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"The North Star and Don Jon copper deposits lie beneath the waters of Thompson Lake, which is 12 miles east of Flin Flon, Manitoba. The deposits were discovered during the years 1949 and 1951 by diamond drilling done in the vicinity of pyritic showings on the shores of two small islands in the lake. The Don Jon ore body lies 1, 700 feet southeast of the North Star orebody and is connected with the North Star mine workings by a crosscut on the 600-foot level (Figure 1 ).Production began on January 1, 1955, at a combined rate of 200 tons per day. The ore is trucked, on 24 miles of highway, to the Hudson Bay Mining and Smelting Co., Limited mill at Flin Flon.Regional GeologyRocks in the Thompson Lake area are Precambrian volcanics, ranging in composition from andesite to rhyolite, with related tuffs and breccia. These rocks have a general north-south trend and are steeply dipping. The area is part of the Lac Aimee fault block, which probably is the southward extension of a south-plunging syncline now thrust some miles to the north. This regional deformation has produced many subsidiary zones of intense shearing and crumpling. It is in two of these zones of shearing and drag-folding that the orebodies occur. The only recognizable intrusive is a narrow diorite sill which trends northeasterly near the west shore of Thompson Lake.The North Star MineA pyritic showing, carrying some chalcopyrite, was discovered around the year 1930 on the west side of a small island near the west shore of Thompson Lake. This ground was included in a group of claims acquired by the Hudson Bay Exploration and Development Co., Limited in 1947.In the years 1949 to 1951, a diamond drilling program outlined a copper sulphide orebody. This ore zone comes to surface beneath the lake, about 300 feet north of the pyritic showing on the island."

Jan 1, 1949

By William Gleason

"Mining roots run deep in Glenrock, WY, a town that was founded in part, because of the coal mining that began in the late 1800s. But that rich history also now threatens large parts of the town that were built over the top of the mines. Like many towns in the Western United States, mining is a proud part of the historical fabric and heritage of the town, but the legacy issues from past mining activities continue to present challenges to modern-day engineers.In the case of Glenrock, a small town about 40 km (25 miles) east of Casper, it is flooding from a century of water that has accumulated in the down geologic dip of the furthest northeastern extent of 87 ha (217 acres) of mine workings that has made the town susceptible to sinkholes and other issues (Fig. 1).Full commercial coal mining production began in Glenrock in 1887 during the development of the Fremont, Elkhorn and Missouri Valley railway. Due to poor overlying roof rock and continuous flooding within Glenrock, Mines No. 1 and 2 were fully closed in 1909. During its history, an estimated 87 ha (217 acres) were mined with 50 to 60 percent extraction ratio within the eastern town limits through room-and-pillar mining. It is estimated that the mines produced 22 kt/a (25,000 stpy) during their lifetime. A century later, the water pressure built up in the northeastern most portion of the mine has created serious concerns for residents.In 2016, the Wyoming Department of Environmental Quality’s Abandoned Mine Lands Divisions (AML) investigated a number of subsidence events in the town including sinkholes following heavy precipitation. The AML investigations confirmed that most events were related to the previous mining in the area.Mitigation efforts on the mines were done in the 1980s and 1990s, but the problems in the town and in a nearby subdivision persisted, leading the AML to search for alternative solutions."

Nov 1, 2019

By AIME AIME

The XCVIIth meeting of the Institute for the reading and discussion of papers will be held at Spokane, Wash., beginning Monday, Sept. 27, 1909, as already announced in Special Circulars of May 8 and Aug. 14, 1909, and in the Bulletins for June, July, and August. The meeting will be preceded by a tour through Yellow stone Park and visits to Butte and Anaconda, and will be followed by visits to the Coeur d'Alene district, to the Alaska-Yukon-Pacific Exposition at Seattle, to the mining- and smelting-plants near Salt Lake, and to the iron- and lead- and zinc-plants at Pueblo. The special train for the party' will leave Chicago, September 16, and return about October 12. Details of the itinerary are given later in this announcement. The Secretary of the Spokane Local Committee is Lyndon K. Armstrong, 615 Hyde Block, Spokane, Wash., to whom should be addressed all inquiries concerning local matters. The control of the papers and proceedings will remain in charge of the Institute office, as usual. It is greatly to be desired, both in behalf of the Institute and in recognition of the many courtesies to be extended on the trip, that the excursion party be made larger. Exceptional facilities to visit the many mines and smelters have been freely provided; and members are requested to make all reasonable effort to attend the meeting at Spokane and participate in the excursions. For those who cannot join in the entire trip, it may be possible to provide special Pullman accommodations after leaving Yellowstone Park. In order to make the necessary arrangement, however, the names of members and guests contemplating this partial trip should be sent at once to Theodore Dwight, 29 West 39th Street, New York City. The general cost of the trip per member will be $300, which includes transportation, berth, and meals for the entire trip from

