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By G. Ahuja

Tests were conducted to investigate the effects of cyclone geometry, operating conditions, and particle size on magnetite classification. The effects of these parameters on the partition curve for narrow size fractions were studied using a 25mm diameter cyclone cleaning -150 µ m coal. Additional tests were run to investigate the effects of geometry and operating conditions on the slurry, solid, and water splits. The relationship between the relative density of the underflow stream and the relative density of separation was also investigated. This paper presents the results from this study.

Jan 1, 1994

By David Forrester

"At the 95th CIM Annual General Meeting in Calgary, 1993, a paper entitled “Progress on Futuristic Mining Technologies” was presented(Matthews and Sarin), in which they outlined the goal of continuous excavation of hard rock and some of the technologies being developed to achieve it. The subject continues to be featured in periodic reviews and articles in the literature, (Gertsch, 1994; E&MJ, 1995). Matthews and Sarin note the considerable success of the development and application of continuous mining technologies in the soft rock under-ground mining industry, especially those in coal and potash, with major benefit to overall production, productivity and economic viability. It is the belief that similar achievements can be realised in the underground hard rock mining which continues to drive the development of hardrock continuous mining technology.This overview has been prepared specifically for this issue of the CIM Bulletin. It attempts to tie together current advancements in continuous mining in soft rock (where remote control and automation are already well established) with the background and status of development in hard rock continuous mining. Following a brief review of key factors and machine types, soft rock aspects are discussed, then a more detailed review is given of hard rock technology, with particular reference to Canada’s HRDK Mining Research Ltd. and their key role.The mining industry has long been at the forefront of technology development, for example, the application of the early steam engine to reach reserves at greater depth for dewatering mines in the industrial revolution. By necessity, the individual characteristics of seams and orebodies dictate the mining method, continually presenting mining engineers with new challenges. One of these is the extraction process itself and the goal of replacement of the drill-blast-muck cycle by continuous excavation. Very soft rocks have always been mineable using some form of cutting, even with primative tools. However, as the challenge has been taken up, technologies have evolved to steadily increase the hardness of rock that can be mechanically excavated. It may surprise some readers that at least three machines have successfully cut and loaded rock with an unconfined compressive strength (UCS) of 250 Mpa to 300 MPa (36 000 to 43 500 psi) in field trials (Table 1)."

Jan 1, 1996

By Yu Zhenquan

At the construction site of Bao Shan Iron &. Steel Mill in Shanghai, lots of RC driven piles with length of 50 to 60m were applied. The most unfavourable distribution of stress along the pile shaft was known by measuring the compressive and tensive stresses. With analysing the test results a phenomenon of impact fatigue of RC pile was discovered, the range of impact fatigue and its critical zone can be distinguished. Finally some countermeasures are presented to avoid the impact fatigue of RC long pile.

Jan 1, 1991

By A. J. Vivyurka

"This is a talk about the experiences that Rio Algom Mines Ltd. has had in the Elliot Lake uranium area trying to make the tailings more compatible with the surrounding environment. To get a better idea of the problem that we are associated with we have to go back to the location. The Elliot Lake uranium area is situated about half way between Sault Ste Marie and Sudbury and is about 20 miles north of Lake Huron. In 1950, uranium was discovered along the north shore of Lake Huron and by 1961 we had up to 9 mines operating in the area. Then the United States Atomic Energy Connnission withdrew their contracts so that at present there are only 2 mines operating. From all the mines that we had operating, we ended up with 7 tailings areas. From these 7 tailings areas we have 5 sites where we have active treatment or rehabilitation. There is the Pronto site where we are treating uranium tailings and copper tailings. There is the Lacnor-Nordic site which is located just out of Ellio Lake. The Milliken-Stanleigh site is in the Crotch Lake area. The Panel tailings is off the north end of Quirke Lake and finally there is the operating property of Rio Algom Mines at Quirke Lake.To understand fully the problem with this rehabilitation we have to look at the constituents of the ore. The ore body is a quartz conglomerate with uraninite and brannerite as the uranium bearing minerals in a fine ground mass of quartz, sericite and pyrite which separates the larger quartz pebbles. The approximate composition of the ore is: 80% quartz, 13% chlorite, 7% pyrite and 0.2% uranium minerals. The processing method also adds a few constituents to the final tailings."

