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By Lawrence L. Davis

This paper describes current research by the Bureau of Mines to develop technology for improving efficiency and productivity in metal/ nonmetal mines. The research program addresses a wide variety of problems associated with each of the major categories of mining: underground mining, surface mining, in situ mining, and premining investigations. An overview of the Bureau's research activities is given with emphasis on underground mining. In particular, two innovative and promising concepts currently under development are described: a unique shaft sinking system that uses an impact hammer for rock fragmentation, and a low-profile, portable crusher for underground hard-rock applications.

Jan 1, 1979

By Neil S. Fishman

Tabular uranium ore in the Grants uranium region, New Mexico, occurs as tabular layers of a urano-organic mixture suspended within host sandstones of the Morrison Formation. The intimate urano-organic association points to the organic material as the main ore control. Petrographic evidence indicates that the organic material was postdepositionally introduced into the host sandstone, probably as humic acids; however, the mechanism by which these acids precipitated from solution remains uncertain. A model, the cation scavenging model, is proposed in this paper to explain humic acid precipitation. The model, supported by evidence from regional alteration studies of the host sandstones, proposes that cations responsible for humic acid precipitation were scavenged from framework grains which altered during passage of the humic-rich fluids through the host sandstone. This process, coupled with the affinity of organic molecules for each other, caused flocculation of humic acids into tabular zones. The precipitated humic substances then continued to concentrate uranium to form the orebodies. The cation scavenging model requires only one solution, the humic-bearing solution, in the precipitation process. All cations necessary for humic acid precipitation originated in the host sandstones. This model contrasts with a previously proposed model--the brine interface or two solution hypothesis--in which it was proposed that a cation-rich brine introduced into the host sandstones provided the cations necessary for humic acid precipitation. The brine hypothesis has several drawbacks, one of which is unrealistic hydrologic reconstructions necessary to accommodate mineralization at various stratigraphic horizons in the Morrison Formation. Moreover, no mineralogic evidence exists to suggest a brine occupied the host sandstones at the time of mineralization. The proposed cation scavenging model for humic acid precipitation not only readily accounts for humic acid precipitation, but also is consistent with geologic observations and regional alteration studies.

Jan 1, 2013

By Ismail Adeniyi Okewale, Hendrik Grobler

Significant factors believed to be responsible for tailings dam failure which can lead to loss of lives, destruction of properties and assets or damage to the environment are the mechanics of material characteristics and static liquefaction. It is therefore essential to understand the tendency for the likely occurrence of liquefaction in tailings dam as well as mechanics behind the behaviour of this tailing materials (inevitable products of ore mining, mineral and metallurgical processes). This study aims to present the mechanical behaviour and susceptibility to liquefaction of a gold tailings sample. Series of oedometer tests were conducted to determine the compression behaviour and the possibility of transitional behaviour or not. Index and physical tests were conducted to determine engineering grading descriptors which was directly linked to compression behaviour and comparisons made with other tailings. Microstructure was studied to understand the effects of fabric on the behaviour of samples and the chemical composition and mineralogy were also investigated. The compression paths slowly converge and the gold tailings might be said to be less transitional. The gold tailing is less dependent on initial state. The loosest gold tailing is more susceptible to liquefaction and compared to other gold tailings, this sample is less susceptible to liquefaction.

Apr 19, 2024

By Frank C. Schora

The Institute of Gas Technology for many years has dedicated a large portion of its research effort to the development of a practical solid-fuel-based gasification process to produce a synthetic natural gas equivalent. The work is being done to prepare for the day when supplemental gas will be needed. This program, initially supported by the American Gas Association, and now by both the Department of Interior's Office of Coal Research and the American Gas Association, has developed the IGT Hydrogasification Process. This process, now entering the pilot plant stage, is based on the high-temperature, high- pressure hydrogenation of coal with a hydrogen-steam bearing gas. Product gas from this step is cleaned and catalytically methanated to produce a high-Btu gas. Estimated production costs indicate the process will be competitive with natural gas in certain areas of the country when required.