Sep 1, 1909

By G. Vibert Douglas

It has long been recognized that there are considerable difficulties connected with the physical and chemical explanation of shoots of ore. The literature of Mining Geology has frequent references to this subject; but the reasons given for the actual location of primary ore-shoots have been very tentative. In practice, the geologist or miner depends to a great extent on sampling and assaying to determine the boundaries of profitable ore within the mineralized zone. An ore-shoot is a portion of a mineralized zone which has a sufficient concentration of valuable minerals to make it ore. Ore deposits have been classified according to many schemes. There are classifications based on morphology and on genesis. However, it is also possible to classify hypo-gene hydrothermal ore-bodies in terms of ore-shoots or vice versa. A.-Ore-deposits in which the whole of the mineralized zone is ore, which is the same as saying that the ore-shoot extends throughout the mineralized zone. An example of this type of deposit would be the pyritic mineralization of Rio Tinto. B.-The second type would comprise those deposits in which the ore-shoots bear some relation to the geological structure of the area: all deposits in which 'bonanzas' occur in folds in the zone, at the intersection of veins along certain fault (or joint) features and other such controls. There are a great many examples of this type: (a) The Rhodesian copper lodes, where Bancroft and Gray have pointed out the association of the shoots of ore with drag folds. (b) A similar association has been pointed out by Faribault for some of the gold veins of Nova Scotia, e.g., Mount Uniacke. (c) The great bonanza of the Comstock lode in Nevada. C.-Deposits in which the localization of ore has been effected by the chemical character of the wall-rock. Examples of this type are the Fahlbands of Scandinavia, and the 'indicator' deposits of Ballarat, Australia. D.-Lastly, deposits in which there is apparently no structural and no chemical control.

Jan 1, 1934

By P. C. Santos-Munguía, F. Nava-Alonso, O. Alonso-González

"The gold recovery of a Mexican cyanidation plant, in Sonora, has been decreasing due to the increasing presence of gold tellurides. This work presents the results of different processes aimed to recover the remaining gold from the cyanidation tailings of the operation. The cyanidation in the mine is performed at 0.1 g/L NaCN and pH = 10.3, adjusted with lime. The treatments studied in the laboratory with these tailings were: cyanidation at higher cyanide concentration than that used in the plant, cyanidation with oxygen injection, cyanidation with oxygen and lead nitrate addition, and thiourea leaching. The results obtained with each of these treatments are presented and discussed with the final objective of proposing a method to recover the gold associated with tellurium.INTRODUCTION It has been demonstrated that gold telluride is refractory to the conventional cyanidation process and, for this reason, some alternative methods to recover precious metals from tellurides have been proposed. (Zhang et al., 2010). These include cyanidation with modified conditions or the use of non-cyanide leaching agents. This work presents the gold leaching results of tests performed with a sample of cyanidation tailings obtained from a Mexican deposit containing telluride species. The mine exploits a mesothermal deposit with a molar Te/Au ratio of 1, containing also lead, molybdenum, bismuth and tungsten. Gold is recovered from the ore by standard cyanidation, however, lately the gold recovery has decreased, likely due to the tellurium content of the ore. The sample used in this work was the cyanidation tailings of this deposit. It was treated in the plant by cyanide heap leaching (0.1 g/L NaCN, pH = 10.3 adjusted with lime). Some gold remained after the cyanidation and it was thought that this gold was associated with tellurium. The objective of this work was the recovery of the remaining gold from the tailings by an alternative process."

