and no one has or should have any sympathy with them, and the under these conditions has no right to ask for any, and no reason to criticise any work that he may get under such circumstances. But I am disposed to think that the chemists who have been replwented and discussed at this meeting do their work conscientiously, and that it is as reliable as that of almost any profession. I believe, however, that this problem of steel rails is being investigated in a wrong direction. I said so at the Pittsburgh meeting, and I think the discussion of this meeting will prove it to all those who have heard it. I think the chemigt is incapable of solving this problem unlees he goes very far into the domain of physical chemistry, so far that it becomes physics and not chemistry; and that the physicist will be the one on whom we must rely in the future for the elucidation of the subject. The chemist may aid the physicist, but it is my decided opinion that we are looking in the wrong place to get the explanation of the phenomena.

Jan 1, 1881

By John E. Miller

Unit Rig & Equipment Co., manufacturer of Lectra Haul trucks, is continually studying methods of reducing the operating costs of large haulage trucks. Reduction of haulage system operating costs is an important goal that equipment operators and equipment manufacturers constantly try to improve on. One of the most variable and important factors affecting operating costs is actual truck operating practices. An examination was centered on methods to optimize truck utilization. It was found that a very effective method of accomplishing this goal would be an automatic truck control (ATC) system to automatically control a fleet of haulage trucks in a predetermined pattern. Economic studies were conducted which showed a very favorable reduction in mine operating costs by use of an ATC system. In 1970, Unit Rig & Equipment Co., in conjunction with SAAB-SCANIA began preliminary development of adapting, for truck use, a proven automated control system, previously used for train systems, small trucks, and military target vehicles. In 1974, the first prototype system was installed on a Lectra Haul M-100 and tested extensively at Unit Rig's test track in Tulsa, OK. This truck and system were then displayed publicly at the 1974 convention in Las Vegas. In 1976, the system was redesigned for production to maximize reliability, ease maintenance, and to accommodate future control and-status reporting developments proposed for haulage trucks. The new design equipment was manufactured, and a full system test will be conducted in an actual open-pit mine for an extended period to evaluate reliability, compile economic data, and obtain application information to evaluate complete mine haulage system conversions to ATC. System Description The ATC system is designed to provide automatic control of all the vehicle functions normally accomplished by the vehicle operator. The basic system consists of the on-board control equipment and the wayside control equipment. The on-board equipment receives commands from the wayside equipment and controls all the truck functions. In addition, on-board sensors monitor all critical truck functions and provide instructions to the truck and system to assure safe operation. The wayside equipment consists of a buried guidewire, block control units and a central controller which provides predetermined signals to the on-board equipment for speed control, steering, and for auxiliary functions (dumping, horn, etc.) through the guidewire located in the truck's path. The wayside equipment also controls vehicle separation, system status, and provides truck location to a central display panel. The central control panel can vary the speed level signals over any segment and can also command an emergency stop to halt all the units. [Fig. 1] illustrates a typical ATC installation. If ATC is used in operations which require flexibility and mobility at the end of the ATC guidance network, the trucks can then be operated by either radio remote control or manually to complete their assigned functions.

Jan 1, 1982

Slope stability is a critical safety and production issue for open cut mines. The æslope stability radarÆ has been developed to remotely scan a rock slope to continuously measure the movement of the face. The system can detect and alert movements of a rough wall with sub-millimetre precision, and with reliability and resolution. The advantage of the slope stability radar over other monitoring techniques is that it provides full area coverage without the need for mounted reflectors or equipment on the wall. In addition, the radar waves adequately penetrate through rain, dust and smoke to give reliable measurements, 24 hours a day. The measurement technique is tolerant of vibrations and overcomes the need for a highly stable footing required by traditional surveying systems, making it easy to move from one location to another. The system is self-powered and designed for minimal maintenance. Radar displacement images, co-registered with digital photography images, are transferred from the radar site in the pit to the mine office via a radio telemetry link. Custom-written software provides mine managers and geotechnical engineers with a complete picture of slope movements over defined time intervals. The time-history of the movement of any selected points or regions on the slope can also be displayed. Also provided is the ability to set movement thresholds that will trigger alarms at the radar site or mine office. The system has been used at numerous coal and metalliferous mines in Australia, and has provided real-time monitoring of slope stability during active mining operations. More than 20 rock wall and spoil failures have been captured by the system, and on every occasion adequate warning was provided to mine operators. The high level of movement precision and broad area coverage of the rock face provides a better understanding of the geodynamics, which leads to extra warning time. This technology enables a radical change in the management of risks in open cut mining operations.

