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By C Young

The identification of Critical Risks, their associated Critical Controls, and the implementation of processes to ensure their ongoing management can be difficult and resource intensive. Answering the following Critical Risk Management related questions can be challenging: • What is a Critical Risk? • What is a Bow-tie Analysis and when should it be used? • What is Critical Control? • How is the effectiveness of a Critical Control assured, and how is this measured? • Who is responsible for managing Critical Controls? • What are the implications if a Critical Control is not effective? It appears that in the mining industry’s efforts to implement the Critical Control Management Process outlined by the International Council on Mining and Metals (ICMM), instead of embedding an integrated, well understood, value adding process, we have instead created a resource hungry monster that is poorly understood by numerous layers of the organisation.

May 5, 2022

By P. H. Jennings

Commercial tellurium commonly contains heavy basemetal impurities such as lead, copper, iron, etc., as well as selenium and oxygen. The base metals may be removed by vacuum distillation or by zone melting. Vacuum distillation is a convenient method for treating moderate quantities (~ 100 kg.) for the production of a material having a total content of heavy metals in the 10-30 ppm range. By zone melting, it is possible to lower all the heavy metal impurities tm below the limits of spectrographie detection. Neither vacuum distillation nor zone melting is effective for the removal of selenium, but treatment of molten tellurium with hydrogen converts selenium to hydrogen selenide. This procedure is too s low to be considered except as an adjunct to zone melting. In the course of air-melting, many of the more easily oxidized impurities form a dross and may thus be readily removed. Substantial refinement with respect to iron, tin, chromium, aluminum, sodium, silicon, magnesium, calcium and manganese can be achieved in this way. Although tellurium can be electrodeposited from either acid or alkaline solutions of the dioxide, various factors militate against successful electro-refining, amongst which may be mentioned the brittleness of cast tellurium anodes and the tendency for the metal to be deposited in dendritic form, even at low current densities.

Feb 1, 1966

The original JKMRC AG/SAG mill model was developed over 30 years ago and has been upgraded a number of times since then, with the current published version being the Variable Rates model that is now over 15 years old. Since this model was developed further enhancements have been derived, some of which are applied in-house and some which have yet to be incorporated. The published and the commercially available model in JKSimMet is currently undergoing a comprehensive overhaul with a vastly extended data base for model evolution and validation. Improvements developed within the AMIRA P9 project, in-house development and a number of collaborative projects, are being incorporated into the upgraded model structure. Enhanced capabilities will include: power-based breakage rates scaling; a far wider mill filling range (from 10% to 40%) that exhibits peak in throughput as mill filling increases; higher ball loads; improved pebble discharge function; improved slurry discharge function incorporating important mill design and operational influences; and the new size dependent breakage function. The model will also be able to accommodate some influence of liner design and multi-component ores (blends of hard and soft components). This upgrade is still a work in progress but substantial changes have been made to date. This paper presents some of the new improvements and their influence on the predictive capability of the model.

Jan 1, 2012

By J. N. Economopoulos

The mining industry is becoming increasingly aware of environmental issues and has made big forward steps in the field of environmental management. Legislation, social pressure and competition introduced changes in the industry?s policies and practices in order to conform to the new standards of environmental performance. The paper addresses the need for an integrated and systematic approach to the issues of environmental management within the mining industry.