Jan 1, 1969

By Glenn A. Squibb

An example of market development is described. The market in rail-lake movement of coal is vital to a rail carrier because of its location. This market is threatened by nuclear and other competing fuel sources and by depressed all-rail unit train rates, The first step to develop the rail-lake transportation market consists of rate adjustments and tariff changes to force tighter scheduling of mines, railroad, port and boats, and thus reduce cost. The second step provides a surge pile at the port to eliminate most of the seasonal disadvantage of rail-lake movement and reduce car detention at the port to almost zero.

Jan 1, 1966

By Ditend Tesh, Mallikarjun Pillalamarry, Nikowa Namate, Harmony K. Musiyarira

Many reports have been written about the issues surrounding small scale miners’ challenges in Namibia; yet little has been done to address these challenges. There has been a fragmented approach to address these challenges. Various government arms and donor organizations have utilized piece meal methods in the past in trying to make improvements on the productivities across the sector, but with no meaningful success. This has led to the design and implementation of inappropriate technologies and support services for the sector. The structures of many of the semi-precious stones mining businesses are informal, with very little royalties received by the government. Miners often work informally or illegally and they fear government interference and they distrust outsiders, resulting in them withholding production information. The presence of small scale miners is quite often associated with major challenges, including poor safety and environmental management standards, the spread of communicable diseases and poor working conditions. The majority of the miners employ uncontrolled extraction techniques which damage the crystals and mineral specimens, resulting in intermediate and final products of low quality along with high wastage at the extraction stage. The vision of the Namibian government is to expand the range and value of semi-precious stones and jewelry products processed within Namibia, while curbing illicit flows of raw stones. This will simultaneously secure maximum benefit for the country. This study investigated the interventions aimed at making the small scale mining sector in Namibia sustainable. A baseline study was conducted to analyze the current situation and characterize the industry, including a SWOT analysis. Information was collected through questionnaires, interviews, consultative meetings, field visits and workshops in order to profile the sector. The baseline study results were used in developing interventions for improving artisanal and small scale mining operations. The main challenges for the Namibian semi-precious sector were identified as: factual information about raw material resources and its beneficiation are insufficient or not available, lack of skills, lack of education and access to finances, rudimentary exploration and mining practices, trading and logistics that are not functioning effectively and inadequate sector governance. One key finding of this study was that Namibia is not benefiting through value addition due partly to illicit flows of the uncut stones and to the fact that lapidary is not much pronounced to a greater extent. The following strategic interventions were identified as key in ensuring the sustainability of the small mining sector in Namibia: conducting geological assessment to identify new deposits and quantify the existing ones, improving exploration and mining practices, investing in education and training, creating an enabling environment and improving the sector governance and strengthening the sector organization and supporting the infrastructure.

Jan 1, 2017

By E. C. Skinner

As the program says -we'll he talking about the expectations of the Management of an Industrial Mineral enterprise relative to the activities of geologists engaged in that enterprise. Industrial Minerals is such a large industry both in tons produced and in value of product -and of such diversity and complexity of participating enterprises, minerals and products that I doubt if anyone person can speak for the entire industry as to the expectations of management with respect to the geologist. I'm sure there are major differences in emphasis between segments of management as to the relative importance of the different aspects of the geologists' role in the scheme of things. However, we will try to generalize concerning what we consider to be important factors and to be more specific perhaps of some of the factors with which we have had direct assessable experience.

Jan 1, 1972

By H. F. King

In 1982, the result of a 3-year study was published as "A Guide to the Understanding of Ore Reserve Estimation". The principal conclusions were that computation formed only part, and perhaps not the most important part, of an estimate and that the estimate should recognize that geological, mining engineering and metallurgical judgements formed an essential part of the eventual result. Subsequent expectation/realization studies of several mines have produced case histories which form the principal basis of the paper. These imply that geology is even a larger factor than thought earlier.

Jan 1, 1985

By D. R. McMullin

The purpose of this paper is to provide a method for mine planners and engineers to evaluate on a conceptual basis if a shaft or a ramp is most suited for their particular underground access requirements. Mine planners and engineers are often raced with the decision of choosing which method of underground access is best suited for their particular requirement. Underground access can be provided by a shaft, ramp, adit, or slope for either exploration and/or actual production operations. This paper will focus on the construction cost and schedule differences between sinking a shaft and excavating a ramp which are currently the most typical access alternatives used in the western United States. It would be wrong to state that one method is superior to the other in every case. There are many variables to be addressed, and the degree of sensitivity of each of them will eventually dictate which method is the most suited to the particular circumstances. This paper compares the construction cost and schedule or sinking a shaft to excavating a ramp at different depths given different ground and hydrological conditions. This comparison provides mine planners with "rules or thumb" that may be applied to the access selection process.

