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By William Catron

This paper is one of a series being prepared by the United States Bureau of Mines on mining methods, practices, and cuts in the various reining districts of the United States. The mining methods described are those used in the mines of the Cananea Consolidated Copper Co., a Mexico corporation whose holding company in the United States is the Greene Cananea Copper Co. The mines are at Cananea, Sonora, Mexico, 25 miles directly south of the international boundary, approximately in 31° nor to latitude and 110 to 130° west longitude. Cananea is connected with the boundary towns of Naco and Nogales, Ariz., by a standard-gage railroad.

Jan 1, 1930

By L C. Taylor

Both the U. S. Navy and the U. S. Army are interested in knowing more about the loading applied to vehicles which are unfortunate enough to encounter a detonation of a buried mine in the course of performing their normal duties. The Dynamic Effects Laboratory at the University of Maryland has been involved in small scale testing for ten years to assist the Navy and the Army in understanding the loads that are applied to personnel carriers when a buried explosive detonates beneath them. This paper describes results from small scale tests conducted to determine the loading mechanisms on target plates when subjected to loading due to the detonation of a buried mine in saturated sand, dry sand, and water. Transparent target plates were utilized in order to determine the loading process beneath a floor board on armored vehicles. Various charge sizes were scaled in the laboratory accordingly to a standardized full size threat encountered in the battlefield. Tests were conducted in saturated sand, dry sand, and water keeping the stand-off distance of the target and the depth of burial of the charge constant. In the case of water impacting a transparent PMMA plate the crack propagation was recorded and the crack velocity is determined. Additional tests were performed in saturated sand by varying the stand-off distance of the target but keeping the depth of burial of the charge constant. The small-scale test results could be scaled to full scale by using verified scaling laws.

Jan 1, 2016

By P. Lafleur

All indications point to a growing market for thermal coal in Japan as part of the country's current energy policy formulation process. The Ministry of International Trade and Industry forecasts imports of 16 million tons a year in 1985 and 40 million tons in 1990-a twenty-fold and forty-fold increase over the present level. This potential reflects Japan's over-all serious and increasing concern for security of energy supplies and its resultant need to seek alternative sources. Nuclear power will be the main alternative source, but, because it is expected that its development will be slow, imported thermal coal will assume greater importance. Canada, with large resources of all types of coal, could fill a portion of this market. Thermal coal could come from specific thermal coal developments or from metallurgical coal mines, which usually produce a certain amount of coal not amenable to coking, but suitable for power purposes. However, penetration of this Japanese market by Canadian thermal coal will depend on the resolution of a number of problems. On the demand side, siting, environmental aspects, the need for a coal unloading and trans-shipment centre, and the added cost of installing coal-fired stations could be major constraints. Although Canada has ample high-quality resources, any new development tied to the Japanese market will require improvement in prices to cover the high costs associated with transportation, the construction of new mines and the provision of new infrastructure.

Jan 1, 1979

By A. Hartikainen, M. Rinne, F. Johansson, R. Yorke, L K. T. Uotinen, E. Korpi, J. Antikainen

"In order to determine the in-situ shear strength of rock joints, large scale testing is required. However, this is both expensive and difficult to execute. One possible method to overcome this may be to use photogrammetry to capture large joint surface roughness in-situ and downscale it to replica samples, which could be sheared in laboratory. In this paper, as a first part in such a method, a technique to digitize surface roughness and to produce replica samples for laboratory shear testing from a larger joint sample are presented. First, a thin granitic rock slice with dimensions of 1.75 m x 0.95 m of granitic intact rock was chosen for the study. The joint surface is fresh and created through tensile induced splitting. The large joint sample is digitized using photogrammetry. Then, one fullscale 1.7 m x 0.6 m geometry is cropped from the digitized joint geometry and then subsamples at 10x, 7.5x, 5x, 2.5x and 1x scales. All sub-geometries are scaled down digitally to produce 0.17 m by 0.06 m geometries. The geometries are used to make casting molds both positive and negative to produce samples with perfect matedness. The casting molds are 3D printed in polylactic acid plastic and C60/75 concrete is cast to produce a replica series. In addition to the creation of this replica series, two pilot replicas are also tested using a portable shear box with a 0.5 MPa normal pressure. The results from the pilot rounds are presented and discussed. Finally, suggestions for future research are given.INTRODUCTIONThe rock mass strength is in many cases controlled by the shear strength of rock joints, especially in hard rock masses. The shear strength is generally found to be influenced by several parameters, including normal stress, the basic friction angle of the intact rock, the joint surface roughness, the joint wall compressive strength, the matedness of the joint surfaces, weathering and infilling. The effect of these parameters for the joint shear strength can be evaluated in laboratory scale. However, the shear strength is known to be scale dependent. How the scale effect influences the strength is not fully understood. The general consensus is that the shear strength decreases when sample size increases, i.e. a negative scale effect (Bandis et al. 1981). However, some studies have presented contradictory results, see for example Hencher et al. (1993) and Kutter & Otto (1990). The extent and nature of the scale effect is still a question of debate (Tatone & Grasselli 2013)."