Jan 1, 2002

By Andrew Hodge

ISSUES IN MINING LABOR The examination of mining labor issues is often confined to health, and safety. There are other issues, including the present state of mining manpower availability and utilization, and the nature of mineral industries' industrial relations, which are worthy of consideration. The state of the labor market for mining skills, the availability and utilization of mining engineers and related disciplines, the state of research and its employment of scientists and engineers, and the condition of mining industrial relations with all these groups, all have an important effect on the viability and economic health of the minerals production sector. PRODUCTION LABOR Why examine an industry's production labor market? People involved in an industry should be aware of what labor supplies will be relative to industry requirements. This advance information allows industry and government to plan ahead to alleviate problems by moving to affect labor supplies or to accommodate production to expected labor supplies. This is less costly and less painful than responding after the fact to labor market changes. Any industry requires some form of labor. Labor is especially important to the mining industry. Mining labor is well paid. Average annual earnings are higher than in manufacturing. Average hourly wages are also higher. Payroll costs form a high percentage of total cost in coal mining and nonmetallic minerals mining. In metal mining the percentage is comparable to the average for manufacturing. Payroll cost in oil and gas extraction is quite low, but a major proportion of cost is in the form of income to proprietors, i.e., unincorporated businesses. Mining labor is worthy of specific attention. The minerals extraction labor is unique in many ways. Mining labor and especially underground miners are differentiated from other "unskilled" labor. Miners cannot be considered as part of a larger labor pool. The mining labor market has exhibited a unique combination of characteristics. Mining is the only large sector of United States employment in which hourly wages are high and continuing to rise, yet employment declines. Although industry has introduced new labor-saving investments, and labor requirements continue to decline, there is evidence of a mining labor shortage. Specific problems have arisen in the mining labor market such as a present labor shortage in nonfuels mining. Understanding the causes and remedies for these specific problems is also important. These various problems and questions may be handled in a unified manner by examining the relationships of certain economic variables. The relationship that exists between changes in output, employment, labor productivity, and hours worked per week may be stated explicitly:

Jan 1, 1976

By D. T. Farnham

The shale used at the Renton plant of the Denny-Renton Clay and Coal Co. for the manufacture of vitrified paving brick occurs in a hill rising from 200 to 300 ft. above the level of the valley in which the plant is situated.

Jan 1, 1915

By John Harmon

THIS paper was written-with two objects in view: (1) To describe in detail what has been done toward the ventilation of the main unit of the Portovelo mines and the results; (2) to give information that may be useful to anyone who may have to make a preliminary mine ventilation survey, with recommendations for the improvement of the existing system and finally the maintenance of the improved system.

Jan 1, 1931

By W. F. McDermott

One of the major improvements in ore grinding economics in North America has been the introduction of autogenous grinding. The history of this has been well documented in previous AIME presentations and in the literature. Pickands Mather & Co. has been very active in the development of autogenous grinding since 1957. This early work led to the application of autogenous grinding to the Wabush Mines ore in 1965, with the installation of 6-24 ft. diameter by 8 ft. long - 1,750 HP mills. Development work recently completed in 1971 on another ore has led to the decision to install 5-36 ft. diameter by 15 ft. long - 12,000 HP mills when this project goes ahead. Between these two decisions lies a tremendous amount of research, development, and application of autogenous grinding to a variety of ores. The Pickands Mather Metallurgical and Research Laboratory in Hibbing, Minnesota has tested, in its pilot plant facility, ores from 9 different deposits. Some of these deposits have as much difference within their own ore types as there is between the various deposits. Therefore, it is safe to say that over 20 different ore types have been tested and flowsheets developed for commercial applications. Of the 9 projects, 3 are in operation. These are Wabush Mines in Labrador, Canada, (1) Savage River Mines in Tasmania, (2) and The Griffith Mine in Red Lake, Ontario, Canada. (3) Pilot plant work has encompassed over 300 individual tests. These tests were carried out in mills that were 5-1/2, 8, and 12 ft. in diameter. Grinding power requirements for the primary autogenous milling has varied from 2 to 30 KWH/Lt of crude ore.

Jan 1, 1972

By Ruddle R. W.

