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By Timothy C. Siegel

Accurate representation of the geotechnical resistance distribution is critical in evaluating the performance of piles and pile groups for design. A current practice is to infer the geotechnical resistance distribution based on measured changes in strain during conventional top load pile testing. Especially for drilled and bored piles, the residual load is typically assumed to be negligible both during testing and after the application of the structure load. A practical result is that the compressive structural load is anticipated to be opposed primarily by the shaft resistance with little or no mobilized toe resistance. The predicted top deflection is estimated as the combined elastic compression plus the movement necessary to mobilize shaft resistance. The development of residual load (and associated negative skin friction) results in a significantly different design condition. Negative skin friction tends to force the pile into the ground and develops residual load in the pile that contributes to the internal compressive load. Significant toe resistance can be mobilized in order to resist the combination of negative skin friction and the sustained compressive load. The pile movement becomes a function of the toe penetration required to mobilize sufficient resistance to reach a balance of forces. In an effort to study the development of residual load in augered cast-in place (ACIP) piles, the authors installed and monitored strain gages that were embedded in an 18-inch diameter ACIP pile at a site in southeast Georgia. The results of this study indicate that residual load develops over time and reaches a distribution that is consistent with the principles of the unified design of piles. It is concluded that residual load develops in ACIP piles (as well as all drilled and bored piles by the same mechanisms) and that the residual load should be considered in the interpretation of load tests and in the pile design, particularly in the estimation of the single pile and pile group settlement.

Jan 1, 2009

By Roger M. Sherman

[Investigation of mine land characteristics, evaluation of irrigation systems, and evaluations by the mining industry, determined that irrigation is a feasible method for aiding revegetation of coal mined lands in western arid and semi-arid regions. The various regions studied displayed a commonality of characteristics which enables, independent of the site or region, the recommendation of solid set irrigation. Irrigation should be supplemental by complimenting natural precipitation and be should implemented on a temporary basis.]

Jan 1, 1980

By Patrick J. Foster

This paper summarises a behavioural safety project undertaken in seven quarries in the UK in order to investigate its applicability as a means of raising the standards of health and safety in the UK quarrying industry. A behavioural safety methodology was developed and trialled at two quarry sites in the UK. During the study the number of unsafe acts and minor accidents had decreased and at one of the quarries there was a 95% reduction in the number of working days lost. It was then introduced at a further five sites of varying sizes and within this focused specifically on lone workers as well as behaviours that affected quality and environmental issues. Positive improvements were noted in most of these operations. The project also looked at the effectiveness of health and safety performance indicators. Here, the common lead and trailing indicators for both safety and health that are commonly used by industry were identified. In consultation with the UK quarrying industry these were then used to identify specific performance measurement criteria that can be used by the quarrying sector to measure performance. Following on from this a quarry specific health and safety management system specification was developed for large and small quarries.

Jan 1, 2008

By Robert Louis Adams

A general discussion of the structure of the junk automobile recycling system shows that the generation of stripped automobile hulks and scrapped automobiles is price inelastic. As a result, it is extremely difficult for the price mechanism to automatically achieve an equilibrium that will prevent the accumulation of excessive automobile wrecker inventories and vehicle abandonment by the last owners of scrapped cars. The new shredder processing technology and the new portable flattener technology have altered the structure of the junk automobile recycling system. The shredder technology has increased the demand for processed automobile scrap. This increased demand is reflected in higher prices paid for hulks by scrap processors. The portable flattener has reduced the transportation cost of shipping hulks to processors. The two new technologies have eliminated, at least potentially, the net cost of shipping stripped hulks so frequently incurred by wreckers in the past. The elimination of this cost eliminates the economic incentive for excessive wrecker inventories. Unfortunately, the incentive for last owners to abandon their cars does not appear to have been eliminated by the new technologies. The last owner of an automobile with no spare parts value is still likely to incur a cost by delivering his automobile to the recycling system. Although a subsidy payment is probably unnecessary to reduce excessive wrecker inventories, such a payment might be one solution to the problem of automobile abandonment. However, there are a wide variety of subsidy programs that could be introduced. Before any Federal subsidy program is introduced to reduce automobile abandonment, it is recommended that the program be tested on a limited basis in many different parts of the country.