Jan 1, 2015

By J. J. DeMull, B. A. Boster

Amax's Sleeper mine uses conventional cyanidation milling and heap leaching techniques to produce gold. Since milling operations commenced in March 1986, average ore processing rates have improved from the design rate of 455 t/d (500 stpd) to more than 720 t/d (795 stpd). Heap leaching was added to the process facilities in September 1986 at a design rate of 1.5 kt/d (1650 stpd) and current heap leaching rates exceed 2.7 kt/d (2950 stpd). Presented are descriptions of the Sleeper processing facilities with emphasis on the crushing and grinding circuits, a review of the selection of crushing and grinding equipment, and a summary of operating performance during the first 16 months of operations.

Jan 1, 1990

By Ralph H. Espach

Wyoming contains many petroleum and natural-gas fields, and more than 250 geological structures have been mapped; however, only about 85 have been found (July 1938) to contain petroleum or natural gas, or both, in commercial quantities. To January 1938 approximately 434 million barrels of oil and 915 billion cubic feet of gas have been produced, and it was estimated that proved oil reserves in Wyoming amounted to 300 million barrels.' The Salt Creek field, the largest in the Rocky Mountain area, alone has produced 64 percent of the State's oil and 46 percent of its gas. This field ranked thirteenth among the producing fields of the United States in total cumulative production as of January 1, 1938. On this basis it ranks with the Kern River and Huntington Beach fields of California and the Butler County fields of Kansas. The Salt Creek field has declined in relative importance; in 1937, while still the largest oil-producing field in the State, it produced 31 percent of the oil and 11 percent of the gas extracted from all wells in Wyoming.

Jan 1, 1941

By James O'Brien, Lyman Frost, S. Elangovan, J. Stephen Herring, Joseph Hartvigsen, Carl Stoots, Anthony Nickens

"Carbon dioxide recovered from concentrated sources, such as metallurgical reduction furnaces, cement kilns and fossil power plants can provide a valuable feedstock for a synthetic fuels industry based on energy from nuclear, solar, wind and hydropower sources. High temperature co-electrolysis of CO2 and steam to produce synthesis gas has been demonstrated using reversible solid oxide fuel cell technology. Where a source of high temperature process heat is available, such as from an advanced high temperature nuclear reactor or solar dish concentrator, the endothermic electrolysis reactions can utilize both thermal and electrical inputs in such a way that the conversion efficiency within the cell is 100%. Synthesis gas produced in a coelectrolysis cell has been further reacted over a catalyst to produce conventional hydrocarbon fuels. Widespread implementation of synfuel production from CO2 will enable a much larger reliance on intermittent renewable energy than can be accommodated by conventional electric demand profiles.IntroductionFor the past several years, Ceramatec, Inc and the Idaho National Laboratory (INL), have been studying the feasibility of high temperature solid oxide electrolysis for large-scale, nuclearpowered hydrogen production under the U.S. DOE’s nuclear hydrogen initiative (NHI) as an alternative to the thermochemical process. Parallel to this effort, the INL and Ceramatec have been researching high temperature co-electrolysis of mixtures of steam and CO2 to produce syngas:"

Jan 1, 2008

By A. Uiga

The U.S. Bureau of Mines funded a project which addressed objectives concerning irrigation of native plants and inoculation of native plants with vesicular-arbuscular mycorrhizal (VAM) fungi. The specific irrigation objectives were 1) to demonstrate the performance capabilities of solid-set irrigation for reclaimed mineland conditions, and 2) to demonstrate and evaluate three irrigation concepts under two separate water supply conditions. The VAM inoculations were to assess irrigation benefits in establishing VAM relationships for transplanted native species. Following the seasonal demonstration (May to September 1983) at 3 separate mine sites, conclusions were made that apply to the 6 state Western mining industry. The demonstration sites were located in Montana, Wyoming, and New Mexico. Positive conclusions were reached for 1) the use of soil moisture sampling with or without irrigation, and 2) the selection of solid-set sprinklers as the irrigation method. The conclusions about the irrigation concepts and strategy were mixed, due to the short-term (1 season) nature of the project. No conclusions could be reached for the VAM inoculations because the study time was too short.