Jan 1, 1975

By L. Jurca, C. Gligor

After 1990, a great process of re-organisation and economic reform has occurred in the Romanian mining sector and especially in the pitcoal mining in the Jiu Valley. This process has included both legislation and the main aspects for getting an economic efficiency in the environment issues and for dealing the problems with social impact. Accordingly, starting with the year 1993 a new mining method has been introduced to turn efficient the pitcoal mining, and we speak about mining with caved in bed. This method has two variants: - with transverse strips and caved in bed; - with long face and caved in bed. Each of the above-mentioned variants has in turn several subdivisions, depending on how the longwall is prepared and on other characteristics. By using this method, the output has increased compared to other mining methods. The main safety aspects concerning caved in mining refer to: - great emissions of methane; - technical aspects (a mining method system, supports, discharging process); - pressure driving (analysed for the case of mining with long face, with transverse strips as well for the case of transverse strips when mining a subsequent sublevel).

Jan 1, 2003

By Sarracino R. S

A number of ideal detonation codes are used internationally for estimating the strength of explosives compositions. Important and far reaching decisions by explosives users are ofen based on the predictions of these codes, but since different codes can deliver very different answers for the same composition, there is a strong possibility of decision makers being misled. In order to both provide a sensible basis for comparing the theoretical energy from explosives from different manufacturers and to prevent the entire rating system from slipping into disrepute, it is in the interests of all to reach agreement on fundamental criteria used by detonation codes for detemtining strength. The problem is illustrated by a case history and basic conventions are proposed, specifically the adoption of energy of reaction as a fundamental and code independent indicator of explosive energy, and agreement on disclosure by suppliers of key non-proprietary information. These measures would assist explosives customers in assessing the true strengths of explosives from the strengths calculated by the different ideal Codes.

Jan 1, 1990

By C. H. Benedict

Largest and most important of the milling plants under construction during the year is the Morenci plant of the Phelps Dodge Corp., in Arizona, where plans are being rushed for production in 1942. Grate mills will be used for fine-grinding, and in the pilot plant, classifiers of the spiral type have the preference for the closed- circuit work. The flotation units will be chiefly of the pneumatic type, with some mechanical units as auxiliaries. The Fagergren, Pan American, and Agitair machines were left in the competition as the year closed. If the absence of European markets for finished products has dislocated the mining industry, fortunately the lack of raw materials required in the beneficiation of ores has not been serious. except possibly as to the inability to import flint grinding pebbles. Some of the less important gold mines still use pebbles for grinding as is also the practice in the comminution of nonmetallics used in various industries. T the Calumet & Hecla in the Lake A Superior copper district pebbles have been used exclusively in open- circuit grinding in the Hardinge mills treating the

Jan 1, 1941

By Arthur Matzick

The oil shale from the Mahogany zone of the Green River formation in northwestern Colorado has the greatest potential in the United States for early utilization. A large reserve of adequately rich shale is available to support a sizable industry, and crushing of tremendous tonnages will be required if conventional processing methods are used. This report presents Bureau of Mines data on crushing experiments, physical properties, and related information for Colorado oil shale. Among the properties important to crushing are slab-forming tendency, resilience, slippery character of the richer grades, and heterogeneous nature of an average charge of Colorado oil shale.

Jan 1, 1960

By Pedro Vargas Gálvez

El presente texto señala la metodología de selección del software de mantenimiento respecto a este mismo y a la Planta. Para ello, se detalla las condiciones que deberán considerarse en la Organización de Mantenimiento y la aplicación del Software de Mantenimiento MP2 a una empresa. Asimismo, se presenta el Plan de Implantación, los inconvenientes que se han encontrado así como los resultados obtenidos por la utilización del Software MP2.

