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By Allen G. Taylor

High-value materials, such as gold, platinum and other precious metals, are subject to loss through unauthorized removal from mines, smelters, refiners and other places where such materials are processed. A study by Gastrow (2001) determined that between 1994 and 1998 an average of 603 kg/a (1,330 lb/year) of gold was stolen from South African mines and subsequently recovered. This does not include the gold that was stolen but not recovered. At 2011 prices, 603 kg/a (1,330 lb/year) of gold would be worth approximately $33 million. Mine security personnel believe that the unrecovered stolen gold far exceeds what is recovered (Gastrow 2001). Traditionally, metal detectors have been used to screen personnel leaving secure areas to discourage such unauthorized removal. However, with the current near-record prices of gold, platinum and other precious metals, it has become worthwhile for people exiting a facility to walk out with quantities of product that are too small for ordinary metal detectors to register, resulting in substantial financial losses.

Jan 1, 2012

By J. J. Jakosky

THE method of electrical mapping of oil structures to be described possesses certain limitations, as well as certain definite advantages. It, in common with other geophysical methods, is not a panacea for the solution of all subsurface geological problems. It operates on differences in electrical conductivity of the geological strata, whereas the other most-used methods operate on (1) differences in magnetic properties, (2) differences in gravimetric properties, or (3) differences in seismic properties. This modification of the resistivity method is therefore able to obtain subsurface information under conditions not favorable to the other methods mentioned. Where the other methods have been employed with ambiguous results it may act as a complementary method.

Jan 1, 1936

By Michel Lefebvre, André Piché

Every organization performing R&D is faced with the challenge of introducing new technologies to its operations. Difficulties must be overcome if companies are to realize the benefits anticipated from such developments. This paper outlines the difficulties encountered in transferring to operations various technologies developed at the Mining and Exploration Division of the Noranda Technology Centre. The approach used in the selection of a privileged partner for the technology transfer, the criteria motivating the choice and the process followed to establish the partnership are presented.

Jan 1, 1997

By W. E. Selnes

Introduction In 1938, a survey conducted by the Ontario Mining Association revealed a rather startling fact. Injuries incurred in chute pulling were more numerous than those from any other single cause. This report prompted Mr. W. B. Paton, then Inspector of Mines for Manitoba, to make a similar survey of the mines of his Province. It indicated that, in Manitoba mines, chute accidents ranked second only to those from falls off roofs and sides. Why has the mining industry been so slow to recognize the dangers of chute pulling? A partial answer may be the lack of any systematic classification of accidents according to their real cause. The result has been to attribute to other causes injuries which were a direct outcome of chute pulling, and, indeed, has made it difficult to analyze accidents in the industry as a whole. Perhaps, too, because chutes are generally located in the comparative safety? of the drifts, there has been a tendency to consider the occupation as not very hazardous. Not until enough statistics were obtained on this particular task could it be appraised correctly. The Mining Association's survey has been most helpful, and latterly the industry has done a great deal toward analyzing the causes of chute accidents and toward determining an effective means of overcoming them. Much, however, remains to be done. An effort will be made in this paper to outline methods which have been found successful in materially reducing the number of injuries. Qualifications of the Chute Puller First of all it must be realized that chute-pulling is a specialized occupation. The men require proper training for the job, just as in other mining operations. Care must, therefore, be taken to choose persons whose qualifications fit them for the job. Chute-pulling is an integral part of the general mining operation and cannot be considered as isolated from the tasks of other workers. One of the essential qualifications of a chute-puller is a sufficient knowledge of mining operations to appreciate the effect his work will have on the safety of others in the vicinity. He must take the necessary precautions, by verbal warnings, by placing barricades and signs, or by personally guarding the chutes, to prevent accidents to fellow workers.

Jan 1, 1947

By Gieskieng, D. H.