Jan 1, 1984

Arsenic.--Inorganic arsenic has been added to the Environmental Protection Agency's list of hazardous air pollutants because of a high probability it can cause cancer. EPA estimates that inorganic arsenic emissions into ambient air total more than 6,000 tons per year, with about 65;L of this coming from the operations of copper, lead, and zinc smelters. Asbestos Detection.--In June 14, the President signed S. 1658 providing $172.5 million to detect and remove asbestos hazards in schools. Asbestos Use Must be Reported.--All firms using asbestos in the manufacture of some 30 categories of products must describe in detail how they use the mineral to the Consumer Product Safety Commission, for all manufactures since January 1, 1977.

Jan 1, 1980

By R. G. O'MEARA, Alexander M. Gow, W. T. SCHRENK

Lime is used extensively in the various industries. The National Lime Association in an excellent and recent bulletin lists 23 important in- dustries in which lime plays a vital role; and it thereby justifies the statement that "Lime is one of the most versatile and widely used reagents in the chemical and industrial world." There is, however, one application of this "universal" reagent which has not been mentioned. It is the use of lime in the flotation of ores. An appreciable percentage of the lime produc- tion is consumed by ore-dressing plants. The uses of lime throughout all the industries are more or less re- lated, but "lime" is a broad term; the varieties of lime are more mumerous than the limestones from which it is made, and its use involves a complicated technique. The interrelated application and growing importance of lime in flotation warrant this additional publication on the various "limes," with emphasis on those uses related to the function of lime in flotation. ཁྐྲ་ Lime in water treatment, cyaniding, and amalgamating will be men- tioned, after which its use in flotation will be taken up. This compendium was prepared by the Mississippi Valley Experiment Station of the United States Bureau of Mines and the Missouri School of Mines and Metallurgy, Rolla, Mo.

Apr 1, 1931

By Persifor Frazer

1. SMOKE PREVENTION. Report of Select Committee of House of Commons (1843). Nuisance considerably abated in Leeds (Wm. Backerd, July 13, 1843, 239 pages). A synoptic index, p. 211, gives, in alphabetical order, the digest of every subject taken up. 2. FUEL : ITS COMBUSTION AND ECONOMY. D. Kinnear Clark, C. E. 24mo, 1354 pp. Crosby Lockwood & Co., London (1880). Includes abridgement of treatise on combustion of coal and prevention of smoke, by C. W. Williams, A.I.C.E. 3. DIE RAUCHSCHÄDEN IN DEN WÄLDERN DER UMGEBUNG DER FISCALISCHEN HÜTTENWERKE BEI FREIBERG. Dr. J. v. Schröder, Professor in Tharand, and Dr. A. Schertel, Vorstand des Hüttenlaboratoriums zu Freiberg. Royal 8vo, 27 .pages, 19 pages of tables and a map. Ernst Maukisch, Freiberg (1884). (Aus dem Jahrbuch für das Berg- und Huttenwesen, 1884.) In 1861, Reich and Stockhardt examined the extent of injury to vegetation by the Muldner works. Needles and twigs of pine showed in 100,000 parts : Pb, 5 to 50 ; As, 3.3 to 14.3 ; S02, 62 to 120. In the top twigs, 5 to 8 ; needles, 10 to 16 ; thicker twigs, 10 to 22 ; thinner twig-ends, 17 to 54 of lead. Lead greater in amount in sickly twig-ends with few needles ; also in the bark than in the naked wood of the trunk, which had hardly a trace ; also in the part turned toward the works than on the opposite side. Pb and As diminished in the vegetation with distance from the smelter ; and the same with regard to the soil. Fresh snow was collected, and SO, As, and Pb detected in it.