Jan 1, 2003

By G. R. Fitterer

NonmEtallic inclusions in steel have received much attention by metallurgists during the past few years. Many investigators have been emphatic in stating their belief that these impurities are the chief causes of steel failures, while others think that their effects are negligible. One of the main reasons that definite information on the effects of these impurities is lacking is that no reliable method has been developed for the exact determination of the amounts of these different impurities in steel. Some valuable new information has been brought out by a reliable method for nonmetallic inclusions which has been developed at the Pittsburgh Experiment Station of the U. S. Bureau of Mines, in cooperation with the Carnegie Institute of Technology and the Metallurgical Advisory Board. This procedure satisfactorily extracts some of the more common inclusions from steels, thus enabling the investigator to correlate steel failures with inclusion content. Although the data given herein are the first to be published on the subject of the electrolytic extraction method, the interest in the subject is evidenced by the fact that it is already being used by some 20 to 30 steel companies for their various purposes. Some of the comments received from these laboratories indicate that the method is highly satisfactory: the unfavorable comments, when traced to their sources, have been found to be based on some small mistake made in either installation or operation. The chief discrepancy seems to have occurred in attempts to apply the method to the extraction of inclusions from alloy steels. The procedure can be used only for the plain carbon steels and for such low alloy steels as those containing the usual amount of copper (0.2 to 0.3 per cent). Steels containing the carbide-forming alloys such as chromium, tungsten, etc., present far too many difficulties for the accurate determination of inclusions. Luckily, the iron and manganese carbides do not offer any difficulties and no contamination of the oxide-sulfide residue results, It is highly probable that some modification of the following

Jan 1, 1931

By V. Panayotov, M. Panayotova

"Finding a reliable relationship between fundamental properties of minerals of non-ferrous metals and their ability to float is extremely important. The approach presented in this work allows us to draw predictive models for an effective flotation, suitable choice of reagents regime and expected technological results before the minerals enter the flotation process. Attempts to adjust the technological regime in already begun flotation are often unsuccessful because the basic physicochemical processes have already taken place. Mineral processing can be optimized on the basis of objective and basic parameters, decisive for the efficiency of the process - the state of the surface of the mineral; assessment of: minerals flotation ability, the need to apply and the type of needed pretreatment, and expected technological results. The theoretical foundations of such an approach are presented in the work, as well as supporting them experimental results, and information on practical implementation in lead-zinc and copper-pyrite ores selection.INTRODUCTIONIncreasing impoverishment of ores of nonferrous metals incoming to the flotation and rising costs for obtaining the final product lead to the inevitable question - will the mineral processing process be beneficial economically, technologically feasible and environmentally safe and what is the way to improve its efficiency. Some of the possible solutions are already in practice - new more efficient and less energy consuming flotation machines and equipment, new - more efficient and selective reagents, new combinations of flotation regimens, and so on.Finding a reliable relationship between fundamental properties of minerals of non-ferrous metals (sulphides and oxides - most of them with semiconductor properties) and their ability to float is extremely important. This is the subject of research, started in the 60s of the previous century and continuing to the present day. Such dependence would enable a realistic assessment of flotation ability (flotability) of minerals before their flotation processing. The basic dependence, displayed by the researchers as Hoberg (1975), Chanturia and Shafeev (1977), Chanturia and Lunin (1983), etc., represents a relationship between bulk properties of minerals and their flotability, considering especially the concentration of the main charge carriers, namely electrons or holes. The bulk properties are practically constant for minerals from a given field. But the 'main arena' of the flotation process is actually the mineral surface (Carta, 1970; Rao, Labonte, & Finch, 1992; Panayotov, 1999; Rao, 2003; Hu, Sun & Wang, 2010). Therefore, we introduce a methodology for studying the surface of minerals, which methodology gives the degree of semiconductor bands bending on the surface and respectively - the charge of the mineral surface and its ability to interact with reagent-collector. The latter can be used to select the most optimal reagent for the corresponding mineral."