Jan 1, 2017

By Robert E. McIvor

"The design/optimization of the pump and cyclones to maximize grinding circuit efficiency first requires a concise understanding of, and clearly defined specifications for, desired grinding circuit performance. Subsequently, the pump and cyclone performances that provide the desired grinding circuit performance can be defined. Once the performance requirements of each process unit are determined, selection of physical equipment parameters that will deliver those performances can be carried out.The Functional Performance Equation shows that there are two distinct efficiencies in closed circuit ball milling. One of these, “Circuit Classification System Efficiency” (CSE), is the fraction of “coarse” material inside the ball mill upon which grinding energy is deliberately expended, versus the remaining fraction of “fines” or finished size material inside the mill, upon which grinding energy is wasted (on over-grinding). The role of the pump and cyclones is to maximize CSE, which is the desired grinding circuit performance. The obtainable target CSE for any given circuit can be estimated, for example, by referring to a plant data base of CSE’s. Design/optimization guidelines then allow us to specify the pump and cyclone performances that will achieve the target CSE.This paper outlines the step-by-step, systematic method of pump and cyclone selection which maximizes CSE. Numerous examples of its successful application are provided.THE FUNCTIONAL PERFORMANCE EQUATIONObservation of the feed and product size distributions going into and discharging from the mill in grinding circuits with low versus high circulating load ratios initially led to the definition of “Circuit Classification System Efficiency” (or CSE, McIvor, 1988a), and subsequently the discovery of the Functional Performance Equation (McIvor, 1988b; McIvor et al, 1992). The CSE is the fraction or percentage of “coarse” (usually in reference to the plus P80) size material inside the mill, versus “fines” or product size material finer than the circuit P80. It can be readily calculated by taking the average of the percentage of said coarse material in the mill feed and mill discharge streams. As this also represents the percentage of the mill energy expended on targeted, coarse size material, it is directly proportional to overall grinding circuit efficiency and production rate. This is all clearly expressed in the Functional Performance Equation for ball milling circuits, for which the derivation has often been presented (e.g. McIvor, 2006)."

Jan 1, 2011

By Y. E. Brylyakov, M. A. Kostrova

"The apatite staffelite ores (ASO) of Kovdor deposit are dominated by fine-grained aggregates containing both phosphate minerals and silicates — vermiculite, smectites, zeolites. These minerals exhibit ion-exchange properties. In this connection, the magnitude of cation exchange, along with the content of P2O5 and CO2, is an important property of apatite staffelite ore, which largely determines the performance of concentration processes. In the examined ASO samples, the magnitude of cation exchange measured in terms of Ca2+ is 2546-4790 g/ton. The conducted laboratory studies of apatite staffelite ores with various mineral composition showed that adding calcined soda improves the recovery of P2O5 into the flotation concentrate. Full-scale tests were conducted at the apatite staffelite ore processing plant at Kovdor Mining and Concentration Operation and demonstrated the high performance of the proposed agent treatment. The test results showed that in the flotation of apatite staffelite ores, the optimum calcined soda feed rates range from 3,500 to 5,000 g/ton of the flotation feed. With close flotation feed and concentrate grade parameters, the P2O5 recovery gain is 17%. The effect of adding soda is associated with the desorption of the hardness cations from the minerals, precipitation in the pulp and, accordingly, improvement in the ionic composition of the liquid phase of the flotation feed due to a reduced content of calcium ions. Based on the test results, the proposed agent treatment with an elevated feed rate of calcined soda was implemented at Kovdor Mining and Concentration Operation in the flotation of apatite staffelite ore. The apatite staffelite ores (ASO) of Kovdor deposit are dominated by fine-grained aggregates containing both phosphate minerals and silicates — vermiculite, smectites, zeolites. These minerals exhibit ion-exchange properties. These minerals have certain properties requiring a more detailed examination for a better understanding of the flotation properties of apatite staffelite ores."