May 1, 1907

By M Bilodeau, G Caro, R Beaudoin, D Labrie

In 2005, Dyno Nobel Canada Inc, DynoConsult and CANMET-MMSL used their pool of expertise in blasting, ground control, open pit and underground mining, mineral processing, information technology and applied mineralogy to launch a research project aimed at evaluating the role of electronic detonators in the development of a sustainable energy-efficient rock reduction process. The overall objectives were to improve health and safety in a mining environment and reduce energy consumption and greenhouse gas (GHG) production in the Canadian mining industry. The study was conducted in a quarry located in Nova Scotia, Canada, with the objective of taking advantage of the higher accuracy and flexibility of electronic detonators towards improving blast efficiency and measuring its impact on productivity in a quarry environment and energy savings. Optimising the blast sequence was the first aspect to be considered before starting to look at designing bigger blasts and achieving productivity improvements, without creating additional environmental concerns, as the quarryÆs location was representing a challenge in itself in the surrounding community. The use of high-speed cameras (500 fps) was an improved means of analysing blast dynamics during the firing sequence. Seismic monitoring and linear superposition techniques were also applied to validate the sequences to be tested in all three specific geological areas. The combination of field measurements allowed to identify the optimal blasting sequences that would then be delivered accurately with the electronic initiation systems. The data from 12 blasts (six with electronic detonators and six with pyrotechnic detonators) carried out in three different geological formations (soft, medium and hard rock) showed that the electronic blasting technology could increase rock fragmentation by 15 to 20 per cent. A more uniform distribution of rock fragment size was also obtained. Blast improvements on downstream processes resulted in a five per cent productivity increase in rock excavation and transportation, a ten per cent energy reduction in primary crushing and a 15 per cent increase in the primary crusher throughput. A prototype soft-sensor based on primary crusher data (eg energy consumption, throughput, feed and product size distribution) and a simplified computer process model were developed for online measurement of a rock operating work index. Furthermore, rock samples were collected and specimens were prepared in order to determine the tensile and compressive strength of the rock materials, evaluate the aggregate crushing work index and examine the development of micro and macro-fractures under binocular and scanning electron microscopy (SEM). Blast-induced rock damage was evaluated at the end of the laboratory testing program. A reduction in rock hardness by about 30 per cent was observed after blasting. However, the impact of the blasting method (eg using electronic versus pyrotechnic detonators) on the induced rock damage was either absent or not perceptible within the measurement technique accuracy and the number of samples analysed.

Jan 1, 2007

By E. Wittenau

This paper describing the concentrator practice of the Copper Queen Branch of the Phelps Dodge Corporation at Bisbee, Ariz., is one of a series of papers on milling methods and costs being prepared by the United States Bureau of Mines. The Copper Queen Concentrator treats 4,000 tons of copper ore daily by preferential flotation, whereby the copper sulphides are floated and considerable iron pyrite is depressed. During 1929 the heads to the concentrator averaged 2.15 per pent of copper, the recovery was 91.32 per cent of the total copper, and the concentrates produced contained 12.92 per cent of copper.

Jan 1, 1931

By L Eriksson, D Penn, J Appelgren

Atlas Copco, a leading supplier of equipment and services to the mining and construction industries, is consistently pursuing its strategy to offer the most productive and economical solutions by continuously offering new innovative products. These are, in most cases, developed and tested in close cooperation with demanding end users before being officially launched on the international market. The demands for higher productivity and improved overall economy have resulted in systems for automation of the drilling cycle and also tools for integrating the drilling equipment to the production control system used by the customer. In terms of improving the blasted material quality, the company has placed emphasis on accuracy in the drilling process and documenting what has been drilled. By applying state of the art technology to the common automation platform, developed for the surface drilling market, major steps in improving overall drilling productivity and blasting performance have been achieved. This paper will give some examples derived from the latest development of solutions for the companyÆs surface drilling products.CITATION:Appelgren, J, Eriksson, E and Penn, D, 2012. Rotary drilling automation increasing operator productivity and drilling quality, in Proceedings Eighth Open Pit OperatorsÆ Conference , pp 13-18 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 18, 2012