May 25, 1998

By P. T. L. Koh, M. P. Schwarz

A series of parametric studies were carried out for a flotation cell using computational fluid dynamic (CFD) modelling to determine the local response of hydrodynamic performance measures to change in operating conditions. As an example, an Outotec cell was used to carry out the response analysis. The hydrodynamics of the flotation cell has been previously investigated by laboratory measurements presented by Schwarz et al (2019), and a CFD model of the cell was developed and validated using these measurement data (Schwarz et al., 2019). In this work, parametric studies have been performed by modelling the flotation cell at different stirring speeds and gas flowrates, varying above and below standard conditions. Predictions of void fraction, bubble size, bubble surface area flux and particle–bubble collision rate are presented showing the effects of increasing and decreasing stirring speed and gas flowrate around the base case. Generally, the total gas holdup in the flotation cell was found to increase with increasing gas flowrate. The bubble diameter was found to decrease with increasing stirring speed and increase with increasing gas flowrate. The collision rate increased with both stirring speed and gas flowrate. The parametric results show that there is a correlation between the bubble surface area flux Sb which is affected by stirring speed and gas flowrate, and the particle–bubble collision rate. With the collision rate as an indication of flotation collection, it is also possible to show that cell performance can improve more by increasing stirring speed than by increasing gas flowrate in a situation where everything else remains constant. The CFD results can form the basis for a Response Surface Method (RSM) analysis which can then be used for automated optimization of cell performance. Keywords: Flotation kinetics, computational fluid dynamics, bubble surface area flux, particle-bubble collision rate

Jan 1, 2020

By F Palkovitz, S Wilson, F Felipe

The management of waste from mining operations is a significant aspect of bringing a mineral commodity to final market. The ore beneficiation process and transport/disposal of waste involves significant consumption of costly resources. A number of options exist to dispose of mill waste on surface and as a backfill material. These range in complexity, risk, capital cost, operating cost and ultimately business performance. This paper discusses the value delivered to a business in using dewatering systems including paste as opposed to conventional slurry tailings disposals. This is illustrated through various case studies and serves to demonstrate how paste can add value and reduce risk to a successful business.

Jan 1, 2009

By Andrew R. Marchbank

The application of biologically assisted methods for metal extraction in the mining industry has a long history, but development of modern techniques has been relatively slow. There is, however, a resurgence of interest in the industry with the recent development of methods to successfully treat base metals concentrates. Two major pilot plant programs for treatment of chalcopyrite concentrates have been initiated in the past year and results from one are beginning to be released. This paper provides an overview of methods that have been applied in the past; from the earliest deliberate applications of the technology, through the copper and uranium heap and dump leach applications, the more highly engineered agitated tank leach gold applications and the developments currently taking place in the industry.

May 1, 2002

By Raymond A. Bradbury

A significant news item appearing in a coal mining journal in November 1969 stated simply that a Caterpillar D-333-CNA engine had received Bureau of Mines Schedule 31 approval. This item occurring at the time a new mining property in Martin County of East Kentucky was being prospected and prepared for mining, resulted in the manage-ment of Martin County Coal Corporation asking the question, "Why not use diesel equipment in our new operation?" Martin County Coal Corporation is part of the A. T. Massey Coal Company, Incorporated organization. The property being developed is on a 17,500 acre leasehold obtained from Pocahontas Land Corporation and lies in the Wolf Creek area of Martin County. The Norfolk and Western Railway Company built a 24-mile railroad into this undeveloped section of Kentucky to tap a huge reserve of steam coal. Duke Power Company is the customer who will take all of the production from Martin County Coal Corporation mines which ultimately is projected to be 2,000,000 tons annually. Four coal seams, all above drainage, are included in the lease. The Middle Coalburg and Stockton are being deep mined now and it is in those mines that the diesel haulage equipment was introduced. This paper will endeavor to trace the steps loading to the introduction of the first diesel-powered Wagner Mining Equipment Company ScoopTram in a coal mine in America. It will further elaborate on the features which make this unit a very versatile and useful utility unit as well as the safety features which are incorporated in the machine. The success of this first unit led to the placing of

Jan 1, 1972

By L. H. Cole

Introduction The increasing importance of the gypsum industry in Canada is evidenced by the fact that the production has increased from 473,129 tons valued at $809,632 in 1909 to 1,205,846 tons valued at $3,622,007 in 1928, an increase of over 155 percent in quantity, and of 347 percent in value, in the 20-year period. Although the export trade in crude gypsum still forms a large proportion of the industry, it is gratifying to see that the home consumption is steadily increasing, and while the percentage of the crude gypsum mined that is manufactured into the calcined products in the country is only 16.8 per cent, its value is practically 50 per cent of the total gypsum production of the whole country. It is to be hoped that each succeeding year will see an increase in the amount manufactured in Canada, and, with the steady growth of the country and a serious endeavour to capture a part at least of the world market in gypsum products, the outlook for the industry is decidedly promising. The value of gypsum as a commercial commodity has been known from the time of the early Egyptians; in fact its value for certain purposes has been known so long chat the date of the discovery of its peculiar properties is unrecorded.