Published tables of jaw crusher capacities are compiled for the most part from field performance data, interspersed with interpolations, extrapolations, various safety factors, and other modifications. Such a table attempts to balance and equalize field data from widely different materials, with differences of crushability, efficiency of feeding, sizing of the feed, and so on. The tests described in this paper were undertaken with the objectives of checking previously reported capacities; of studying the effects of various factors upon the capacity, including jaw plate curvature; and, if possible, of deriving a general capacity equation. Such an equation has been derived from the data obtained in these tests. It is given together with factors for its use. While more accuracy than is usually required may be obtained by careful application of the equation, it is of simple form and provides a convenient reference plane upon which the potential capacity of various crushers may be compared, and with which operating adjustments may be made on existing installations. The principal deviation in these tests from the usual approach consists of a laboratory technique which has been developed for the production of selected

Jan 1, 1949

By Phillip B. Bucky, R. S. Taborelli

The term "longwall mining" is best known to coal men, although modifications of the method are continually being used in other fields. Longwall mining is of interest today because it makes for greater inechanization and better supervision at the working face, and therefore lower production costs and increased safety. It is an approach to the factory system of production, the high efficiency of which as compared to that in mines is well known. There is available an accumulation of experience regarding this work but coordination of experience is lacking and this series of experiments was undertaken to help serve this purpose. Model experiments were used for reasons of safety, cost and time, and because it has been previously shown1,2,3 that a scalar inodel built of the same material as the prototype will behave in a manner similar to that of the prototype, with time effects the same, if the effective weight of the model is increased in the same proportion as its linear dimenbions are decreased. This is accomplished by substituting a centrifugal for the gravitational field; i.e., placing the model in a centrifuge and controlling the strength of the centrifugal field by varying the rate of rotation. Many factors affect the behavior of the geologic material overlying a bed, therefore results and conclusions contained in this paper apply only to the conditions presented herein. Longwall Mining What Is Longwall Mining?—Agreement should be reached as to what constitutes longwall mining and therefore what constitutes a longwall face. Let longwall mining be defined as the mining procedure in which the roof and overlying bed breaks tend to parallel the working face. In the ordinary stope or room-and-pillar mining the roof breaks tend to

Jan 1, 1938

By Phillip B. Bucky, R. S. Taborelli

The term "longwall mining" is best known to coal men, although modifications of the method are continually being used in other fields. Longwall mining is of interest today because it makes for greater inechanization and better supervision at the working face, and therefore lower production costs and increased safety. It is an approach to the factory system of production, the high efficiency of which as compared to that in mines is well known. There is available an accumulation of experience regarding this work but coordination of experience is lacking and this series of experiments was undertaken to help serve this purpose. Model experiments were used for reasons of safety, cost and time, and because it has been previously shown1,2,3 that a scalar inodel built of the same material as the prototype will behave in a manner similar to that of the prototype, with time effects the same, if the effective weight of the model is increased in the same proportion as its linear dimenbions are decreased. This is accomplished by substituting a centrifugal for the gravitational field; i.e., placing the model in a centrifuge and controlling the strength of the centrifugal field by varying the rate of rotation. Many factors affect the behavior of the geologic material overlying a bed, therefore results and conclusions contained in this paper apply only to the conditions presented herein. Longwall Mining What Is Longwall Mining?—Agreement should be reached as to what constitutes longwall mining and therefore what constitutes a longwall face. Let longwall mining be defined as the mining procedure in which the roof and overlying bed breaks tend to parallel the working face. In the ordinary stope or room-and-pillar mining the roof breaks tend to

Jan 1, 1938

By A. G. Roach

MILLING of Nova Scotia gold ores began in 1862 with arrastras and wooden stamps and has progressed to heavier stamps followed by tables and other forms of concentration for the recovery of the sulphides. Chlorination and cyanide leaching of the concentrates has been practised, and in 1936 the combined amalgamation and all-sliming cyanidation plant of Seal Harbor Gold Mines was built. It has since been found that it is not necessary to cyanide the full tonnage and now only the concentrates are being so treated. From his experience in this enterprise, the writer presents the accompanying flow-sheet and supporting comments. While he has not the temerity to maintain that it is the best or only flow-sheet for Nova Scotia gold ores, he feels that it warrants thoughtful consideration by members of the milling fraternity of the Province. THE ORE The gold in Nova Scotia ores occurs both free and intimately associated with sulphides-chiefly arsenopyrite. Much of the free gold is quite coarse and crystalline. This is especially true when it occurs in white quartz. When in the slate, it is usually in thin plates and scales, frequently coated and discoloured. The values bound up in the sulphides are not amenable to amalgamation and must be recovered by other methods-concentration, followed by smelting or fine grinding and cyanidation. While high freight and treatment charges apply on concentrates shipped from the Province to smelters, a considerable quantity has been so disposed of in the past. However, it is hoped that a customs cyanidation plant will soon become available to producers of these auriferous concentrates in Nova Scotia.