By M. Kermani

This paper presents and compares the physical properties of Gelfill and cemented hydraulic fill (CHF) obtained by lab experiments. Gelfill has an alkali activator such as sodium silicate in its materials in addition to primary materials of cemented mine backfill which are deslimed tailings, water and binders. The CHF and Gelfill samples with various mixture designs were cast and cured for 28 days. Initially, the influence of sodium silicate concentration on the mechanical properties of samples was evaluated using the unconfined compressive strength (UCS) test. Consequently, the effect of curing temperature on CHF and Gelfill samples cured in various curing temperatures ranging from 5?50 °C was studied using the UCS test. Microstructure of selected samples was studied wirth the mercury intrusion porosimetry (MIP) technique. This study concludes that: (i) The mechanical properties of CHF can be improved by the addition of appropriate amount of sodium silicate. (ii) The rate of strength acquisition in Gelfill samples is faster than CHF samples over 28 days of curing period. (iii) Curing temperature strongly influences the mechanical and microstructural properties of CHF and Gelfill samples. (iv) The microstructure analysis revealed that the addition of sodium silicate can modify the pore size distribution and total porosity of Gelfill which can contribute to the better mechanical properties of Gelfill. (v) The MIP tests suggested the microstructure of specimens were changed by adding sodium silicate in a way that the Gelfill samples had a higher percentage of fine pores than CHF samples.

Aug 1, 2013

By J. B. Yianatos

A practical an interactive model to describe the operation of a flotation bank of mechanical cells was developed based on the hydrodynamic and metallurgical characterization of large industrial flotation cells. Thus, the mineral grade and recovery, as well as the stream properties along the flotation bank can be described in terms of the operating variables. The model was built considering the flotation bank as a distributed system, so the solution for the water and solids mass balances, per size classes, for each single cell, are sequentially solved. Also, each cell was described by two distinct zones, the collection zone characterized by the flotation rate constant and the froth zone characterized by the froth recovery. The mineral feed was described in terms of the mineral species and particle size classes, using a rectangular flotation rate constant distribution. Also, the effect of changing the actual operating variables (air flowrate, pulp level, pulp density, pulp flowrate, etc.) on the mineral collection process, in the collection (pulp) zone, was considered downstream along the bank. The froth recovery of floatable mineral has been estimated by measuring the mass flowrate of particles entering the froth by true flotation together with the concentrate mass flowrate (ton/h). The mass flowrate of collected particles at the pulp/froth interface level was calculated from direct measurement of bubble load (ton/m3) and gas flowrate (m3/h). Flotation recovery is mainly related to the froth depth and air flowrate. All parameters considered in the model have been adjusted from direct measurements in plant site. Also, the effects of other operating variables such as reagents dosage, top of froth grade, or froth discharge velocity are presently under study. This procedure has been tested using data from industrial rougher operations consisting of flotation banks with 5 cells to 9 cells in series, and different cell sizes, such as 45m3, 130m3, 160m3 and 250m3. Thus, it has been shown that the model approach is a powerful tool for flotation cells diagnosis, operation and development of new control strategies, as well as, to evaluate the effect that de-sign and operating variables have upon the collection and froth zones performance in large flotation cells.

Jan 1, 2014

By Leroy E. Schulze

A review of development and a reevaluation of uses of the hydraulic air compressor are suggested by the constant changes in technology, which frequently make an old art valuable in solving current problems. Contacts with research workers in various branches of engineering indicate that this older method of producing compressed air may not be familiar to some or that its salient features might be useful in solving problems involving uses of compressed air. Briefly, a hydraulic air compressor may be described as an inverted siphon, consisting of an intake head where water and air are mingled, followed by a gravity-fall tube in which air is intimately mixed with the water and is compressed as the water pressure increases during the fall down the tube, then a separating, or stilling, chamber in which air bubbles rise to the surface of the water and collect in the upper portion of the chamber at a pressure equal to the weterhead maintained by the height of water in the discharge leg of the circuit. The water, which now contains only the fraction of air that has gone into solution, passes out of the separating chamber and rises up the discharge leg to the surface, which is, of course, at some suitable distance below the level of the intake. Present-day applications include (1) utilizing low hydraulic heads, which otherwise have little commercial values; (2) utilizing low hydraulic heads in reclamation work to supply compressed air, or in some instances to produce a small suction, for air-lift pumping (or for operation of air motors), with minimum attendance and without need for electric power; (3) utilizing medium heads, as at dam and lock installations, to produce compressed air for pneumatic operation of airlifts, gates, valves, and rubber gate seals; (4) utilizing underground waters, as in mines, to produce compressed air for general mine use; (5) using this method of isothermal compression of air in combination with standard compressors wherever hydraulic head is available, thereby securing the advantages of low-temperature intake to the mechanical compressors and reduction of moisture content below that of atmospheric air; (6) development of large air supply at pressures up to 150 p.s.i.g., which, after performing work in reciprocating or centrifugal expansion cylinders, is available at temperatures approximating -50° F. Possibilities in freezing and reheating should be mentioned which may prove economical for obtaining uniformly dry air for process work, wind-tunnel tests, or large air-conditioning installations, such as ventilation of underwater traffic tunnels, and may be economic for supply of supercharged air to gas-turbine plants.