Jan 1, 2018

By Victor Dolmage

"The localization of orebodies by geological structures is well demonstrated at the Copper Mountain mine of southwestern British Columbia. These extensive deposits; owned and workd by the Granby Consolidated Mining; Smelting and Power Company; are at Princeton; abo!lt 150 miles east of Vancouver and 40 miles north of the International boundary. The geology of the deposits and the surrounding district is described by the present writer in Memoir 171 of the Geological Survey of Canada; pub1ished in 1934.The main geological feature is a gabbro stock, elliptical in plan, with a major axis about 5 miles in length extending in a northwest-southeast direction. The stock varies in composition from syeno-gabbro (gabbro plus orthoclase) through diorite and syenite to a core of syenite pegmatite. All the members contain orthoclase, which ·increases greatly in amount toward the centre, but all are devoid of quartz. The stock has been injected into a steeply folded series of volcanic flows, breccias, and tuffs that strike more or less parallel with the major axis of the stock. On its northeast side the stock is flanked by a band of fairly coarse volcanic breccia of andesitic composition and ·having fragments up to several inches in length. Where this breccia is tangential to the stock it is both dynamically and chemically metamorphosed to a marked degree, and within the zone of this metamorphism are enclosed the copper deposit~. The ore consists of bornite, chalcopyrite, and a little magnetite occurring as disseminated grains and small veinlets in the metamorphosed breccias. The only gangue minerals are orthoclase, albite, oligoclase, and biotite. The two most common vein minerals, quartz and pyrite, are conspicuously rare or absent. The dynamic metamorphism has produced two well-defined structures, namely, a strong schistosity parallel with the curved vertical contact of the stock and a very striking set of small, straight, nearly parallel open fractures that stand nearly vertical and at right angles to both the schistosity and the stock contact. These are called the ore fractures."

Jan 1, 1954

By Flavio Rojos-Tapia, Oscar Pereira-Cerda, Samuel Sánchez-Pino, Samuel Sánchez-Baquedano

"Pneumatic flotation was introduced to the Chilean Copper Mining Industry in 1993 by Ingeniería de Minerales S.A. (IDM). The technology is based on the designs of Dr. Rainer Imhof from Germany, who is the designer of several different types of pneumatic flotation cells, already sold through his Company Maelgwyn Mineral Service Limited (MMH). The company is represented by Ingenieria de Minerales S.A. (IDM) in South America.Pneumatic flotation, has been used in tough industrial applications .It has been successfully used for metallic ores such as copper sulphide and oxide minerals, copper slag, silica and silicates from iron magnetic preconcentrate (reverse flotation) and gold. It has also provided promising results when applied to molybdenum flotation. The latest applications, with ultrafine molybdenum particles in operating plants, is showing the V and G Cell (end model designed) as a real technological alternative to conventional flotation., The G Cell is an extremely high speed flotation machine with high selectivity which introduces the possibility of producing a final molybdenum concentrate with only one stage of cleaning. This is a completely new development in molybdenum flotation in the industrial circuit which has the potential to dramatically reduce the circulating load in the cleaning circuit. As a consequence the capital costs of future Molybdenum plants may also be reduced. The suitability of the G Cell will have to be determined on a case by case basis but it provides the metallurgist with an alternate flowsheet for consideration.The good performance of the G Cell can be explained by the high gas hold-up and very effective micro-turbulence which helps improve the attachment of solid particles to the bubbles. This technology may change our traditional concept of residence time in flotation. Additionally, the rotation phenomena introduced in the vessel of the G Cell ,creates radial separation forces which are critical to achieving a more rapid separation of the target minerals from the tailing. This results in a much reduced residence time requirement in the flotation machine. Some benefits associated with the use of the new G Cell are: less energy consumption, less maintenance costs, simple and reliable circuit to operate and a small area required for installing the circuits.As a result of the industrial experience in the Chile, the pneumatic flotation type G Cell can be regarded as a technology which must be considered as a replacement technology for the rougher and cleaner stages for fine particle flotation."