Jan 1, 1938

Jan 1, 1882

By Jerome P. Downey

Technologies developed within the field of extractive metallurgy to recover, concentrate, and purify metals and industrial minerals from ores, have served as the foundation for all of the subsequent environmental remediation, materials recycling, and waste management technologies. This paper discusses the application of classical extractive engineering principles to the development of a thermal process for the recovery of mercury from solid wastes. Process development is presented as a series of logical stages, which begin with a thorough characterization of the site-specific waste, move on to bench and pilot scale testing of the process options, and end with a functional process flowsheet. This paper also presents thermodynamic data on many mercury species of interest to the minerals, power, and chemical industries. These data can be used to model the speciation and recovery of the mercury as a function of various process parameters.

Jan 1, 2003

By G. A. Campbell

Mining companies have been very interested in the presence of a number of small but high-grade ore bodies of base metals in northern Wisconsin and the west/central section of the Upper Peninsula (UP) of Michigan. The region is rural with outdoor recreation/tourism and lumbering being the key industries. The economy of the region is based on the use of its natural resources, and mining is not a new activity to the region, especially the UP. The western UP was historically a key mining district for copper and iron, and today the central UP has a significant iron-mining district. However, all efforts to develop the base metal ore bodies have been met with a storm of controversy involving the local community, regional activists, Native Americans, and the state government, and only one mine has gone into operation. There is concern by some stakeholders about the sustainability of mining in communities that depend on the environment for tourism, recreation, and other commercial activities. There have been four attempts to get the necessary approvals to mine in this region: the successful Flambeau Mine effort (Wisconsin), the failed Crandon project (Wisconsin) and Lynne project (Wisconsin) efforts, and the continuing effort to get the Eagle Project (UP of Michigan) approved. The cases are presented to illustrate the project situation, the history of the permitting effort, and the opposing parties and their concerns. The case of the Eagle Project is looked at in detail by using the method of discourse communities and discourse analysis. Results of the analysis provide insight into the communication efforts to address community concerns about sustainability and what more can be done to improve this dialogue.

Jan 1, 2008

By B. Catalano, D. Ifrim

The Annacis Island Outfall Project includes two TBM bored tunnels with face pressures above 3.5 bar, with an internal diameter of 4.2 metres. This paper discusses the innovative approach to TBM tunnelling and TBM design at the Annacis Outfall Project. The TBM custom design includes a 3.6 m OD core machine manufactured by Herrenknecht and a 5.0 m add-on by the Contractor (Bessac), acting as an extension kit, with optimized gantry design to accommodate for short tunnel drives and quicker launches. This novel design approach produced safety improvement, cost and schedule savings while streamlining logistics of TBM retrieval.

Dec 1, 2022

By Atul Bhatnagar, M. P. Sinha, Md Zahid Ahmad, Pallav Garg, Sanjay Kumar Singh, Shashi Ranjan, An Ecolab Company Nalco Water

"Froth Flotation is undoubtedly one of the most critical processes in coking coal washing plants. This work was carried out at Bhelatand Coal Preparation Plant of Tata Steel was with an objective of cost optimization in fine coal processing. The sources of raw coal for the plant include coal from underground mines of Jharia coalfield and procured open-cast raw coal. Coal from different sources vary in quality and possess different floatability characteristics.Synthetic collector is being used in plant as a flotation reagent. An alternate collector with new chemistry was developed for reducing total treatment cost without compromising product yield and quality. A series of laboratory tests were conducted to assess the performance of various sources of raw coal and plant scale trial was started. At first, the new generation coal collector was entirely substituted with the existing collector in the laboratory scale. However the plant scale trial data was not in accordance with laboratory results and indicated inferior flotation performanceThe issue was studied and data based conclusions were drawn that the new generation collector aids faster and uncontrollable kinetics. A decision was taken for co-dosing of the synthetic and new collector for the second phase of the trial. A detailed laboratory analysis was done again and few dosing ratios that predicted optimum results were selected for plant trial. The dosing ratio was optimised as per flotation yield and product ashes during the plant trial. The results showed significant improvement from the first phase and optimum dosing rates were decided based on plant observations and data collection. The influence of various process indicators including water quality, feed and product ashes and process yield was studied during all the trials and promising results were established. The co-dosing of both the collectors conferred cost advantage and enabled to achieve superior performance."