Jan 1, 1973

By R. W. Stahl

An award is a form of recognition given for superior performance in a special field of endeavor. Each year awards are given by the Joseph A. Holmes Safety Association and the National Safety Council to mineral industries' mines, quarries, and plants that have worked a specific number of man-hours without a lost-time injury. These awards have a dual significance in that they prove that efficiency can be attained without injury to persons. Safety awards do not result from luck or good fortune but do result from sincere desire coupled with sufficient effort and cooperation to achieve a desired goal.

Jan 1, 1963

Copper waste dump leaching is growing in importance because of the.large tonnages (up to 250,000 ton/day) of low grade waste rock available from open cut mining of copper deposits and proof that controlled leaching of copper from such dumps can be profitable.Overburden or waste rock, ranging in size from large boulders to fines, is dumped as cheaply as possible on sloping sites. Copper is leached from the dumps by applying up to 12,000 gal/min of leach solution (a combination of spent solution from cementation and make-up water) to the top of the dumps by various techniques.Efliuent from the dumps is sent to a cementation plant for copper recovery.Factors which may be controlled, either directly or indirectly, to give a controlled copper content in the dump efliuent (usually 1-2 g/l.) are the cycle of operations (i.e. the alternate wetting and drying periods), thevolume of solution applied to the dump, pH, Fe2+ and Fe3+ content or redox potential, oxygen content, bacteria and their necessary nutrients, and temperature.Dissolution of oxide copper minerals appears to be mainly a function of acid concentration. Copper sulphide minerals need oxidation for dissolution to occur and this is accomplished by a combination of oxygen,ferric ion, and bacteria. Oxidation of pyrite, oxidation of Fe2+ to Fe3 +, and hydrolysis of Fe3+ are of some importance in leaching practice. The presence of gangue carbonate minerals is detrimental.Physical factors connected with penetration of solution into large rocks are important and the treatment of an individual dump usually extends over a period of many years. Recovery of copper from solution is usually achieved by cementation with iron (usually in the form of crumpled cans) but the use of sponge iron is becoming more important. Iron consumption varies from 1 to 4 lbiron per pound of copper. Preconcentration of the copper in the efliuent solution by solvent extraction followed by electrolysis may become a useful method.Application of dump leaching techniques to metals other than copper depends on finding an economic method of recovering the metal from solution...

Jan 1, 1967

By G. Tiess, S. Mujiyanto

Indonesia is a fast growing democratic developing country comprising more than 17,000 islands, founding member of ASEAN and a member of the G-20 major economies. It is one of the most highly mineralised countries in the world, the mining sector playing a pivotal role in the country's economy. In 2001, the Decentralization Law No. 22/1999 came into force and caused a transfer of authority and responsibility from central to regional and local administrative governments. The new Mining Law of 2009 substituted its 40 year old predecessor, but lacked detailed regulations for its implementation. These were only issued in 2010, which lead to a period of great uncertainty for investors in the mining industry. The new legislation intends to foster domestic economic development, which may be interpreted as protectionist policy. For the development of a sustainable mineral resources policy, further endeavours will have to be made.

Jan 1, 2011

By The Staff

THE object of the work was to increase the capacity of the plant and, if possible, to reduce costs of the actual unit grinding while doing so. The accompanying assays of an infra-sizer analysis of the cyanide tail (Table l) illustrate the problem in hand. The cyanide tail is a combination of two products, gangue and FeS2. The assay alters by virtue of a change in gold value due to grinding and the relative quantity of FeS2 in the sizes, which itself varies with the grind. The disposal tail is the residue after the cyanide tail is scavenged by flotation, most of the pyrite being removed for roasting. It presents a somewhat different problem, since grinding gangue is all gain, but -10 micron FeS2 does not float nearly as well as + 10 product. This results in compromise in the final size to be aimed at. Extra grinding has hardly any appreciable effect on the gold extraction from the FeS2. (See Milling Investigations Into the Ore as Occurring at the Lake Shore Mine; Trans. C.l.M.M., Vol. XXXIX, 1936).