Jan 1, 2008

By Charles H. White

Discussion of the paper of A. L. Sweetser, Tress., xxxviii., 236. CHARLES H. WHITE, Harvard University, Cambridge, Mass. (communication to the Secretary*) :-Those interested in leaching-processes gladly welcome contributions on either laboratory-tests, such as are reported by Mr. Sweetser, or mill-tests made on larger quantities of ore; and especially valuable are such reports, even with negative results, if the methods adopted are the outgrowth of an intimate knowledge of the conditions to be met. It seems very desirable, therefore, that as complete details as possible be given in reporting on such tests, particularly with respect to the character of the ore under examination. The questions of prime importance in the sampling of ore and in the making up of charges for laboratory-tests are those respecting its grade and uniformity. In Mr. Sweetser's paper the first of these questions is answered definitely, but the answer to the second, although apparent on inspection of the results, might be more strongly emphasized with advantage, since it is only on account of the extreme uniformity of the ore that the satisfactory results obtained could have been expected. It seems advisable to call attention to the fact that for average ores, and more particularly for uneven, or 11 spotted ores, the quantities used by Mr. Sweetser are not usually regarded as sufficient to insure satisfactory results. Let us examine the method somewhat in detail. The ore was crushed to pass a 5-mesh screen, and a sample of 45 lb. was taken out for assay and tests. The diameter of the largest grain of this ore, according to Richards,1 was 2.67 mm.-assuming here, as in the following cases, that the wire of the screen was of the largest size used for the purpose, thereby giving any possible advantage in this respect in favor of the method. The table in Richards's book, p. 852, shows that 45 lb. is a sufficient quantity for a fair sample with uniform ores, but not sufficient

Jan 7, 1908

By W. J. Farley

"The Sherritt Gordon mine is 100 miles north of The Pas in northern Manitoba. Copper-zinc ore was discovered on the property in 1922. Production began in 1931 and continued to June, 1932, when operations were suspended because of the low price of copper. Operations were resumed on August 1st, 1937, and have been carried on continuously from that time to the present (March 1947). The production of metals up to the end of 1945 was copper, 287,129,880 lb.; zinc concentrate (50 per cent) 104,419 tons ; gold, 79,388 oz.; silver, 2,529,974 oz.GENERALThe ore occurs in two deposits, the east and the west. Both are enclosed in gneisses that are highly metamorphosed sedimentary and volcanic derivatives. The rock beneath the deposits, and hence forming their footwall, is gneissoid quartzite; the hanging-wall rock is basic garnetiferous hornblende gneiss. Pegmatite commonly occurs along both foot- and hangingwall peripheries and as isolated blocks and fragments within the ore zone . These blocks and fragments are considered to be residuals of unreplaced host rock .The ore is relatively coarse grained and ranges from the massive to the disseminated type. The metallic sulphides composing these, named in the order of their abundance, are pyrite and pyrrhotite ( 2-1 ratio) , chalcopyrite, sphalerite (marmatite) , and minor chalmeriite; subordinate amounts of gold and silver are recovered . The insoluble content of the ore averages about 35 per cent.Another deposit known as the Bob Lake, much smaller and lower in grade but having very similar relationships, occurs about 3 ½ miles to the northeast of the main Sherritt Gordon ore masses.STRUCTUREThe Sherritt Gordon orebodies are of the replacement type, and lie within a pegmatite sill that has been intruded along a contact between quartzite and hornblende gneiss. The two main orebodies are intimately related, for the east deposit is an erosional remnant of the lower, easterly limit of an orebody once continuous with the west body. The ore lies along the southwest limb of an overturned syncline."

Jan 1, 1954

By John S. Stevenson

"Although we have no uranium- producing mines as yet in British Columbia, uranium, associated with gold and cobalt, has been found in two deposits in amounts such that the combined value of the metals not only warrants the further exploration of these deposits, but also encourages the search elsewhere in the Province for other similar deposits.Where uranium-bearing veins have been found in British Columbia, the uranium mineral is the crystalline variety of uranium oxide, uraninite, rather than the massive, non-crystalline variety, pitchblende, such as found in the Great Bear Lake deposit and in other similar deposits along the southwestern margin of the Precambrian shield.The principal occurrences of uranium known so far in British Columbia are associated with bodies of granodiorite and quartz diorite along the eastern side of the Coast Range belt of batholiths. In this part of the Province, interesting amounts of uranium occur on the Gem property in the Bridge River area and on the Victoria property south of Hazelton; and smaller amounts occur on the Red Rose, Rocher Debouze, Delta, and Ohio properties, also south of Hazelton. At the Gem and the Victoria, the uranium mineral, identified as uraninite, occurs in deposits that also contain abundant cobalt-nickel sulpharsenides, and molybdenite.At these properties, the uraninite occurs as clusters of small black crystals of sub-metallic lustre that may be seen upon careful -searching of a highly radioactive specimen with a hand lens. Under the microscope, the uraninite is seen to be in the form of cubes or modifications of cubes that may occur as individual grains widely scattered throughout the gangue or may be gathered into clusters of several grains. The grain size of the uraninite is in general small. Although a few clusters of grains are up to about 10 mesh in diameter, the individual grains, whether in clusters or widely disseminated, are rarely more than 400 mesh in diameter."