The slags produced in copper smelting are largely composed of silica and ferrous oxide and may therefore be regarded as essentially ferrous silicates. A fair amount of information is available on the constitutions of the liquid slags used in copper smelting and, in this connection, the large volume of work being carried out on steelmaking slags should be helpful. Constitutional diagrams are available for most of the principal systems involved (SiO2-FeO; SiO2-FeO-Al2O 3; SiO2-FeO-CaO; SiO2-FeO- MgO; and SiO2-FeO-CaO-Al2O3) and these show that additions of Al2O3 and CaO reduce the freezing points of SiO2-FeO slags but that additions of MgO increase the freezing point. A certain amount of information is available on the thermodynamics of slags, but much further work on this subject is required. Modern theories of the constitution of liquid slags deny the existence of molecular compounds but consider that liquid slags are mixtures of various ions such as, Fe2+. O2- and SiO4(4-). Little appears to be known of the reactions between matte and minor constituents dissolved in the slag

Jan 1, 1953

By G. J. Hamilton

"THE Royalite-Canada Southern Coleville No. 1 gas strike of August 15th, 1951, and the closely following low gravity black-oil strike of August 23rd, were the first of a series of recent oil and gas discoveries in western Saskatchewan. They are in what is now known as the Coleville field, 25 miles north and west of Kindersley and 30 miles east of the Alberta-Saskatchewan border (Figure 1).Gas flows have been recorded in the Viking sand at daily rates of between 5 and 10 million cubic feet, and black oil of 15° A.P.I. gravity is produced from Mississippian sediments of Banff age at a daily rate .of 50 to 100 barrels on pump.Development drilling was carried on during the winter months, with very little attempt at step-out exploratory ventures. This year, however, a step-out programme to the northeast (Figure 2) is •being carried on in order to determine the position of a possible truncation of Mississippian sediments in that direction. Section 30 of the Coleville area has been fully developed on a 20-acre wellsite basis, and structural information is restricted to local rather than regional interpretation. No attempt will be made in this paper to interpret the Coleville area with respect to the regional geology in any but a general manner."

Jan 1, 1952

By Norman B. Davis

THE ceramic group of industries is comprised of those engaged in the manufacture of cement, glass, artificial abrasives, whiteware, including earthenware, stoneware, porcelain tableware, porcelain sanitary ware, electrical porcelain, floor and wall tile, porcelain enamel on metals, refractories of all kinds, sewer-pipe and structural clay products, such as terra cotta, brick, and hollow tile. The various sub-divisions of the industry produce a wide range of articles on which we depend for our creature comforts from day to day, perhaps to a greater extent than we generally realize. The industry, in turn, depends on a great number of minerals, and chemical products derived from minerals, and it is the object of this brief paper to present a list of these with notes indicating the particular applications. In order to bring home the importance of the industry to your daily life, stop and consider the many things around you accepted as a matter of course. Cement provides the smooth surfaces of many of our highways, city streets, and sidewalks. It enters into nearly all types of construction, alone or in combination with other clay products. Glass we hardly appreciate because we can see through it so easily, but it is there to serve us in windows, doors, and other light-transmitting structures. Glass is the universal means of transporting liquids and beverages, our beverages are usually served in it, and, with the recent development in fine spun glass textiles, there is a possibility of glass clothing in the future. Chinaware, a general term for table dishes, may be earthenware (not vitrified), semi-porcelain, or bone china, but it is before us three or more times a day ?and we seldom think of the minerals that have made these products possible. Floor tile, wall tile, and other ceramic specialties for interior and exterior use and decoration please the eye and provide sanitary surroundings.

Jan 1, 1938

By W. L. Sherwood

Present conventional techniques for primary steelmaking in both integrated and non-integrated plants are outlined. 'Direct reduction' alternatives are reviewed and categorized according to the nature of the product produced, with particular emphasis on the limited number designed to yield steel as the end product. A proposed new technique, referred to as the Sherwood Process, is described in some detail as a new combination of selected features from the prior technology. This process is in-tended to realize, in integrated operations, the result of continuons steelmaking directly from the ore in a single plant and, in non-integrated operations, continuons steel-making from a metallic charge of scrap, sponge iron or pig iron. Prominent features are continuons processing in elongated, horizontal, rotary furnace equipment, controlled direct heating of each process stage and, for the over-all integrated process, a size separation for removal of excess solid reductant and other waste just prior to the melting step. Material and energy balances are presented as well as exemplary cost data. Reasons for selecting this particular combination of process elements are dis-cussed.