Jan 1, 1940

By Francis C. Lincoln

"INTRODUCTION In the course of a general investigation of mines and mineral deposits in the Upper Mississippi lead and zinc field, attention of the Bureau of Mines was first directed to the Coker mines area by the presence of large tonnages of old mill tailings containing economically recoverable percentages of lead and zinc. Later, the results of extensive geologic studies of the area were presented to the Bureau of Mines by the Federal Geological Survey, directing attention to the possibility of extending the known ore limits of the area to the north and northeast of the old Coker No. 1 mine workings.With this end in view, the Bureau of Mines undertook a program of churn drilling and sampling. This report describes the work done and presents the data obtained during the period of the Bureau of Mines investigation.ACKNOWLEDGMENTSIn its program of investigation of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. The Mining. Division, Lowell B. Moon, chief, conducts preliminary examinations, does the actual investigative work, and prepares the final report. The Metallurgical Division, O. C. Ralston, chief, analyzes the samples and makes beneficiation tests."

Apr 1, 1948

By Bohrn W, Milionis K, Tessmer G, Reidetschlager J

The share of electric arc furnace based steel production is increasing - New technologies for the production of virgin raw materials for EAF production are under development and on the market - VAI has a strong position in the field of scrap substitution technologies with their COREX«-, COREX«-DR and FINMET«-technology. In late-1998 the steel plant SALDANHA was started up successfully. This integrated compact mill is using the COREX«-technology as hot metal and a combined DR-plant as DRI production unit. Also in 1999 the BHB FINMET« plant Port Headland went on Stream.

Jan 1, 1999

By R. Altindag

Engineers and researchers need to estimate the mechanical properties of rocks from P-wave velocity. In previous studies, the researchers have investigated either the limited values or all the data belonging to sedimentary, igneous, and metamorphic rocks together in the same statistical analysis. In this study, the raw data pertaining to only sedimentary rocks was taken from previous studies and evaluated. For this purpose, a total of 97 samples of sedimentary rock types were subjected to statistical analysis. First, the relationships between P-wave velocity and physical-mechanical properties were investigated by simple regression analysis. All the data were then subjected to multi-regression analysis. Some empirical equations with high correlation coefficients were derived for rock engineers. The equations obtained from the analyses are compared with previous equations found in literature.

Jan 1, 2012

By John H. Soule

Although known since 1902 , the Capitan iron deposits have not been mined mainly because of the low grade of the ore . A small amount of exploratory work carried on at an early date was reported . C. E. Johnson , district engineer of the Bureau of lines for New, Mexico , visited this propert , and as a result of preliminary sampling and mapping by the Bureau3/ and the Federal Géological Survey , an exploratory project was conducted during March , April , and liay 1944. Further mapping and logging of the vagon -drill samples was done by V. C. Kelly , geologist , of the Survey .

Mar 1, 1947

By E. O. RHODES

Germany's' wartime coal-tar industry had two main branches, which can best be considered individually because their raw materials, operations, and distributions were almost completely separated. One branch, old and well-established, was concerned almost entirely with processing coal tar produced by the high-temperature carbonization of caking bituminous coal. Carbonization was effected principally in byproduct- coke ovens and to less extent in vertical, horizontal, and inclined retorts. The high-temperature tar was all processed in tar-distilling plants that handled high-temperature tar almost exclusively.

Sep 1, 1947

By K. Pirapakaran

The Geotechnical Engineering research group at James Cook University has been working closely with all the leading mines in Australia in the area of minefills. They have carried out substantial research and consulting work on the drainage and stress developments within hydraulic fills. The objective of this paper is to summarize their work during the past five years on hydraulic fills. The paper will serve as a one-stop reference, pointing to relevant literature including the authors? own publications, on various issues covering drainage and stress developments within hydraulic fills. More than 15 different hydraulic fills, representing five major mines in Australia, were studied. Their grain size distributions and placement characteristics including permeability, porosity and dry density were studied and comparisons were made with the limited in situ data available in the literature. Stress development within hydraulic fills has been studied to minimize the risk associated with barricades failure. FLAC and FLAC3D were used to model stress developments within the hydraulic fills and were compared against the approximate closed form solutions available in the literature. A laboratory model was developed to study arching effects within the hydraulic fills.