Jan 1, 1950

Henry D. Hibbard, High Bridge, N. J. (Communication to the Secretary): There is one chemical factor which has not been considered in the author's tabulation of tests, but which is none the . less important because it cannot be practically estimated, and that is the element oxygen. This element has been, and probably will continue for some time to be, one of the great causes of the continual discrepancies between the chemical and physical properties of steel. Probably oxygen occurs, in important proportions, only in soft steel, such as that which we are now considering. In this steel its physical effect is to diminish tensile strength and elongation. The percentage of oxygen in the steel, under working-conditions that are as uniform as possible, is likely to vary inversely as that of the manganese, or perhaps, and more probably, it may bear even an inverse geometrical ratio to the manganese-content. At all events, to follow the author's plan, the line representing the loss of strength due to oxygen is probably a curve. Plotted by itself, the line would probably be straight; that is, the decrease in strength would be proportional to the increase in oxygen, but if the results were superposed on the percentages of manganese, they would give a curve, because the percentages of oxygen increase faster than those of manganese decrease. Were the oxygen-line to be developed and added to the diagram, it would seem that the manganese-line should then be straight. Due allowance for the effect of oxygen, therefore, would modify two features of the paper. It would increase the figure for the strength of pure iron from 38,000 to about 45;000 pounds per square inch, and it would straighten out the manganese-curve. The manganese-line in the paper is curved between 0.50 and 0.20 per cent. Above 0.50 per cent. it is straight, which may be ascribed

Jan 1, 1893

By Chee S. Theng

As the 2018 president of the Society for Mining, Metallurgy & Exploration Inc., I am pleased to present the 2018 issue of the Transactions of the Society for Mining, Metallurgy & Exploration Inc., Vol. 344. A significant portion of the contribution that we make as a professional society is the publication of professional and technical papers that accelerate the advancement of scientific knowledge and enable the transfer of technology. Communication within the mining community is the key to a successful society. This technology exchange continues a tradition that dates back to the 1871 meeting of 22 mining engineers in Wilkes-Barre, PA, that resulted in the founding of the American Institute of Mining, Metallurgical and Petroleum Engineers (AIME). Those individuals envisioned that these transaction volumes “would form a most valuable and greatly needed addition to our professional literature.” This volume fulfills that pledge. The 2018 Transactions consists of a total of 59 technical papers, encompassing all 25 papers published in 2018 in the Technical Papers Section of Mining Engineering (Vol. 70) and all 26 papers published in 2018 in Minerals & Metallurgical Processing (Vol. 35). Additionally, this volume contains 8 papers that are being published for the first time in this issue. The papers presented in this volume were written by some of the most distinguished professionals in the industry worldwide. All of the technical papers were peer-reviewed. The process of review and publication requires much hard work by authors, reviewers and our Publications staff. As the 2018 president of SME and on behalf of all our members, I would like to extend our gratitude to all whose volunteer efforts contributed to the publication of this volume. The new year brings an exciting change. The publication of Transactions will cease with this volume. Instead, our Minerals & Metallurgical Processing journal has the new name of Mining, Metallurgy & Exploration (MME), and Transactions as well as the Technical Papers Section of Mining Engineering are incorporated into MME. The journal is published in partnership with Springer Nature, and all SME members have free electronic access to the journal.

Jan 1, 2018

By N. A. Barcza

INFACON 7, the seventh International Ferro Alloys Congress, took place in Trondheim, Norway, in June 1995. The main aim of the Congress, which was held under the auspices of Euroalliages and the Norwegian Ferroalloy Research Organization, was to present the challenges facing the ferro-alloys industry on the road to the 21st century. Halyard Tveit, Chairman of the Technical Committee, summarized these as: ? the transition to a single global market economy ? new demands with regards to quality arising from customer needs, and ? increased awareness of the global environment. In the Plenary Sessions Kouichi Nakamura (Nippon Steel) outlined, from the steel industry's point of view, the relationship between technical advances in the products and more demanding ferro-alloy specifications. Advances in steel manufacturing technology and higher product quality have been supported in the past by raising the quality standards of ferro-alloys. Future requirements are bound to bring about more severe standards, and these need to be established by common agreement between both industries.