Jan 1, 1994

By L. M. English, Y. J. Wang

When plotted as head vs. volume, fan curves start high and decrease with increasing volume, while mine head curves start low and rise with increasing volume. Their intersection is the system operating point. However, as every ventilation instructor knows, the fact that head loss is a negative number (debit) and fan head is an energy addition (credit) is often a stumbling block to student or audience comprehension since the curves seem to reflect the opposite. It is possible to use the intuitively correct curves- pressure losses as negative values and energy additions as positive values - and still obtain the correct operating point. Adding the two curves produces a third curve that intersects the x-axis at the operating point, the point at which the fan energy input exactly matches air circulation energy loss. Using this technique also makes it easier to account for outside influences on the system, such as natural ventilating pressure. With the standard approach, it is quite easy to add or subtract such influences to the wrong curve. This approach can be extended to the graphical solution of any series/parallel ventilation network. The results are the same, and the approach is logically consistent and less confusing.

Jan 1, 1999

By Valois R. Shea-Albin

Increasing pressure from State and Federal agencies to mitigate mining-induced subsidence damage to overlying structures has presented a unique problem to the coal industry in the western United States. Because sandstone escarpments are an environmental issue, millions of tons of coal reserves that underlie these escarpments risk being classified as unminable by regulatory agencies. At this time, the effect of subsidence on escarpments has not been well documented or characterized. The Bureau of Mines is using numerical modeling techniques to analyze escarpment response to longwall mining. Two- and three-dimensional finite element models have been constructed for a study area near Price, Utah, where longwall panels were mined near an escarpment. This status report includes preliminary results showing that the pattern of subsidence surrounding the escarpment can be simulated through numerical modeling. Models that include such structural details as joint and fracture patterns will better simulate subsidence patterns .and magnitude. By locating longwall panels strategically in relation to the escarpment, stability may be preserved throughout the mining process. Numerical modeling provides a method to analyze relatively quickly the effects of longwall panel location and resulting subsidence on escarpment stability. The goal is to provide a relatively accurate predictive tool for mine planning to determine if escarpment stability can be maintained while maximizing extraction of the coal reserves.

Jan 1, 1986

By Paul S. Murphy, Eric W. Oehrke

INTRODUCTION The global market for sulphur has experienced dramatic structural shifts during the past 10-15 years. After a number of years of dominance as sulphur suppliers, the world's Frasch producers were confronted with large increases in nondiscretionary sulphur production from sour crude oil and gas, while escalating energy and exploration costs reduced the economic incentives to replace dwindling sulphur reserves. Sulphur demand also experienced substantial growth, but the majority of this increase was filled by nondiscretionary production. The result was essentially flat demand for Frasch sulphur during this period. This paper briefly summarizes Freeport Sulphur Company's outlook for global supply and demand for sulphur through the year 2000, and examines in more detail the history and anticipated shifts in trade patterns. World trade in elemental sulphur (brimstone), despite year-to-year fluctuations, has been on an upward trend in recent years, and should continue to grow through the end of this century. The type (discretionary vs. nondiscretionary) and location of forecast sulphur supply sources has potentially broad implications for the world's Frasch producers, as they compete in a world market which is increasingly supplied by non-discretionary production. SULPHUR DEMAND Sulphur is a versatile and essential element used in a wide variety of manufacturing processes. Almost 90% of world sulphur consumption is in the form of sulphuric acid. The relatively low cost, ready availability, and physical and chemical properties of sulphuric acid make it the most economical acid for a number of chemical processes. Although sulphur is used in the manufacture of many products, the largest consumer by far is the phosphate fertilizer industry. The majority of sulphur demand growth over the past 30 years has occurred in this area, and today it accounts for nearly 65% of global sulphur consumption in all forms. Due to the relative importance of phosphate fertilizers, sulphur demand is typically discussed in terms of fertilizer and non-fertilizer (or industrial) uses, and this approach will be followed here. We at Freeport believe that global consumption of phosphate fertilizers should grow at an average annual rate of about 3.5% through the year 2000, which is roughly equal to the growth rate experienced during the past ten years. The basic assumption underlying this forecast is that world population will continue to grow significantly, while the total acres of cropland will grow only slightly. Therefore, in order to feed a growing population, higher crop yields will be necessary, which in turn will require the increasing use of fertilizers. This expected growth in phosphate consumption will, without doubt, fluctuate from year to year, and we Frasch producers have painful memories of the large dip in demand during 1982-83. However, we believe that the fundamentals for growth are very good, and that future demand will move back onto the historical trend line. In the recent recession the use of sulphur in the non-fertilizer or industrial sector dropped sharply, and it now appears that future growth will not return to the old trend line. Most of the non-fertilizer uses of sulphur and sulphuric acid involve older industries which are very mature, such as oil refining, steel, pulp and paper, pigments, etc. The use of sulphur in some of these industries is expected to exhibit little or possibly even negative

