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By James E. Myers

This study is a survey of the current "state-of-the-art" of commercially-available sonar tools to monitor the true shape of man-made cavities within the Hutchinson Salt of south-central Kansas. The work entailed ferreting out the available information, most of which is proprietary in nature; then examining actual existing conditions and arriving at a reasonable scientific evaluation of the method. Our studies were confined to one LPG field and two brine well operations in south-central Kansas. No field testing of any devices was performed, only questioning user firms, and studying cores, logs, and sonar surveys graciously made available by the companies we have contacted. Since these data are still somewhat proprietary, the company participants have asked that their company names be omitted from this presentation.

Jan 1, 1973

By E. W. Greig

This paper is an account of exploration for bauxite in the Amazon Basin, Brazil, and particularly of the discovery, exploration and development by Alcan of the Trombetas deposit so a general account of the Trombetas Project has already been published in E/MJ (Anon. 1975) to which the reader is referred for details on owner-ship, infrastructure and construction as well as the proposal for mining and treating the bauxite. It is impossible to consider the Trombetas deposits in isolation. A regional account of bauxite in and around the Guyana Shield and the northern portion of the Brazilian Shield is included and it is suggested that these deposits all formed during Tertiary time under similar conditions.

Jan 1, 1977

By G. R. Burman

Gilsonite is a brittle, natural solid bituminous resin, classified as an asphaltite. It is found in near-vertical veins in the Uintah Basin of Eastern Utah. Discovered well over 100 years ago by Samuel Gilson, this unique material has, since its finding, enjoyed a variety of commercial and industrial applications. Early uses for the product included black automotive paint and beer vat linings. Among its many important uses today are additives for oil well drilling fluids and cements, additives for sand castings for the foundry industry, reinforcing agent for asphalt pavements, and dispersing agent for black inks. Gilsonite is mined and processed in Bonanza, Utah, by two companies, American Gilsonite Company (AGC), an operating division of Chevron Resources, and Ziegler Chemical, a privately held company headquartered in New York.

Jan 1, 1990

By H. Nematollahi

The comminution laws The grindability of the ores or minerals is an important factor that could not be deduced from their mineralogical characteristics (Testut, 1958). Many theories have been proposed to determine the amount of work required in a comminution operation as a function of the nature of material, size and shape of the minerals before and after of comminution. The most important laws are proposed by Rittinger, Kick and Bond. According to Rittinger (1867), the work is directly proportional to the new surfaces produced during the comminution. Kick (1885) believes that the work needed to produce similar modification is proportional to the volume or mass of the material. Bond, during his 25 years of experience and research, reached to the conclusion that on the average the energy required for a known comminution is between the Rittinger's and Kick's laws (Bond, 1952). According to Bond's Third Theory, the work input is proportional to the new crack tip length produced during the particle breakage, and equals the work represented by the product minus that represented by the feed. The work input is given by the following equation: [111W = 1 Owi( FP FF(1)] where W is the The energy input to the mill, (kWh/st); F is the Feed size based on 80% passed, (µm); P is the Product size based on 80% passed, (µm); and W; is the Work Index, (kWh/st) Methods to determine the Bond Work Index Various methods have been proposed by Bond to determine the Work Index. There are some problems with the Standard Bond Grindability Test: •Requiring a special mill. •Requiring a relatively large amount of sample. •Being relatively time consuming and tedious. [ ] During the recent years, numerous attempts have been made to install faster and easier methods to determine the Work Index. A complete description of these methods is presented by Yap et al. (1982). Determining the Bond Work Index by a new size ball mill During the recent years, researchers at the University of Tehran determined the Bond Work Index, using the Anaconda simplified methods by its Denver 305- x 127-mm (12 x 5-in.) laboratory wet ball mill. The equation used to calculate the Work Index for the above mill containing 16.12 kg (35.5 lbs) of steel balls is as follow: [1 _ 1-1W;=0.54x [P [)(2)] In addition, an attempt has been made to determine the Bond Work Index similar to standard Bond ball mill procedure but by a different ball mill, smaller and in consequent portable and less laborious than the Bond ball mill. Method description Just as the standard Bond grindability test, this method is a locked-cycle dry grinding and screening process that is carried out until steady state condition is reached. Test equipment The test is conducted in a special ball mill, called the New Size Ball Mill (NSBM). The mill is scaled down with a coefficient of two-thirds from the standard Bond ball mill. It measures 200 x 200 mm (8- x 8-in.) inside (instead of 300 x 300 mm or 12 x 12 in. in Bond ball mill). Just like the Bond