Jan 1, 2016

By S. R. Zimmerley, John Gross

"The investigation discussed in this paper was undertaken to obtain fundamental data on crushing and grinding and has been confined, so far, to work on quartz.The results of crushing or grinding have hitherto been judged entirely by the amount of the various-sized particles produced, based. on sieve sizing for particles above 74 microns in size and on microscopic measurement or elutriation for particles below 74 microns - a method which could give only a general idea of what had been accomplished.There was a distinct need of a ""yardstick"" for the measurement of crushed material. It appeared that no advance in the fundamental investigation of crushing and grinding could be made without a reliable method of surface measurement and that such a measurement would have to be based on some property of the surface of the crushed material.A number of attempts based on various surface actions, such as adsorption and heat of wetting, were made to measure surface on quartz particles, but all gave unsatisfactory results. After some preliminary work it was decided that a dissolution method based on Wenzel's law-- ""the reaction velocity between solids and liquids is proportional to the area. of contact""4 -- would be the most feasible.Early use of the dissolution method had been made for surface measurements5, and lately Dr. Geoffrey Martin and his coworkers in England used the dissolution method to determine surface on quartz. They compared the amount of quartz dissolved from a sample in one hour by a hydrofluoric acid solution, with the amountdissolved from a measured quartz cuboid6,After investigating the solvent power of sodium carbonate, sodium hydroxide, and hydrofluoric acid for quartz, hydrofluoric acid was selected as the most suitable solvent, and a dissolution method was developed which gives very reliable results.During the dissolution of quartz in hydrofluoric acid, the reaction velocity changes for two reasons: there is a change in concentration of solution, and a change of surface of the solid. The amount of quartz dissolved in a definite period of time is therefore not a true measure of surface. If, however, the reaction velocity or rate of dissolution for various periods of time be plotted, a curve will be obtained which, if extrapolated to the zero time ordinate, will give the rate of dissolution before any change of surface or any change in the solvent has taken place, and which is a true index of surface. This rate of dissolution, expressed in percentage of the original sample at the zero time ordinate, is designated herein as the ""Initial Rate"" or as simply ""I. R."""

Jul 1, 1928

By Robert L. Lagace

The attention of this group was focussed on four through-the-earth communication systems that are presently of high interest to the U.S. Bureau of Mines; four systems for providing operational/emergency communications on the working sections of coal mines, indeed up to the very face of the section. The systems are: uplink-data, downlink-voice, sidelink-call alert coded page, sidelink-roof bolt voice page. Each of these systems makes use of the mine overburden as the signal transmission medium, as opposed to the guiding wires, cables, and tunnels treated by the operational communications working group. Each of these systems satisfies one or more of the Bureau's objectives for mine communications systems; namely • reliable links for monitoring the mine environment under both operational and emergency conditions. • reliable links for communicating with miners during emergencies. • special links for increasing the efficiency of day-to-day operations of the mine. Each of these systems has been successfully demonstrated on a limited experimental basis, and prototypes of all these systems are installed and operating in the USBM experimental mine in Bruceton, Pa. Each of these systems must now be optimized regarding its performance, and engineered for practical routine application to the working sections of actual operating coal mines, particularly those of the room and pillar type. This optimization and engineering must take place subject to the principal constraints listed by Howard E. Parkinson in his Workshop paper entitled, "Objectives and Constraints of Through-the-Earth Electromagnetic Communications Systems'' and enumerated below. • Depth of Mine Overburden • Overburden Conductivity • Electromagnetic Noise In and Above Mines • Limited In-Mine Electrical Energy (Stationary or Man Carried) During an Emergency • Intrinsic Safety for In-Mine Equipment • Practical and Rugged Equipment for Use Under Both operational/Emergency conditions • Severe Weight Limitations for Man Carried Equipment • Reasonably Low Costs Especially for Man Carried Equipment Part II of this paper provides a brief description of each system, while Part III summarizes the present status of developments related to these systems and some recommendations for future work needed to advance these systems to the practical application stage.

Jan 1, 1973

By C. Matthews, A. Vo

Australia is one of the world’s leading exporters of bulk commodities and the extensive use of sampling equipment is key to the successful management of each mining operation. At the process plant, without a full understanding of the feed, product and tails, it is impossible to fully optimise the performance of the plant, such that the metallurgical balance is often open to error. At the port, a statistically correct, bias free and compliant sampling system is crucial to ensuring exported minerals are reflective of their true value and to avoid penalties. Over the last decade, as a result of the iron ore boom, there has been high demand for reliable, representative and standard compliant solids sample systems in Australia. This paper reviews several solids sampling applications at Australian mine sites, the challenges and experience gained and how the implementation of reliable representative sampling systems has provided better understanding of plant process performance, improved plant control and overall benefits to the operations. INTRODUCTION Mining is the primary contributor to the Australian economy with Australia ranking in the top 4 in economic resources for 21 primary industrial minerals in 2016 (Britt, et al., 2017). Australia is one of the world leaders in the export of the majority of its commodities including gold, copper and iron ore (Britt, et al., 2017). Therefore, a suitable and standard compliant sampling system is essential for evaluating plant performance and content verification. At the mine and at the port, the larger iron ore miners in Australia have developed stockpile models to predict the grade of their ore down to individual blocks of the stockpile. This allows the miner to create the right blend of material for sale to their customers and ensures they are not underselling their product or at risk of penalties for impurities or low grade. As an example, the average difference between the benchmark 62% Fe and low grade 58% Fe fines at the time of this report averaged US $20/tonne according to the Metal Bulletin Iron Ore Index (Fastmarkets MB, 2019). At a shipload of 180kt this would be a variation of US $3.6M. Whilst this is an extreme example, it highlights the economic importance of producing the correct grade product and a recognised representative sample of said product.