Jan 1, 1996

By R. R. Sayers

"An important, function of the U.S. Bureau of Mines is to instruct miners in first aid, and as a means of promoting interest in it first-aid contests are held under the auspices of the Bureau, usually in coop; ration with other interested organizations, especially the American Red Cross, the National Safety Council and various operators' and Miners' associations. It was early found that the method of judging first-aid meets is one of the most vital factors in determining the degree of success of the meet.It may be safely stated that there is no method for the judging of first-aid contests that has proved ideal. A method that would give the most uniform judging would necessitate the rating of each team by the same judge or committee of judges and, in order that a judge may rate a team satisfactorily, he should see that team perform several events and average the ratings. Such a procedure is not practicable where there are many terms entered in the contest, as it would prolong the meet indefinitely. To overcome this objection the method has been tried of assigning separate judges to each team but this brings in a new factor the individuality of the various judges, some of whom rate closely, others loosely. The next development was to average the judging by having the judges rate different teams for each event. This would seem to solve the problem out it has been found, after using the method over a wide area for a considerable period of time, that the differences in the judging are too marked to be at all satisfactory. The next development was to appoint a committee of chief judges three to five in number especially trained and experienced, to aid the individual judges in rating the teams. This method has proved satisfactory at small meets but, as committee must review the work of each judge on each event, it has not been deemed feasible for a large meet."

Nov 1, 1920

By G. L. Gates

The waters used to waterflood the Wilmington oilfield were studied by the Bureau of Mines, in cooperation with the city of Long Beach, Calif. Increases in the pressure of the injection wells indicated that they were being plugged by materials suspended in the waters. This study was made to identify the suspended materials, determine their origin, and find methods of preventing their formation. The suspended oil-coated materials were iron sulfide, barium sulfate, calcium carbonate, clay, and sand (or silica). Results indicated that the sulfide, which was as high as 90 milligrams per liter, was the product of sulfate-reducing bacteria. The injection of ocean water increased the sulfate content of the waters in the petroleum reservoirs from 3 to 250 milligrams per liter, thereby furnishing sulfate for growth of the bacteria. The waters were supersaturated with barium sulfate. Laboratory tests showed that sulfide could be removed from the waters by adding iron at a cost of 1 to 2 mills per barrel. The solubility of iron sulfide and calcium orthophosphate in the injection waters was also determined.

Jan 1, 1975

By Hugh Thompson

In mining today, planning is of paramount importance, even more so when one considers that the business margins are reducing, requiring the evaluation of diverse alternatives for the optimal use of scarce resources. Additionally the capital required to approve some projects demands the best planning possible. Modern planning requires that all of the aspects of the business be represented, and not just the planning of the extraction in an isolated form. In order to carry out integrated strategic planning in the mining business one needs to have implemented a culture within the organisation that allows the business to be understood as a interelated system of processes. These processes must be co-ordinated so that they interact properly between each other and so define an integrated plan that optimises the available resources and maximises the benefit to the company. This defined culture should consider the important variables of each activity within the processes, and its’ relevance to the strategic plan. In this sense, this paper shows an example of computer tools used in order to reach the described objectives.