Jan 1, 1995

By P. M. Lin

This paper presents an overall stabilization method to eliminate the potential of reoccurrence of subsidence over abandoned mine lands. The method considers column grouting at the specific locations inside the subsidence influence areas including the distressed and stress concentration zones instead of grouting' around and beneath the damaged structures. The later method is commonly used for AML subsidence abatement at the present. By using finite element method the conditions of stress distribution in the strata before and after grouting can be calculated. The design of grout pattern includes the location and number of the grouting holes. Based on the calculation, the proposed method significantly reduces the stress concentration, i.e., the potential of reoccurrence of subsidence can be reduced or eliminated. A comparative analysis including number of grouting holes, grout affected area, stress level, and potential of subsidence reoccurrence will also be presented.

Jan 1, 1990

By Rodney R. Krause

In attempting to tell the general public about the coal industry's land reclamation efforts, we have often said, "We're not doing things by the book, because we're still writing it." Like any good catchphrase, the statement is not only striking but true. It is particularly true in the mountains of Appalachia, where the problems of mining; and of reclamation are made more intense by the nature of the terrain. Mining and reclaiming the land "by the book' --which is to say by the methods of contour mining traditionally used in hill country--hasn't worked too well. So a lot of conscientious coal operators and associations are trying new methods--new ways of mining, new machines for seeding and planting, and new species to seed. Not all their experience can be transplanted to other areas, and of course I don't believe that Appalachia is the only place where new methods are being developed. Nevertheless, there's enough action in Appalachia to make a detailed examination rewarding, so let's focus on the hills to see what's new.

Jan 1, 1970

By E. Farrokh

CSM and NTNU models are among the most commonly used models in TBM performance evaluation. Due to increasing application of TBM in different tunneling conditions, modification became necessary for these models. Sensitivity analyses on these two models indicate that both models are very sensitive to machine characteristics. Analyses performed on CSM database for cutter load and penetration rate prediction indicate while the r-square of the CSM model is reasonably high for the predicted cutterload, the r-square value for the penetration is low. In order to increase prediction capability of CSM model for penetration rate the model was reevaluated using non-dimensional analysis and the original database of Colorado school of mines. NTNU model is evaluated using Monte Carlo simulation and regression analysis. The results of analyses indicate that the majority of the variation of the penetration in NTNU model can be explained by only three parameters. This might indicate that the effects of other factors are overshadowed and it is worthy to reevaluate NTNU model using original database and more updated statistical methods to avoid overlapping of different parameters correlations.

Feb 23, 2014

By Kevin B. Doyle

Virtually all industries use sulphur in some form. About half of the world's production is used in the production of fertilizers. Sulphur is produced in one form or another in over sixty countries in the world. The major producing countries, in order of importance, are: U.S.A., Canada, U.S.S.R., Poland, Japan, France, Mexico, and Spain. Canada is the largest exporter of sulphur presently supplying about 30% of the world elemental sulphur export trade. It has held this position since 1968. World sulphur resources are virtually unlimited. Future world competition will come from Iraq and other Middle East countries as well as Central and South America.