Jan 1, 1930

By T. R. Ellis

The vast majority of valuations produced for mineral properties using the net present value method provide an estimate of Investment Value or Use Value. Such an estimate can be a long way from the price that the property would sell at if placed on the market. Indicators from the market need to be used to validate or modify the net present value calculation. The comparable sales and replacement cost approaches used in the appraisal of urban buildings generally fail us in the appraisal of mineral properties. Other methods of sales analysis are introduced. Guidelines for what a minerals appraisal report should contain are presented.

Jan 1, 2000

By J Weir

Accurate sampling of slurry streams is extremely important for metallurgical accounting in mining operations, not only for measuring the ore grade from the mine, but also for measuring the recovery of mineral by the mineral processing plant. Accurate sampling is also required for intermediate streams in complex circuits for determining efficiencies of processing units within the plant. As the profitability of the minerals industry is squeezed more with time, greater emphasis is being placed on efficient use of the resource and accountability of the various sections of the mining operations. This has led to increased awareness and interest in obtaining statistically correct sampling across the operations. Accurate sampling is not only required for metallurgical accounting, but is also required for on-line analysis of the slurry streams for elemental analysis and for particle size. Sampling of slurry streams for metallurgical accounting purposes has traditionally been one of the areas of concern in mineral processing plants. In the first instance, the sampler must be designed to comply with the fundamental principles of sampling theory and must provide a representative sample of the slurry stream. In the second instance, the sampler must continue to reliably provide a representative sample, regardless of wear of the equipment or build up of solids with time and other operating issues. To-date the main type of sampler that has been used in mineral processing plants for metallurgical accounting has been the Cross-Cut sampler. These have a cutter that periodically cuts across the full slurry stream. For large flow slurry streams, these are often followed by a secondary and perhaps a tertiary sampler, to reduce the flow-rate or sample, to a manageable size. This paper discusses a new method of sampling slurry streams that has been developed by Thermo Gamma-Metrics, previously known as Amdel Instrumentation. The new samplers overcome many of the problems associated with cross-cut samplers while providing a sample which is representative of the main stream, throughout the life of the sampling system. The sampler is called the SamStat (Sampling Station) and it is now proven in many applications across many countries and mineral processing plants (PGMs, Cu/Au, Pb/Zn, etc).

Jan 1, 2002

By S. Banisi, M. Poorkani, M. Farzaneh, M. Askari

"At the Sarcheshmeh copper mine 40,000 t of ore per day with an average grade of 0.9 % Cu is ground to 70% passing 75 microns. Grinding is effected in 8 parallel lines of 8 x 5 m ball mills in a closed circuit with cyclones. The make-up balls are 80-mm forged alloy steel balls and the average ball consumption is 750 gh of ore ground. In order to optimize ball size distribution inside the mill, based on the previous investigation instead of using only 80 mm make-up balls a combination of 80 and 60 mm (75% to 25% by weight) ball charge was used in one of the mills. To evaluate the performance of three ball types namely forged alloy steel balls (A), ductile cast iron (C), high chromium cast iron (D) and also a combined (80 and 60 mm) charge of forged alloy steel balls (B), four identical parallel mills were charged accordingly. These four mills were sampled during a period of six months. The amount of material finer than 75 microns of cyclone overflows was selected as a criterion for the performance evaluation. It was observed that in a mill with the combined make-up balls the amount of fine produced was 4% higher than the other mills. The consumption of ball types A, C and D were 730, 710 and 534 g/t, respectively. The results of laboratory flotation tests showed that due to an improvement in the production of fines an increase of 1.4% in the overall copper recovery is obtainable. Due to the promising results, the new make-up ball regime was implemented in all mills in the plant.INTRODUCTIONThe Sarcheshmeh copper ore body which may rank as third or fourth largest in the world contains 1 billion tonnes averaging 0.90 % copper and 0.03 % molybdenum. It is located southeast of Iran and has been processing 40,000 t/d of ore since 1982. The mine produces 100,000 tonnes of copper and 2,200 tonnes of molybednite concentrate per year. After three stages of crushing, the ore with a F80 of 12.7 mm is fed to 8 parallel ball mills in closed circuit with cyclones to produce a product 70% finer than 75 microns. The concentrate of the first stage of flotation is reground and the tailing constitutes the main component of the plant final tailings. A concentrate with an average grade of 31% Cu is obtained after cleaning and re-cleaning stages. Total recovery of the plant varies between 83 and 87 % depending on the operating conditions and ore type."