Jan 1, 1986

By T. S. Golosinski

Typical dragline rigging includes several sets of ropes: hoist ropes, drag ropes, dump ropes and boom suspension ropes. The drag and hoist ropes contribute most to the dragline operating cost, and significantly influence dragline productive time. Both work in very difficult conditions and wear out rapidly. As a result frequent rope changes are required at a substantial cost and time loss to the operation. Although performance of rigging has a profound impact on dragline performance, there are no industry-wide standards related to its selection, operation and maintenance. Little information on the subject is available and the practice differs widely throughout the industry. The life of drag and hoist ropes depends on: (1) rope construction, which should closely match requirements of the specific application, (2) correct definition and application of the rope discard criteria, so that full advantage of the rope can be taken without endangering safety of operation, and (3) rope operating conditions and its maintenance. The study presented in this paper was intended to address the above points, based on a survey and assessment of the present industry practice.

Jan 1, 1993

By D. Denton, C. Peppin, D. Tesarik, D. Bayer, J. B. Seymour

Hecla Mining Company and NIOSH cooperated in a study to document the safety of rock support supplied by reinforced cemented paste backfill at the Lucky Friday Mine. Data are presented on backfill modulus values from laboratory tests and compared with modulus values from in-mine wall closure on the backfill. It is theorized that a compressive zone is created in the backfill between the upper and lower bearing plates on the reinforcing bolts, and that the backfill remains stable as long as the compressive zones from adjacent bolts overlap.

Jan 1, 2001

By M. L. Matt

The Pittsburgh Safety and Health Technology Center of the Mine Safety and Health Administration has developed the Mine Emergency Responsiveness Development (MERD) program to improve the reaction and response of mine personnel in mine emergency situations. The MERD program simulates problems that may be encountered in underground mine fires, underground mine explosions or surface mine accidents. Since its inception in 1982, the MERD program has been presented to MSHA, Industry, Labor and State Government Personnel. The program is extremely versatile and is easily adapted to suit various training requirements. It gives the participants the opportunity to experience some of the emotions, frustrations and successes of a mine emergency in a controlled environment without having to be involved in one. Past participants have indicated that this training has better prepared them in actual emergency situations through increased awareness and advanced preparation of plans and resources. In 1992, a Mine Simulation Laboratory, which simulates a coal mine and metal/nonmetal mine, was built to improve training for mine emergencies and prevention and fighting of mine fires. This facility has been included in the MERD Program to provide realistic and practical training for mine rescue teams and MERD participants in advanced mine emergency operations. This paper presents an overview of the MERD program.

