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By Y. H. C. Wang

A detailed study of carrier flotation of kaolin clay using calcite showed the major beneficiation mechanism to be enhanced aggregation between anatase and calcite under intense agitation conditions. In order to develop an understanding of this selective aggregation, surface charge characteristics of kaolinite, anatase and calcite were studied under simulated flotation conditions. Zeta potential of all these minerals tended towards a constant negative value in ole- ate solutions under certain conditions possibly due to adsorption or precipitation of oleate on them. However, whereas the zeta potential of anatase in the oleate solutions was not influenced by the agitation level, that of kaolinite was found to be strongly dependent on the agitation intensity. The effect of oleate on zeta potential of kaolinite was reduced by an increase in agitation intensity. It is suggested that oleate is much more firmly bound to the surface of the anatase and that this preferential attachment is responsible for the enhanced selective aggregation of the anatase with calcite. Agitation level plays a major role in carrier flotation since intense agitation is considered to en- hance both the chemisorption of oleate on anatase and preferential detachment of calcium oleate precipitate from the kaolinite surface, all of this producing a large difference in the surface properties of anatase and kaolinite, and hence in their tendency to aggregate with calcite.

Jan 1, 1981

By C. Sunderman, R. Jacksha

"Mine monitoring through various sensors is a vital component of successful miner safety and health programs. Data from environmental, geotechnical, infrastructure, and other types of sensors are increasingly being used to discover and mitigate health and safety concerns in underground mines. In many smaller underground mines, as well as in new development headings of larger underground mines, leaky feeder communication systems may be the only available means to transport crucial monitoring data. In addition, data transport is increasingly being delivered using Internet Protocol (IP) while older forms of serial communication are being retired. This paper presents the selection, configuration, and testing methodologies that were employed by researchers from the National Institute for Occupational Safety and Health (NIOSH) to integrate commercially available land mobile data radios into an existing leaky feeder communication system to provide Internet Protocol data transport. INTRODUCTION To enhance the health and safety of their mining workforce, mine owners and operators are increasingly installing environmental monitoring and control systems in underground mines. Real-time, mine-wide monitoring is becoming a reality with the implementation of the Industrial Internet of Things (IIoT) into the underground mining industry [1]. However, not all underground mines, especially smaller mines and new development headings in larger mines, have the information technology (IT) infrastructure in place to handle the data transport requirements for the newer IP-based technologies that are part of IIoT. This was the case with a mine in the Western United States; it lacked the infrastructure to perform critical monitoring in remote headings. The mine partnered with the U.S. National Institute for Occupational Safety and Health’s (NIOSH’s) Spokane Mining Research Division (SMRD) to develop and evaluate a cost-effective solution for real-time monitoring of geotechnical conditions in relatively remote sections of the mine. This paper describes SMRD’s solution to leverage the mine’s existing leaky feeder system to achieve IP data transport using commercially available land mobile data radios. DATA RADIO SELECTION The primary selection criteria for the data radios were network data format, modulation type, and radio channel spacing. The network data format decided upon was Internet Protocol. This format allowed for straightforward integration between the IP-enabled data acquisition system located in a remote heading and the network switch located in the control room. It also eliminated the added complexity of additional network hardware such as Ethernet to Serial converters. IP additionally provided a direct path to integration into higher bandwidth networks, such as fiber optic, should they become available."

Jan 1, 2018

By John J. Sammarco, Alan G. Mayton, Elaine N. Rubinstein

Researchers from the U.S. National Institute for Occupational Safety and Health (NIOSH) developed the Saturn light that significantly improves illumination for roof-bolting machine operators while reducing glare. The existing roof-bolter lighting was the baseline and was compared to the Saturn at 100, 75 and 50 percent intensities. Discomfort glare and disability glare were measured by the De Boer rating scale and the Mars Letter Contrast sensitivity test, respectively. Thirty study participants were tested. Discomfort glare was reduced at least three levels with the Saturn luminaire. Visibility levels were four to 6.5 times better with the Saturn than with the baseline. The Saturn design is freely available for commercialization.