Aug 25, 2002

By Glenn H. Damon

Concern about environmental pollution goes back many centuries, but until recently most efforts to control it have been perfunctory and spasmodic, aimed largely at coal smoke and other visible pollutants. Air pollution is to a large degree a byproduct of our economic development, and scientific knowledge of the causes and character of such pollution is more extensive than the technology to handle the waste byproducts of our industrial civilization. The removal of all constituents foreign to the air from the effluents produced by an industrialized society is obviously impractical at this time. There is widespread difference of opinion regarding acceptable ambient air concentration levels for the Various pollutants produced by combustion processes, but there is basic agreement that the pollution of the atmosphere must be controlled and eventually reduced. The magnitude of the air pollution problem has been increasing rapidly because our expanding economy calls for an ever-increasing consumption of energy, and fossil fuels are a principal source of energy. For example, the consumption of electricity has been increasing at an average annual rate of approximately 8 percent over the last 10 or 1.5 years. Table 1 shows the estimated emission of the principal pollutants into the atmosphere in 1966. The approximately 90 million automobiles, trucks, and buses on American highways contribute the largest proportion of pollutants to the atmosphere, but that fact does not alter the growing problems of the coal industry. You will note that sulfur oxides, particulates, and nitrogen oxides are all products of the combustion of coal. Of these air contaminants, sulfur oxides are now receiving major emphasis in terms of research to develop effective means for control, Table 2 shows that the combustion of coal produces approximately 60 percent of the sulfur oxides discharged to the atmosphere. While the utilization of coal is the principal source of particulate matter, this is not considered as serious a problem as it was in the early part of the century because of technological developments that have produced sound methods for the removal of particulates from waste gas streams.

Jan 1, 1968

By J. E. Drury, W. M. Byers, E. J. Lynch

Measurements made with starch ~~~~s indicate that the Presence of starch serves to depress the streaming potential of a clay mud system. Measurements with pure starch slurries show that the addition of NaCl or CaO reduces the streaming potential significantly. The addition of NaOH, however, causes only a minor reduction in potential even when there are large changes in mud resistivity. INTRODUCTION In their excellent study of the streaming potential, Hill and Anderson' proposed that the presence of conductive solids within the filter medium will reduce the generated potential. This theory was demonstrated with measurements on shaly sandstone cores having various "b" factors; the cores with the higher negative b factors showed markedly lower potentials. (The factor b was originally defined by Hill and Milburn2 in an expression relating the resistivity of a shaly sandstone to the resistivity of the interstitial water: log F, = log F,, + b (log 100R,)'. 'he factor b, therefore, is a measure of the contribution of the conductive solids to the total conductivity of the sample. It has been found experimentally to be directly related to the amount of chemically exchangeable ion per unit pore volume.) In the logical extension of this hypothesis to the streaming potential created by filtration through mud cakes, they suggested that the presence of nonconductive starch in a drilling mud would have the opposite effect; i.e., it would cause the streaming POtential to be increased. The high streaming potentials that they observed with lime muds were attributed to this cause. A cross-plot of some of their results which are relevant to this discussion is given in Fig. 1. The lime-mud curves and untreated-mud curve are taken from curves given in their paper. The gyp-mud line was estimated from their statement that the measured streaming potential for gyp muds in the range of 1.5 to 2.0 ohm-m was approximately 18 mv/1,000 psi. These gyp-mud potentials were the lowest that they reported for any of the bentonitic-clay muds, and were the only ones which were less than the untreated-mud potentials. This very low streaming potential of gyp muds has also been observed in field studies.' By way of comparison, a U. of Texas publication4 gives the approxi-ate compositions for lime and gyp muds shown in Table 1. These materials are added to a bentonitic-clay mud base. It can be seen that both of these muds contain significant amounts of calcium salts and that the gyp mud has the higher concentration of starch. It would appear from this and from the data shown in Fig. 1 that starch may well be the cause of a streaming-potential reduction, rather than a potential increase. EXPERIMENTAL A series of streaming-potential experiments has been performed using a cell of a design similar to that reported by Wyllie.5 Calomel electrodes were used in both the mud slurry and the filtrate. Pressure in the cell was generated with high-pressure nitrogen. The primary objective of the investigation was to determine the effect of starch on the potential. Five different slurries were made which ranged in composition from untreated ben-tonitic mud (Baroid Aquagel) to a pure starch suspension (Baroid Im-permex). The intermediate slurries were prepared by mixing together a 9-lb/bbl clay mud with a 12-lb/bbl starch suspension in the ratios 1:3, 1:1 and 3:1. When starch was used alone, it was necessary to use an 18-Ib/bbl mixture, since leaner mixtures would not form a suitable filter cake. The clay mud used in the experiments was aged for three months before use. In addition to this series of measurements on the starch-clay mud mixtures, other experiments were performed to determine the effect on the potential of the absolute starch and Aquagel concentration, and the effect of adding various chemicals. RESULTS The effect of starch on the streaming potential is shown clcarly in Fig 2. Increasing percentages of starch resulted in n continually decreasing