Jan 1, 1993

By R. Venkataramani

Even though the mining industry in 1966 produced more ore than ever before, current extraction rates are only a fraction of what is expected in the later years of the twentieth century. Nearly 90% of all metals and-mineral products consumed last year was recovered by open-pit mining. This has placed great pressure on this segment of the industry which has, consequently, resulted in some spectacular developments. With increasing size of projects, the need for increased sophistication of engineering, planning, management and administration of modern mining installations has never become more apparent. The design of complete systems for the mine and plant that fit the mould of today's business and social environments is undergoing an evolutionary process. Traditional concepts in mine development and operations are being sidestepped in favor of new ideas and principles. As the overburden thickness increases, materials handling presents a major problem to mining companies, especially those concerned with the mass production of ore and waste from low-grade deposits. The profit margin here is likely to be significantly less as to take chances with capital investment. 1 Constant efforts are needed to improve upon productivity if the ore is to be economically mined.

Jan 1, 1970

By A. M. Gaudin

The recent study by R. M. Hays(l) prompted the study summarized in this paper. In his Interesting paper, Mr. Hays shows fine results to be attainable by a relatively complex flowsheet on a semi-taconite, a manifestly difficult ore to treat. We obtained a semi -taconite from Minnesota, and treated this sample by wet magnetic separation alone. The device in which the separation was accomplished is the standard pilot-plant, laboratory separator in use at Magnetic Engineering Associates' laboratory (MEA) in Cambridge, Massachusetts. It consists of a cylindrical space which can be magnetized by turning on the magnet of the separator. In this cylindrical space, there is a canister which provides the special configuration of the magnetic field and magnetic field gradients that MEA considers to be required. The ore pulp is made to flow through the canister while the current is on. A portion of the pulp is retained in the canister, and the rest is evolved as a non-magnetic fraction. The laboratory device is cyclic, but it accurately predicts the results obtainable by an Industrial unit of either cyclic or continuous type (moving matrix). The ore tested was 99.5°%o -325 mesh, and approximately 75% -500 mesh. The concentrate from this ore was, therefore, eminently suitable for pelletizing. In passing the ore through the magnet, we had the choice of repeatedly passing the concentrate from the first step through the operation, or of repeatedly passing the non-magnetics. In our experiments, the first method was clearly superior from the stand¬point of the cleanliness of concentrate. Of the many tests which we have made, we think that we have to retain two which

Jan 1, 1971

By Z. Konstantinovic, M. Ahrens

Due to the large installed electrical power and the large number of electric drives in minerals and mining plants power factor compensation and harmonic filtering has always been an important issue. For the design of harmonic filter and power factor compensation installations several approaches can be taken. The paper describes different concepts and their advantages and analyzes special requirements and design considerations for minerals and mining plants. It also highlights areas where problems can occur and which points need to be addressed carefully. Optimized designs and solutions are discussed in case studies and the resulting energy savings and benefits for the plant operation are shown.

Jan 1, 2007

By A. J. Wainwright

The Coffee Creek lode gold discoveries are located in the White Gold district (Dawson Range), west-central Yukon, 130 km south of Dawson City and 30 km south of the Golden Saddle gold deposit (Figure 1). Extensive structurally-controlled gold mineralization has been discovered during the 2010 and 2011 exploration drilling campaigns, highlighting this part of the Dawson Range as a significant emerging gold district. [ ] In this contribution we review the geological framework and describe the mineralization styles and metal signatures observed to date on the Coffee project. The main Coffee area is underlain by a 15 km by 4 km geochemical footprint, characterized by discrete linear gold-in-soil anomalies that correspond to various mineralized corridors. Of several mineralized areas tested in the past two drill seasons by diamond core and reverse-circulation (RC) drilling, we focus on the Supremo, Double Double, Latte and Kona zones; areas with the most information obtained from drilling thus far (Table 1; Figure 2).

Jan 1, 2012

By R. R. Hall

Tests were conducted to assess the potential of column flotation for beneficiation of a talc ore from Montana. This ere contained approximately 80% talc, with the gangue comprised mainly of chlorite, silica, and dolomite. A tributylamine, MIBC, and sodium silicate reagent suite proved effective for talc flotation. Rougher-cleaner column flotation in a continuous open-circuit produced a final talc concentrate which contained 0.90% Al2O3. 0.17% CaO, and 1.28% Fe2O3. These analyses represented impurity rejections of 77, 85, and 65%, respectively. Weight recovery for this open-circuit was 52%; however, weight recovery was estimated to be 75% with cleaner tailings recycle. Results from this investigation show that column flotation is a viable means for beneficiating talc.

Jan 1, 1990