By Robert A. Westman

The INRED process has been developed step by step by Boliden since 1972 at MEFOS, the Foundation for Metallurgical Research, at Lulea in Sweden. The demonstration - plant is number five in this series. The purpose of this plant, which has a nominal capacity of 60,000 tonnes per year of hot metal is to: 1) prove the process on a sufficiently large scale to provide the basis for construction of production plants, 2) test various kinds of raw materials on behalf of licensees, 3) train operators of the first production plant, 4) develop the process further for special applications.

Jan 1, 1983

By Henry E. Reed

This presentation is about a small company, Industrial Mineral Products, that was formed in 1972 with one product and one customer and by a series of value-added changes avoided disaster and increased sales many times over. The principal of the company stopped by my office in Seattle looking for industrial mineral opportunities in the Northwest. We got together and went through all the minerals in Ladoo's "Industrial Minerals" from Abrasives to Zircon to see if we could find something available on the vast holdings of the Burlington Northern. At that time one of our lessees was operating a silica sand mine near Ravensdale, Washington and indicated that he might be interested in selling out. This sounded interesting to my client and within two weeks the transaction was completed.

Jan 1, 1990

By B. Das

Most coals are susceptible to spontaneous heating which in turn creates problem to mining, storage and transportation of coal. It is impossible in actual practice o eliminate spontaneous heating but spontaneous combustion can effecively be controlled through a clear understanding of its mechanism and the factors affecting it. There are altogether six stages in the process of spontaneous combustion. This includes the water adsorption stage and six oxidation stages: chemi-sorption (upto 70°C), decomposition of peroxygens (70°C-150°C), oxy-coal formation (150°C-230°C), combustion initiation (230°C) and active combustion (> 230°C). Heat is produced in all these stages. On the other hand heat is also dissipated so that some equilibrium temperature is reached. If this temperature exceeds a certain critical value (generally about 70°C), coal oxidation may advance to spontaneous combustion. The major factors influencing spontaneous combustion of coal are: coal rank, maceral composition,, water, mineral matter, joints and fissures, seam depth and thickness, mine Layout, method of ventilation, etc. Susceptibility is high for low rank coals and generally decreases with increase in rank. Of the macerals, the exinites are generally most susceptible, the inertinites least and the vitrinites somewhere in between. Water plays a major role on the spontaneous heating of coal, assisting in someways and inhibiting in other. Unrecovered coal in the gob (generally in thick seams) is a major source of fire hazards and this is specially important in shallow mine. Proper design of mine ventilation system can substantially reduce the risk of mine fire. Panel layout and load transfer can affect the development of induced cracks which in turn influence spontaneous heating. Finally, the difference between the spontaneous heating of coal in a seam and that in storage or transportation is mainly due to the change in moistured content, air circulation through the coal and coal fragmentation. These aspects have been analyzed in this paper with a view o reducing the risk of spontaneous combustion.

Jan 1, 1986

By Khosrow Badiozamani

Operating mines in Wyoming and Montana, which are generally characterized by shallow overburden and thick coal seams, are faced with reclamation problems which are unique to this area. Unlike the eastern or midwestern mines, removal of thick coal seams and lack of sufficient overburden creates overburden deficiencies that require careful evaluation prior to mining to insure compliance with regulatory requirements. Computer models and computer graphics can assist in such evaluation where appropriate alternatives can be selected which satisfies both the regulatory requirements and minimizes cost. This paper presents one such model used in evaluation of backfill requirements for restoration of surface and ground water regimes, restoration of mined-out areas to the approximate original contour, and the blending of the mined-out areas to the surrounding topography.