Jan 1, 2016

By Joseph Daniels

When Dame Nature shook her horn of plenty and distributed her bounties over the face of the earth, she blessed the Pacific coast with many riches, but with these she added many offsetting disadvantages or handicaps, designed, no doubt, to effect a proper balance between wealth and economy. Nowhere is the application of the law of compensation more aptly illustrated than in the matter of fuel and power resources. A glance at the map of the Pacific northwest will show that west of the Coast Range batholith we are bounteously supplied with coal, with timber, with water power, and with tributary resources of oil from California. Alaska, British Columbia, Washington, all contain large resources of coal; Oregon and California to a lesser degree, but, compensating the golden state for its deficiency in this respect, oil was placed in the treasure ,chest. Timber, of wide variety and in lavish quantity, covers the forests from tidewater to mountain slope, and within this protected watershed area flow streams which give the Pacific coast states the largest single share of the potential water-power resources of the country. Something over 40 per cent. of the total estimated horsepower of the United States is to be found in the Pacific states, and British Columbia has 15 per cent. of the total for Canada; but of this total less than 10 per cent. has been developed.

Jan 1, 1924

By Esther Carrera Martinez

Caraiba Metals is the sole brazilian copper custom smelter. The sulfur present in the various concentrates processed is recovered as sulfuric acid and oleum ,which are sold in the local market For quality assurance purposes, a study was carried out in order to determine how to control the arsenic content in the acid, allowing the continuous processing of concentrates with high levels impurity, The study was based on the process parameters of the washing towers and mist precipitators, Others process variables were investigated and their effects were used in support to confirm the results, After many analyses performed some interventions to improve the quality of the acid were implemented in the plant, which proved to be successful even by using a conventional purification system,

Jan 1, 1996

By Faruk Oksuz, Dave Schiemann, Matt Trotter, Mike Padilla, Miguel Sanchez, Carmen Scalise

"Chicago’s Tunnel and Reservoir Plan (TARP) is a nearly $4.0 billion and over 30 years long program and arguably the largest and longest combined sewer tunnel and reservoir system in the world. Recently, a massive tunnel construction is underway for connection of the McCook Reservoir to the existing TARP tunnel system. Once completed in two stages in 2017 and 2019, the reservoir will hold 38 billion-liters (10 billion-gallons) of combined sewer overflows (CSO) and flood waters from the city of Chicago and over 20 communities in Cook County, Illinois. McCook Main Tunnel will connect Chicago TARP’s Mainstream Tunnel to the McCook Reservoir. Connecting two 10-meter (33-ft) diameter tunnels at 92 meters (300 feet) underground has not been a simple task for the McCook Tunnel Project participants, the project owner U.S. Army Corps of Engineers (USACE), local sponsor Metropolitan Water Reclamation District (MWRD) of Greater Chicago, designer Black & Veatch, and the contractor, Kiewit Infrastructure Company (Kiewit). Yet alone excavating and lining massive size tunnels, the team is also challenged with live tunnel conditions in TARP Mainstream Tunnel that carries CSO and flood flows from city of Chicago which runs full during rain events and must remain in service at all times. The project is a noteworthy feat for engineering and construction with the upcoming installation of world’s largest underground wheel gates for flow control within the tunnel. In this paper, we describe one of its kind elements of this major tunnel system along with key design and construction considerations, specifically for the live tunnel connection which is a rare occurrence in the tunneling industry. INTRODUCTION The McCook Main Tunnel system consists of a 10 m (33 ft) finished diameter and 490 m (1,600 ft) long hard rock tunnel constructed from a 27.5 m (90 ft) diameter and 92 m (300 ft) deep main gate and tunnel construction access shaft. The gate shaft houses six high head 4.4 m by 9 m (14.5 ft by 29.5 ft) wheel gates to be installed in the bifurcated and steel lined section of the tunnel. The tunnel also includes portal and energy dissipation structures as it daylights into the reservoir."

Jan 1, 2016

By Jeffery L. Kohler

The research and development of a pattern recognition system which can predict incipient failures and safety hazards in the mine power network is described. An examination of mine electrical safety hazards revealed they are often related to the electrical equipment down-time experienced on mine sections. Based on this, a method is proposed that can improve both production and safety, without compromising either. Equipment failure modes are examined to illustrate how the ultimate failure can be predicted for enough in advance to allow a convenient and safe repair, followed by a discussion of actual monitoring system performance. Finally, the paper is concluded by projections of the system's utility to industry.