Jan 1, 2019

By A. G. Weber, R. L. Ledbetter, A. L. Hicks

A procedure which makes use of both analog and digital computers has been developed for predicting the pressure-production behavior. of water-drive reservoirs. The electric analyzer is used for matching the past pressure and production history of the reservoir and inferring the physical characteristies of the aquifer. When the history has been matched, a .set of base curves called influence functionce" are derived and the future behavior of the reservoir is calculated from these curves. INTRODUCTION Electric analog methods are particularly well-suited for complex water-drive problems. Like all other methods of analyzing water-drive reservoirs, however, analog methods are subject to certain limitations. One of the more obvious and serious of these results from inaccurate or insufficient knowledge about physical characteristics of the reservoir and aquifer. However, it is not insurmountable because the unknown characteristics can usually be inferred from the reservoir's previous behavior. Simons and Spain have shown that even with scant reservoir data and limited production history, electric analyzer studies can provide useful and reliable results. Aside from this limitation on analyzer predictions, the main disadvantage has been lack of a technique for keeping predictions abreast of latest production forecasts. Pressure behavior of a reservoir depends on the rate at which fluid is withdrawn; it is therefore necessary to specify the future withdrawal schedule before the future pressure behavior can be calculated. Conventionally, the electric analyzer predicts pressure behavior for a specific production schedule. If this schedule is abandoned in favor of some new one, as is frequently the case, either the study must be rerun or results adjusted in some manner. The usual procedure is to predict pressures for several different forecasts covering a wide range of production rates. Pressures for specific rates other than those studied can then be approximated by interpolating between the analyzer predicted curves. However, reliability of this type of prediction is doubtful. This paper describes a technique for predicting future behavior of water-drive reservoirs that retains all advantages of electric analyzer analysis and eliminates the main disadvantage. That is, the analyzer is used conventionally to infer unknown reservoir parameters from the pressure history, but not to predict the future behavior directly. Instead, a derived set of base curves, called influence l'unctions, can be used to calculate future behavior for any production schedule.

By J. Poplawski

In mineral processing plants, cyclones typically perform the classification duty prior to the downstream recovery process. Particle size distribution of the cyclone overflow is an important parameter and can be viewed as the product of the comminution process. Too coarse of a product will likely have poorly liberated valuable minerals and make recovery difficult. Too fine of a product may represent a missed opportunity to increase plant throughput and/or also result in low recovery due to poor kinetics. “Near-line” particle size measurement instrumentation has been in place for several decades, its availability and low measurement frequency have typically been inadequate for reliable use in automatic control. CiDRA Minerals Processing has developed a novel and robust technology that provides a highly reliable and low maintenance system for “on-line” measurement of the particle size in the overflow of individual cyclones. The system is based around a wetted sensor design with no moving parts and provides a real-time trend of the desired target grind size parameter. The system does not require sampling and associated sample transfer piping that is prone to plugging, thus avoiding high maintenance requirements. Plant data and benefits realized from the latest installations of the CYCLONEtrac PST will be presented. INTRODUCTION Impact-based real-time hydrocyclone particle size measurement Acoustic impact-based particle size tracking is a unique method for measuring and controlling the particle size in cyclone overflow streams. The implementation of this technology is centered upon a sensor probe that is inserted into the overflow slurry stream via a two-inch (50 mm) hole in the overflow pipe (Figure 1). Particles within the slurry stream impact the surface of the probe generating travelling stress waves within the probe. A sensor converts these travelling stress waves into an electrical signal and proprietary signal processing techniques convert these signals into a particle size measurement that is output every four seconds. The sensor is constantly in contact with many particles in the slurry stream, thus obtaining information from orders of magnitude more particles than traditional sample-based technologies. The sensor has no impact on cyclone performance because it is located downstream of the hydrocyclone and the presence of an air core ensures there is no change in the back pressure seen by the hydrocyclone.

Jan 1, 2019