Jan 1, 1954

By Harold J. Rose

The economic situation in Switzerland during recent years has resulted in theoretical studies , engineering development work , and many commercial installations of ingenious methods for using energy more efficiently . The purpose of the present investigation was to learn of recent Swiss developments for the more effective use of coal , which comprises 98.9 percent of the romaining known mineral - fuel reserves of the United States .

Jun 1, 1947

By The Staff

Development of the Eldorado Mine THE pitchblende-silver deposits of Great Bear lake, Northwest Territories, were discovered by Gilbert LaBine in 1930. The property owned by Eldorado Gold Mines, Limited, consists of 53 claims situated, for the most part, on LaBine point, on the northeast shore of the lake. The Company also holds a group of 10 claims on Dowdell point, 7 miles to the southeast of the main group and across Echo bay. The fractures traversing the ridge on LaBine point can be readily seen from the air. Lack of overburden and the scantiness of vegetation leave rock exposures which are visible for miles. The years 1931 and 1932 were spent largely in staking, prospecting, and examination of the outcrops. A small Diesel plant was shipped to the property in 1932 and underground operations were started. Entry was made into the ore-body by means of an adit. A 20-ton mill was completed in the winter of 1933-34, and since then operations have been continuous, except for temporary shut-downs for additions to the mill. TRANSPORTATION The mine is situated 28 miles south of the Arctic Circle and is reached by an air route of 1,140 miles from Edmonton. The water route follows the course of the Mackenzie River system from Waterways, Alberta, the end of steel, and is approximately 1,450 miles in length. Two portages, at Fort Smith and on the Bear river, respectively, are necessitated by the occurrence of fast water. Transportation was one of the major problems to be solved, and Eldorado Gold Mines, Limited, found it necessary to embark upon both water and air freighting on its own account. The Company now operates a Bellanca 'plane with a payload of 4,400 pounds, and a complete water transportation system. The latter was established some years ago by the Northern Transportation Company and it is still operated under that name, but the Company is now a subsidiary of Eldorado. Modern steel boats, oil tankers, and barges were added to the fleet this season. The greater part of the ore shipments are made by water, aircraft being used for this purpose only when occasion demands. Freight rates have been greatly reduced by direct ownership of carriers. For example, water-borne freight is now quoted 'to the mine at $ll0 per ton, as compared with $240 per tan four years ago.

Jan 1, 1938

By D Roughsedge, J van der Sandt, L van den Berg

Axial flow fans are commonly used as auxiliary fans in underground mines to supply air to development headings. As diesel dilution requirements increase the fans used in conjunction with ventilation bags are becoming larger in diameter to move greater quantities of air over greater development distances. It is not uncommon for mining operations to sometimes use a number of these larger auxiliary fans with high airflow capacity in parallel as primary fans for the operations. These primary fan stations are often considered temporary installations and the fan selection and fan station design is rarely optimised. These temporary installations may become permanent resulting in an inefficient or unreliable primary ventilation system. A recent study looked at the likely causes of multiple primary fan failures at one operation with axial fans installed as primary units where the fan selection and fan station aerodynamic design was far from optimal. This paper explores some of the typical mechanisms of failure such as high pressure stall, unbalanced airflow, and fan tip speed as well as fabrication material. The paper proposes a number of good practise principles that should be considered during the design of a fan station. A second topic covered is the advantages and disadvantages of using different types of fans such as axial, mixed flow and centrifugal units. Here the concept of fan specific speed and its relevance to fan selection is discussed. Finally the paper quantifies the effect of using a high pressure auxiliary fan as a primary fan in a low pressure circuit, which may increase the mineÆs operation cost.CITATION:van der Sandt, J, van den Berg, L and Roughsedge, D, 2013. Practical considerations when using auxiliary axial flow fans as a primary mine fan, in Proceedings The Australian Mine Ventilation Conference , pp 63-70 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013