May 1, 2007

By R. L. Peyton

Risk analysis is used extensively in many engineering applications. Although its use in the field of dam safety has been limited in practice, it has received considerable attention in recent years in the dam safety literature. Thus far, it has been shown that risk analysis in the evaluation of existing dams has the potential for providing a more rational basis for decision- making because of its focus on the direct issues--likelihood of failure, likelihood of loss of life, and risk cost of damages. It provides for a logical balance between the risk a dam imposes and the degree to which rehabilitation is required, compared to traditional evaluations based on somewhat arbitrarily chosen design events applied to large classes of dams. Dam owners could benefit by optimizing the cost of remedial measures. Downstream landowners could benefit by minimizing the likelihood of flood damages. However, it is also clear that significant technical and policy issues remain to be resolved before risk analysis in dam safety is accepted and routinely implemented in engineering practice. An obvious and important potential application of risk analysis is its use by the state regulatory agency as an in-house evaluation tool, or even as part of regulatory policy, in the implementation of its state dam safety program. Adoption of such a policy would have an important impact on the mining industry. .Although no state dam safety programs are known by the writers to have officially incorporated risk analysis into their regulations, there appears to be considerable interest in the concept. In recent surveys 47 states agreed that the development and promotion of a risk assessment methodology for state dam safety programs should be encouraged (Tschantz, 1983; Tschantz, 1984). The issue has also received important attention within the Association of State Dam Safety Officials (1986). One state-Illinois-proposed regulations during 1986 to allow risk analysis to justify lower spillway requirements for existing dams (Illinois Department of Transportation, 1986). At the Federal level, the National Research Council has found risk analysis especially appropriate for assessing dam safety at high-hazard dams (National Research Council, 19851, the Bureau of Reclamation has published guidelines for incorporating risk analysis into their dam safety grogram (U.S. Department of the Interior, 1986), and the Federal Emergency Management Agency has recently sponsored workshops and supported research related to risk analysis in dam safety (Federal Emergency Management Agency, 1985a ; Federal Emergency Management Agency, 1985b; - - McCann, et. al., 1985a, 1985b).

Jan 1, 1986

By J. -P. Gisiger

On the basis of laboratory test results a comparison of various parameters (unconfined compressive strength, CERCHAR and LCPC abrasivity indexes, mineralogy) is presented and discussed in order to outline certain correlations between them. Samples cover a wide range of lithological types coming from various sites of tunnels. A partir de résultats d’essais de laboratoire, une comparaison de divers paramètres (résistance à la compression simple, indices d’abrasivité CERCHAR et LCPC, minéralogie) est présentée et discutée dans le but d’en tirer certaines corrélations. Les échantillons couvrent un large éventail de types lithologiques provenant de plusieurs sites de tunnels. Basierend auf Laborversuchen, werden verschiedene Gesteinseigenschaften (Druckfestigkeit, CERCHAR und LCPC Abrasionsindexe) präsentiert und Korrelationen aufgezeigt. Die untersuchten Proben verschiedenster Lithologien stammen aus mehreren Tunnelprojekten.

Jan 1, 2003

By Manuel Gomez

This report presents prediction equations for 12 variables that are indicative of metallurgical coal quality. The variables include six for coke strength and six for carbonization product yields. All variables were predicted for coking coals having volatile matter contents from 16.3 to 42.1 percent, dry basis. The prediction equations, developed by mathematical-statistical techniques, were based on information from the proximate and ultimate analyses, the size consist, and the petrographic composition of bituminous coals carbonized in BM-AGA retorts at 800°, 900°, and 1,000° C. The equations were evaluated for validity with independent data derived from the 900° C carbonization of 33 binary blends of various coals and 22 binary blends of Pocahontas No. 3 low-volatile bituminous coal with 11 high-volatile bituminous coals. Results show that metallurgical coal quality can be predicted ahead of mining because data used to derive the prediction equations can be obtained at the time of exploration. Capability to forecast coal quality is useful in mine planning and should provide basic information for optimization of blending and crushing techniques and thus lead to the production of uniform coke.