Jan 1, 1968

By Neil McMillan

"By any measure of common practice, Claude Resources' Seabee Gold Mine in Northern Saskatchewan should not now be operating. Not because reserves dwindled, or grade dropped or prices weakened or technical problems arose, but because a host of unimaginable other problems beset the project, any one of which would normally have led to the mine's failure.The success of the Seabee Mine, and it is extremely successful, is a story of the vision and blunt determination of two men. Neither is remarkable in his own right but each possesses the characteristics which were necessary to forge a highly productive and profitable narrow-vein mine in the midst of the most bizarre and unpredictable events which likely have ever beset a mine start-up in Canadian history.Together, Bill MacNeill, a Saskatchewan born, former bush pilot and Ray Gagnon, a big hearted, hard-fisted, miner with 44 years of experience in Canada's underground, built the Seabee Mine.They didn't accomplish this with brilliant geology, outstanding engineering or nimble corporate manouvering but rather a stubbornness and raw common sense which likely are all too often, ingredients missing in failed projects.The Seabee Mine is 100% owned by Claude Resources, a Saskatoon based company taken over by Bill MacNeill, its current chairman, in 1982. The company is listed on the TSE and produces 1200 barrels of oil per day and about 60,000 oz of gold per year. The company has a strong balance sheet, is very profitable and has 18 million shares outstanding.The Seabee property in Northern Saskatchewan started out like many other gold exploration properties in Canada.It was discovered in the l 940's by what is now Cominco, and, while highly regarded by that company the property sat largely dormant until acquired by Claude Resources in 1985.Claude did what most junior exploration companies would do and went looking for a company with a depth of expertise to joint venture the property.That company was Placer Development who could earn a 55% interest in the Seabee by delivering a bankable feasibility study on the Project by July 1988 and providing financing to production.Placer Development was an excellent company and spent over $8 million dollars on the Seabee over a 3 year period. Unfortunately for Claude Resources, Placer Development merged with Dorne Mines in 1987 and the new merged company, Placer Dome, established a minimum production threshold greater than the 50,000 oz per year which the Seabee appeared capable of supporting at that time. Placer Dome's request for an indefinite extension of the joint venture agreement to allow it to drill off a larger ore body was rejected by Claude Resources and the Seabee Property was returned to Claude in 1988."

Jan 1, 1998

By J. Spotts McDowell

J. W. RICHARDS, So. Bethlehem, Pa.-The paper is certainly an exceedingly, valuable one and it gives detailed information which should be utilized in the following way. There are probably twenty different circumstances or conditions under which silica bricks are used. Sometimes they are used under high pressure, at others under low pressure, at times for low temperatures and others for very high temperatures. If the methods of this paper are followed out, and if the precise mechanical and thermal properties are determined and can be reproduced, the industry can furnish the proper brick for any particular purpose. There is at present only an imperfect classification made as to properties and uses, but we need a "much more scientific classification of the uses to which the bricks are to be put and then should manufacture the bricks suited particularly for each of those purposes. There is one property which is not mentioned in the paper and which is of considerable importance, that is, the 'electrical conductivity. There may be other properties besides, which a good research laboratory can determine, and when we have listed all the various properties and noted the way in which they can be reproduced, the maker can then specify his exact requirements and the corresponding quality of brick can he selected or made to meet them. H. D. HIBBARD, Plainfield, N. J.-About a year ago I had some experience in another country, in melting steel, where silica bricks made in that country failed, but in a different way from those in America. Here, when the bricks get too hot, they are partly melted and string down