Jan 1, 1977

By P. Altounyan

Techniques used to safely control the roof in UK coal mines for some 10 years have been applied to a South African coal mine. This new approach known in the UK as advanced rockbolting technology, is based on applying four fundamental principles: ?Understanding the roof failure mechanisms ?Using an effective roof support system ?Designing this support using measurement ?Monitoring the performance of the system. The paper summarizes the approach in detail and describes how it is being applied by Anglo Coal, giving results obtained to date. Investigations at a number of South African coal mines, including stress measurements at two Anglo Coal mines, have confirmed that the mode of roof failure (lateral shearing due to horizontal stress) is the same as in other coalfields worldwide, and aspects of current world best practice, including the use of advanced technology rockbolting, are therefore relevant in South Africa. The stress measurements indicated a high level of stress field anisotropy and further investigation of stress conditions in South African coal mines is recommended. The most effective bolting system to resist shear failure is one with high bond strength and stiffness. Short encapsulation pull testing of existing South African systems confirmed that they have low bond strength and stiffness. An improved rockbolt system with the required performance, and features allowing rapid installation and installation quality and performance audit, has been developed and is currently under full-scale trial. Design by measurement and routine monitoring procedures including the use of a rotary telltale device are also under trial. It is anticipated that South African coal mines will be able to obtain significant safety and productivity benefits from the application of this technology.

Jan 1, 2001

By Charles M. Rolker

(Read at the Philadelphia Meeting, February, 1878.) THE Mariposa estate, a grant made by the Mexican Government to Juan B. Alvarado, during the time when California was still under the dominion of Mexico, was purchased in 1847 by J. C. Fremont, and the United States patent issued to him in 1856. By sale, or its equivalent, money advanced, the property came into the hands of the Mariposa Company, June 25th, 1863, and through a varied existence of work and temporary inactivity, has as yet been kept as an undivided property, and rests at present with the Mariposa Land and Mining Company of California. I pass over this period of 15 years without giving the history of the ups and downs of the estate, partly because it is familiar to many, and also because I think in such a case this paper would assume too much the character of a narrative. The estate is situated in Mariposa County, California, about 170 miles southeast of San Francisco. It begins in lat. 37° 26’ 38" - north, and long. 119° 55' west, and runs 6 miles north; thence 6 1/2 miles west; thence 5 miles northwesterly towards the Merced River; thence 8 1/2 miles southerly; thence 3 miles easterly; thence 1 mile southerly; thence 2 miles easterly; thence 2 miles southerly; thence 2 miles easterly; thence I mile southerly; thence 2 miles easterly; thence 1 mile northerly, and thence 2 miles easterly to the place of the beginning; embracing 44,387 acres (70 sq. miles) more or less. To describe this vast estate in detail as to its full geology, its numerous quartz veins, its many facilities to exploit them and work them by cheap methods, would lead me further than I intend to go at present, and I will content myself to describe the latest workings of the company and its immediate field of operations. As long ago as 1860 the late Dr. Adelberg advised the running of an adit from the northwestern edge of the estate at Benton Mills on the Merced River. His object was to undercut the deepest workings of the then paying mines on the estate-the Pine Tree and Josephine. Following this advice, the tunnel known as "River Tunnel" was commenced. Its entrance is in S. 5, T. 4, S. R. 17 E. It is run in

Jan 1, 1878

This report is in fulfillment of Contract H0230031 awarded to Bituminous Coal Research, Inc., on May 23, 1973. The scope of work to be performed under this contract was divided into four phases: Phase I - Design, Phase II - Construction, Phase III - Field Demonstration, and Phase IV - Analysis and Final Report. During Phase I, an agreement was finalized with the Rochester and Pittsburgh Coal Co. for conducting field tests of the proposed shearer spray systems on a longwall panel in the company's Jane Mine in Indiana County, Pa. A drum was then designed which could be used on the Eickhoff shearer, Model EW170-L, being used on this longwall and which would utilize the following spray systems: 1. One spray nozzle located in front of each cutter bit with the jet directed at the cutting surface. 2. One spray nozzle located in back of each cutter bit with the jet directed at the back of the bit. 3. Standard Eickhoff nozzles located in a header along the drum scrolls. 4. A fixed header mounted on the shearer directly behind the drum to simulate the spray system originally used on the Eickhoff shearer.

Jan 1, 1976