Jan 1, 1978

By James C. Cobb

Middle Pennsylvanian (Desmoinesian) coals of certain areas of the Illinois and Forest City Basins contain epigenetic sphalerite and associated minerals in veins, clastic dikes, cleat, and other small-scale structural features. The presence of sphalerite in these coals records information about the geology of coals and coal basins, and represents a potential source for zinc as a byproduct of coal production. Origin of Sphalerite in Coal The origin of sphalerite in coal suggested by Cobb (1) involves sphalerite precipitation from zinc-bearing ?Na-Ca-Cl brines upon contact with sources of sulfur in the coal bed, e.g., pyrite, H2S, and organic sulfur. These brines were essentially at the temperature of the host coals as determined by fluid-inclusion thermometry and vitrinite-reflectance studies. The migration of these brines into coal beds may have been caused by compaction of sediments due to continued sediment loading of the coal basins. Zones of high permeability such as sandstones and the coals themselves presumably acted as conduits for the movement of the brines. The open spaces where sphalerite was deposited resulted from minor deformation associated with differential compaction and cleat formation enhanced by volume shrinkage during coalification.

Jan 1, 1982

By E. DeLilia

For the past 30 years, surface mines have moved toward more highly mechanized, automatic systems that continuously mine overburden and ore to in-crease productivity, lower operating costs and minimize manpower needs. To achieve these goals, mine operators must be involved in every step of the machine procurement process. Several factors are involved in making the machines operate economically and efficiently: ? Prudent engineering. ? Proper planning. ? Realistic feasibility studies. ? Effective specification. ? Thorough training of the mine personnel.

Jan 1, 1995

By Herman Gill, Dani Delaloye, Madelyn Rubin

The Foothill Tunnel is a remote 16-mile-long untreated drinking water tunnel in the San Francisco Public Utilities Commission’s (SFPUC) Hetch Hetchy Water and Power (HHWP) system. The 14-foot horseshoe shaped tunnel, constructed in the 1920s, is lined intermittently with concrete over approximately 53% of its length, with the balance being unlined rock. After detailed planning, in January of 2020 Mott MacDonald and HHWP staff completed a visual inspection and documented the condition of the tunnel with electronic data collection, photographs, and video with audio recording. The result was a comprehensive condition assessment that identified key areas of the tunnel to monitor.

Jun 13, 2021

By M. M. Hajdasinki

A project's rates of return (RORs)1, be it the internal rates return (IRRs) or one of the many IRR surrogates, frequently needs to be approximated. The success and efficiency an ROR- approximation procedure depend on the quality the approximation-initiating parameters, such as bounds or seed values (guesses). The existing approximation procedures commonly use bounds and guesses suggested by intuition rather than supported by mathematical considerations. This paper presents three mathematically founded ROR-bounding and eleven ROR-guessing approaches and examines their suitability by using examples of typical project cash-flowpatterns (CFPs). The calculated bounds and guesses not only improve the approximation efficiency, but also allow the process of the ROR discovery to be automated, thereby making it more convenient and reliable.

Jan 1, 1999

By Thomas A. Palmer

Free cyanide has been successfully determined in ground and surface water by isolation using a microdiffusion technique followed by a pyridine-barbituric acid photometric finish. The determinable free cyanide includes hydrocyanic acid, ionic cyanide, and the cyanide of weak complexes such as cadmium, lead, manganese, and zinc cyanide. Complexes of copper, iron, nickel, and silver are sufficiently strong so the dissociation into free cyanide does not occur at the microdiffusion pH 7. Cyanate, sulfide, and thiocyanate do not interfere. Samples containing as little as 0.005 mg/L are successfully analyzed. The relative standard deviation is <10%. Samples stored at pH >I2 in the dark are stable at least three weeks.

Jan 1, 1981

By Kevin A. Foo, Murray D. Bath, John H. Canterford, Arnaldo Ismay

There is no doubt that the dominant future source of gold will be the so-called refractory ores, especially those with gold in a pyrite/arsenopyrite matrix. Minproc Engineers is taking an active role in establishing detailed design criteria for a number of apparently competing processes. This involves generating a detailed understanding of the metallurgy involved, systematic pilot plant testing, and the application of advanced engineering technologies. This presentation outlines the approach adopted by Minproc as well as the design criteria for several current projects.