Jan 4, 1917

By Thomas S. Blair

I FEEL a certain sense of responsibility in bringing before you the subject of the direct process in iron manufacture. I am aware that, in such a body as I have now the honor of addressing, there are few who are not already so well informed upon its past history that it would be a weariness to them to listen to anything else than an account of practical success. Yet, to claim that success involves so much that, if I do not make good my claim, I deservedly expose myself to severe criticism. The whole literature of the art, so far as it relates to the direct process, is, up to this time, but a history of failure. It is safe to say that more money, time, and talent have been fruitlessly spent in the pursuit of this object than in all the other unsuccessful efforts in the whole line of iron metallurgy. A distinguished authority in patent law has remarked that " the invention records of the United States and of foreign countries are filled with the waifs and abandoned relics of these abortive struggles." Dr. Percy, whose great work may be taken as an epitome of all that was worth mention, whether useful or curious, in pig-iron metallurgy, up to the date of its publication (1864), after giving elaborate accounts of various attempts at the direct process, condenses his own opinion of all that had been then effected, into a brief but summary comment upon a pamphlet of one of the sanguine inventors who had said: "It is evident that the present mode of working iron

Jan 1, 1874

Following the experimental work of Denny, Robson, and Irwin, and the clinical investigation by Crombie and Blaisdell, an investigation of aluminium therapy was begun at Washington, Pa., which is situated In a very large industrial section of the State. Some of the men to be studied were from plants manufacturing silica brick, refractories used in steel and glass manufacturing, and semi-porcelain table-ware; others were workers in foundries, sand blasters, and men engaged in the quarrying of ganister rock.This group of workmen gave an opportunity to study the effects of aluminium on various types of silicosis which differed somewhat from that found in hard-rock miners.EXPOSUREIn their occupations, the men studied were exposed to silica dust concentrations ranging from 17 to 97 per cent free silica. In the silica brick industries, the unfired product averages 96 per cent silica in the form of quartz, whereas the fired brick contains 50 to 62 per cent. cristobalite plus 11 to 80 per cent. tridymite, forms of silica that, on account of their higher solubility, are more toxic than quartz. The operational dust counts in the plants varied from 15 to 9,500 particles per c.c., and the median particle size from the aerial samples was 1.0 micron for the green product and 2.0 microns for the fired product. The length of exposure varied with the occupation as well as with the individual plant, but disabling silicosis could be produced in less than four years in certain exposures. The average time needed to produce radiological silicosis in those susceptible to this disease was eight years. Some of the men in our series of cases have been treated as long as fifteen years after exposure had ceased, and have improved under treatment.The dust counts mentioned above had been reduced prior to the aluminium therapy studies and the presen.t exposures do not exceed '900 particles per c.c., the average being 370 particles. per c.c. This improvement in dust conditions was due to improved dust control apparatus, which was installed before aluminium therapy was instituted. Aluminium powder is not a substitute for dust control.PATHOLOGYThe pathological picture of silicosis in men engaged in the ceramic industry is somewhat different from that in hard rock miners." Due to exposure to high concentrations of dust containing high percentages of silica of varying degrees of solubility andvery small particle size, these men are subject to a relatively rapid type of silicosis, which sets up an acute...

Jan 1, 1945

By K. A. Clark

"The repacked mineral aggregates of good grade oil sands have permeabilities ranging between 15 darcys to 350 millidarcys. The variation is due to the silt contents of the aggregates. Few good grade oil sands contain as much as 30 per cent •silt, most of them contain less than 20 per cent, and a large proportion have less than 10 per cent.The permeabilities of repacked good grade oil sands (oil included) depend on the degree of liquid saturation. When saturation with oil plus water reaches between 80-90 per cent, permeability is reduced to zero. As total saturation decreases below 80 per cent, permeability increases ranidly. Permeabilities of between one and two darcys were observed for total saturations between 60-70 per cent.The mean value for 18 measurements of the permeabilities of ""undisturbed"" core samples of good grade oil sands was 50 millidarcys. This value is •probably too high. The mean value for 20 measurements on core samples of interbedded oil sand and shale was 100 millidarcys. The mean value for 11 measurements on shale was 10 millidarcys."