Jan 1, 2002

By Willard L. Hunter

The smelting of tin slags was undertaken at the Bureau of Mines Albany Metallurgy Research Center (AMRC) to produce crude columbium-tantalum ferro-alloy as a unit operation in the production of pure columbium and tantalum oxides or chlorides. Columbium and tantalum-rich alloy was prepared during short unrelated campaigns over a total period of 12 years. Tin slags from Malaya and the Congo (Geomines) were smelted. These slags were reduced by carbon in a small, single-phase, steel-making furnace} a larger three-phase, steelmaking furnace, and a three-phase, submerged-arc furnace, In all cases depleted slags were fluid and easily tapped from the furnace. However, unless diluted by iron additions, the metal product was a viscous, high-melting, heterogeneous mixture that could be removed from the furnace only by hand rabbling.

Jan 1, 1966

By D. F. Smith

The thermodynamic data presented in the literature for zirconium compounds are incomplete. Among the compounds for which adequate data are Zacking are zirconium fluoride and sulfate. This paper reports experimental heat-content values determined by the Bureau of Mines for these two zirconium salts throughout the temperature range of 273° to 1,200° K. No crystalline transformations were found in the two compounds investigated, and neither of the compounds melted over the temperature range studied. MATERIALS TESTED The Oak Ridge National Laboratories, Oak Ridge, Tenn., supplied the two zirconium salts used in this investigation. The zirconium fluoride was high- purity reactor grade material. The zirconium sulfate contained between 0.01 and 0.10 percent hafnium and calcium, and other elements in concentrations below 0.01 percent, A spectrographic analysis of the two compounds is given in table 1. Before use the compounds were dried at 400° C. for several hours to removed adsorbed moisture.

Jan 1, 1962

By Carl Erickson, James Hislop

INTRODUCTION As practiced today, longwall mining is a mechanical version of an established mining system. The equipment for longwall mining consists of four basic units: roof supports, face conveyor, winning or mineral-getting ma¬chine, and stage-loader conveyor. The system mines relatively thin slices of mineral across a predetermined face length in a virtually continuous sequence. As the winning machine cuts, the mineral is loaded automatically onto the face conveyor. In turn, the face conveyor is pushed over into the newly cut track by hydraulic rams attached to the conveyor and the roof supports. The roof supports then are lowered individu¬ally from the roof, advanced to the repositioned con¬veyor, and reset to the roof. At the end of the pass, the longwall cutter is pushed over, and a slice is taken in the opposite direction, so the system repeats itself. Fig. I illustrates a typical longwall mining system. The principle behind the longwall mining system is that the roof is supported only immediately adjacent to the worked seam, keeping the blocks of immediate roof clamped securely from the face to the rear of the sup¬ports. At the rear of the supports, the roof is allowed to fall and break up, with the swell of the broken material eventually establishing an equilibrium in the strata be¬hind the mined area. Fig. 2 illustrates the principle of longwall support. There are two distinct types of longwall mining. The longwall retreating system is the most common in the United States, South Africa, and Australia. The longwall advancing system is the most common in the re¬maining industrialized countries such as Britain, Ger¬many, Poland, and the Soviet Union. The longwall retreating system comprises a mining panel, where the roadways that form the head entry (end at which mineral is delivered from the face con¬veyor to a stage-loader conveyor) and the tail entry are predriven before the longwall units starts production. In the longwall advancing system, the longwall unit makes the head and tail entries as the face advances, utilizing various techniques to prevent the entries from being destroyed as they are left in a consolidating gob area. Fig. 3 illustrates the comparative approaches of the longwall retreating and advancing operations. As with most other underground mining systems, there are many variations on these two basic systems, using combinations of the systems that are dictated by

Jan 1, 1982