Jan 1, 1989

By Adam Bedell, Paul Derby, Brad Crenshaw

Modified contact grouting was introduced almost 15 years ago as a methodology combining traditional contact grouting and consolidation grouting to address groundwater infiltration into hard rock tunnels that utilize cast-in-place concrete as permanent tunnel support. This process has been used on additional tunnels (since initially presented) as a measure to mitigate both groundwater infiltration and exfiltration. During this time, self-sealing grouts have been developed and have been added to the process to further reduce groundwater infiltration that occurs through cracks and discontinuities within the concrete liner itself. This modification is presented and additional results from the grouting process are discussed.

Jun 13, 2021

By Louis M. Perlman

Quantitative methods are, by now, a standard tool of the mining industry, and are commonly used by Research Departments in their evaluation of production methods and schedules, and their associated costs. Indeed, much sophisticated computer work has been devoted to such evaluation of controllable costs and capital requirements. These data are an important input into the project evaluation formula, which is probably the most important single calculation per formed by a mining company, since the result decides whether a particular project is viable. It is instructive to summarize the broad principles of project evaluation, since they are crucial to the remaining sections of this paper. PROJECT EVALUATION The most widely used method of appraising projects is known as Discounted Cash Flow (DCF) method. Two main variants are used; they are known as the &apos;not present value&apos; (NPV) approach and the &apos;internal rate of return&apos; (IRR) approach respectively. The difference between the two is that the former takes the firm&apos;s interest rate as given and uses this knowledge to calculate the present value of the project; whereas the latter calculates the highest interest rate the project could tolerate and still just breaks even. The technique is more simply discussed in terms of the first method (NPV).

Jan 1, 1972

By Louis Schaarschmidt, Helmut Mischo, Ibrahim Alsalamin

In order to store high-level radioactive waste underground, the German repository concept considers clay, crystalline and salt formations as suitable host rock materials (National Citizens’ Oversight Committee, 2024). The current research projects of the Chair Underground Mining Methods at TUBAF (Technical University Bergakademie Freiberg) in nuclear waste repositories mainly focus on storage within salt formations. In this scenario, the high-level radioactive waste is supposed to be packed into specifically designed containers and then transported underground and emplaced in horizontal storage drifts. The residual temperature of the radioactive waste leads to the question if there are optimization possibilities for waste handling, the storage and the long-term emplacement of such high temperature level waste. A deeper understanding of the heat transmission from the container into the host rock might lead both towards possibly shorter surface interim storage times as well as size optimization possibilities of the repository itself. TUBAF has conducted research that successfully proved that an optimized container positioning yields more favorable thermal patterns and can be achieved with conventional mining equipment.

Feb 1, 2025

By W. K. Choi

Using electrochemical techniques it was demonstrated that bioleaching of gold from refractory pyritic ores is a complex phenomenon. Many intermediate electrochemical reactions were found to be involved in the oxidation of pyrite, using cyclic voltammetry and carbon paste-pyrite containing electrode. Furthermore, the oxidation process was controlled by solid-state diffusion as suggested by chronoamperometric and chronopotentiometric measurements. Using the Sand&apos;s approach, the activation energy of solid-state diffusion was found to be = 22.4 kJ. After bioleaching, 96% gold was extracted from the leach resi¬due with a thiourea solution in 1 hour. A generalized model for the mechanism of pyrite oxidation has been presented.

Jan 1, 1990

By John P. Weir

The coal industry is ever changing. This paper discusses some of the problems which must be faced and the projected economic effects. Challenges include a relatively mature technology, a resource base which has deteriorated significantly in some areas, rapidly escalating freight rates, and a constantly changing regulatory environment, wherein reduced sulfur emissions will probably be required.

Jan 1, 1984

By K. Bunney

A high-pressure laboratory elution rig was commissioned to simulate industrial Zadra and AARL elution conditions for the stripping of gold, silver and mercury from loaded activated carbon. It was found that cyanide was essential for the efficient elution of both mercury and silver, while gold was found to elute most effectively in hot, low-ionic strength solutions. Therefore, the standard AARL-type elution, which implements a cyanide soak and water elution, results in a lower recovery of mercury and silver from the carbon. No single set of conditions was found whereby gold, silver and mercury can all be effectively eluted in a single step. However, sequential elution conditions can efficiently recover all metals and provide a potential approach for separating these metals.

Jan 1, 2010