Jan 1, 1960

By C. M. Romanowitz, H. A. Sawin

PLACER dredging as we know it today, especially gold dredging, is an industry about 40 years old, dating from the beginning of this century, when a few mining men in California saw the possibilities in adapting earlier dredging methods to California placer fields in and immediately adjacent to streams. At first it was thought that dredges must be operated in existing stream beds, but experience soon pointed the way to dredging alluvial deposits of old stream beds, operating on landlocked dredging ponds. Within the first five or six years of modern dredging, experience was gained so rapidly that dredges to dig 60 ft. below water level were designed and built. This depth was believed by many operators to be the maximum at which successful dredging could be carried on. Alluvial deposits of gold, suitable for dredging, were readily handled by equipment available and developed early in the industry's history. Much of the gravel was easily dug and if deposits were cemented, contained large boulders, or for some other reason could not be handled by a dredge, the ground was abandoned in favor of other deposits that could be handled easily. Many failures, adversely affecting the dredging industry, resulted from attempts at that time to extend the scope of placer dredging with equipment not suited to the formation being dredged. Dredging ground suited to early equipment was exhausted eventually, but many supposedly undredgeable alluvial fields containing gold in commercial quantities were found and became known to dredgemen. Improved equipment was needed to work deposits known to exist at great depths or associated with unusual obstructions. Operating companies looked to dredge manufacturers and metallurgists, particularly manganese-steel foundries, for improved designs and materials. Experience developed in California has spread throughout the world, and dredges of improved types have been adapted to the mining of platinum and tin as well as gold. Space will not permit a description of all the improvements in dredging since the early days, but a few of the recent developments are worthy of note, because they make possible the dredging of placer deposits of great depth, those having hard, irregular bedrock or containing large boulders in great quantities, and compacted or cemented gravel deposits. DEEP DREDGING At Hammonton, Calif., Yuba Consolidated Gold Fields has, within the past two years, built its dredge No. 20. The company has operated continuously in that field since 1904, digging successively at maximum depths of 60 ft., 80 ft., 112 ft., and now 124 ft. below water level. The first dredges were equipped with buckets of 6 and 7 1/2-cu. ft. capacity; six dredges operating in the field today have 18-cu. ft. buckets, digging now 65 to 124 ft. below water level. Some ground near Hammonton has been dug for the third time, owing to the devel-

Jan 1, 1941

By Olin M. Hart

Uranium ores occur in the Lower Cretaceous Inyan Kara group of heterogeneously stratified fluvial and fluvial-marine sandstones in the Black Hills of western South Dakota and northeastern Wyoming. There are three principal mining districts, each in the ancestral and present drainage area of a major river partially responsible for stripping the region to its present topographic form. Primary minerals in the deposits are coffinite and uraninite with minor amounts of paramontroseite and haggite. The ore minerals coat sand grains and fill interstices of complexly cross-stratified sandstone along solution fronts similar to "roll" type deposits of the other districts. Minerals of oxidized deposits are typically carnotite and tyuyamunite with different proportions of secondary vanadium accessory minerals. Ground water was the transporting medium and deposition of primary uranium and vanadium minerals occurred in reducing environments produced and controlled by physio-chemical characteristics of the sedimentary rocks.

Jan 1, 1968

By Richard L. Gordon, Charles J. Johnson

Electric power demand doubles about every ten years, and because of the associated burgeoning fuel requirements, power stations absorb over half of the coal output in the United States. Throughout the 1960's, demand for coal utilized to generate electricity grew at an average annual rate of 6.5% but coal producers held back greater expansion because they expected nuclear plants to proliferate faster than they actually did. Even so, the growth rate is expected to continue at the 1960's rate until at least 1976. The continuation of the 6.5% growth rate beyond 1976, however, will require additional orders for coal-fired plants during the early 1970's. In fact, plants consuming a total of 130 million tons of coal must be ordered in the next few years. If the requisite plants materialize, total 1980 coal output for electrical power generation will be approximately 600 million tons.

Jan 1, 1971