Jan 1, 1970

By Trevor Hamm, Nick Holl

"Cameco Corporation is operator of the world's richest uranium project, the Key Lake mine/mill complex, located within the Athabasca region of Northern Saskatchewan. Mineable resources from the Key Lake ore bodies with an average U,08 content of 2.5% will be exhausted by the year 2000 and open pit mining at Key Lake will be phased out at that time. The mill will continue to operate at increased capacity, using high grade ore from the McArthur River project, a new underground mine at a distance of about 80 km from the Key Lake site. The McArthur River ore with an average U308 content of about 15 % will be blended with separately stockpiled low grade materials from Key Lake with a U,08 content of about 0.1 %. The average (blended) mill feed grade will be about 4%, similar to peak concentrations found in Key Lake ore.The Key Lake ore tailings are presently being placed in the mined out Deilmann pit under sub-aerial conditions, using spigots and a highly efficient pit/tailings drainage system. The tailings resulting from the processing of the blended McArthur River ore will be deposited on top of the Key Lake ore tailings under sub-aqueous conditions. This staged approach shows distinct technical and environmental advantages over an alternative, fully sub-aerial in-pit deposition scheme.The first part of this paper presents an overview of site specific geotechnical and hydrogeological features found at Key Lake and details some of the extensive test and modelling work that was required for environmental impact predictions during the development phase of the facility. The second part of this paper deals with tailings modifications, innovative placement technologies and drainage methods that have been (and will be) employed at the Deilmann Tailings Management Facility {TMF) to produce a highly consolidated tailings body under non-buoyancy conditions. The application of this technology at Key Lake is expected to produce a tailings ""plug"" in the Deilmann TMF which will have a permeability similar to or lower than the original in-situ Deilmann ore, resulting in a minimization of contaminant mass loadings to the environment both during operation and after decommissioning."

Jan 1, 1998

By Barnettm Ray R.

As a result of the Farmington explosion, the U. S. Bureau of Mines commissioned the National Academy of Engineering to a determine what steps could be taken in a short time frame to significantly reduce fatalities as a result of underground fire and explosion in coal mines. Three areas were named by the Academy as having the greatest potential; survival, communications, and rescue. The Bureau subsequently awarded a $3-5 million contract to the Special Systems Division of Westinghouse Electric Corporation for the development of prototype equipment and procedures. These were recently tested in a simulated emergency situation and will be delivered soon. Contractor recommendations for utilization and for further development effort will be studied and appropriate action taken.

Jan 1, 1971

By Bernard Dallaire, Jean Cayouette, Sylvain Duchesne

"Louvicourt Mine's concentrator, located near Val d'Or, Quebec, treats an average of 4,300 tonnes of ore per day composed mainly of copper, zinc, gold and silver. An analysis of concentrator revenues and metallurgical losses shows a potential for additional gain, particularly in regards to precious metals (kustelite) where recovery is usually around 67 -70 %. The planning, installation and trial operational period of two Outokumpu SK-240 flash cells at the underflow of the primary cyclones took two years. The use of (( flash flotation )) technology has made it possible to exploit the favourable conditions at the underflow of the primary cyclones such as precious metal concentration and the presence of liberated coarse chalcopyrite. These conditions permit early flotation (fresh surfaces) of the kustelite and the liberated copper. Since the start-up of the flash cells, the metallurgical gains have turned out to be very positive with increases in metal recovery reflected in appreciable NSR gains. Also, significant savings in reagent consumption and a coarser copper concentrate have made it possible to reduce the drying cycle of the Larox filter presses since the cells were put into operation.BACKGROUNDLouvicourt Mine is operated by Aur Resources Inc. (30% ownership) on behalf of its partners Novicourt Inc. (45%, subsidiary of Noranda Inc.) and Teck Corp. (25%). The mine is located in northwestern Quebec about 600 km north of Montreal and about 25 km east of the mining town of Val d'Or. The mine commenced commercial production in July 1994.The massive sulphide ore deposit lies at depths varying between 450 m and 900 m. Mining reserves (2% Cu equi. cut-off) as of Jan. Is', 2000 are estimated at 7.5 million tonnes of ore averaging 3.4% Cu, 1.8% Zn, 28.0 g/t Ag and 0.9 g/t Au. Delineated ore reserves permit the use of a mechanized transverse blasthole mining method. The extraction order is a typical 1.3.5 mining sequence. Primary and secondary stopes are 15 m wide, 15 to 70 m long (25 m long average) and 30 m high. Backfilling for pillar recovery and regional stability is required."

Jan 1, 2001