Jan 1, 1981

By Jamal Rostami, Alireza Salimi, Christian Moormann

"Rock mass classification systems are often applied in many empirical design practices in rock engineering, some contrasting with the original intent and applications of these classification systems, for example, estimation of TBM performance in various ground conditions. While accurate estimation of machine performance is significantly impacted by rock mass properties, parameters used in many of the existing classifications are more related to ground support design and not rock mass boreablity. The results of many investigations on this issue have shown a weak correlation between TBM rate of penetration and rock mass classification. This limitation can be overcome by fine tuning the rock mass classification input parameters to represent influence of rock mass properties on TBM performance as has been the objective of RME or QTBM. This paper will offer an overview of the impact of rock mass on TBM performance and introduces an empirical equation for predicting performance of rock TBMs based on rock mass classification. The results of the preliminary analysis of a new model has revealed that the use of the proposed system can offer a reasonable accuracy for estimation of TBM performance in various rock masses. 1. INTRODUCTION Hard rock tunnel boring has become more or less the standard method of tunneling for tunnels of various sizes with lengths over 1.5–2 km. Estimating the performance of TBM is a vital phase in tunnel design, and for the choice of the most appropriate excavation machine. During the past three decades, numerous TBM performance prediction models for evaluation of TBM rate of penetration and advance been proposed. In brief, all the TBM performance prediction models can be divided into two distinguished approaches, namely theoretical and empirical ones (Rostami et al., 1996). The most common and recent works on this topic are summarized in Table 1. Currently, two models including Colorado School of Mines or CSM (Rostami and Ozdemir, 1993; Rostami, 1997) and Norwegian University of Science and Technology or NTNU (Blindheim, 1979; Bruland, 1998) models are the most recognized TBM performance prediction and prognosis models in use around the world."

Jan 1, 2016

By U. Cetin

The Nevada Test Site is located approximately 65 miles northwest of Las Vegas, NY. The site was primarily used by the Department of Energy for the field testing of nuclear weapons and contaminated by several million cubic feet of low-level radioactive wastes, heavy metals, volatile and non-volatile organics, and explosive materials. Leaching and transportation of these contaminants are creating severe environmental problems. The purpose of this study is to examine pozzolan, a natural alumina-silicate mineral, as a possible replacement of the existing impermeable barriers (clays). In the first phase of this study, radionuclide sorption characteristics of pozzolan were investigated. This paper will present the results of the sorption tests for the target radionuclides.

Jan 1, 1998

By John P. Anderle

A tectonically disturbed sequence of Mississippian age evaporites expressing a 5 milligal negative gravity anomaly near Sussex in southeastern New Brunswick, Canada, was investigated by a program of drilling, geologic and geophysical work over the past 27 months. Seventeen of twenty-one drill holes have penetrated 10 to 140 feet of potash mineralization in a salt sequence underlying 2 000 to 3 000 feet of arenaceous, conformable red beds, also of Mississippian age. Bromine and borate studies, lithological characteristics and geophysics, have facilitated improved understanding of the salt structure. The salt sequence has been affected by f1owage which has resulted in both major and minor folding. In the more disturbed areas, the potash interval was extensively subterraneally eroded at the upper anhydrite-salt contact.

Jan 1, 1978

By N-h. Mao

We applied kriging (geostatistics) to interpret the structure of basement rock in Yucca Flat, NTS from borehole data. The estimation error for 118 data is 81 m comparable with those based on both gravity and borehole data. Using digitized topographic data, we tested the kriging results and found that the model validation process (Thomas option) on data gave a fair representation of the overall uncertainty of the kriged values.

Jan 1, 1985

By J. D. Noll, J. A. Organiscak, A. B. Cecala

Significant strides have been made in optimizing the design of filtration and pressurization systems used on the enclosed cabs of mobile mining equipment to reduce respirable dust and provide the best air quality to the equipment operators. Considering all of the advances made in this area, one aspect that still needed to be evaluated was a comparison of the efficiencies of the different filters used in these systems. As high-efficiency particulate arrestance (HEPA) filters provide the highest filtering efficiency, the general assumption would be that they would also provide the greatest level of protection to workers. Researchers for the U.S. National Institute for Occupational Safety and Health (NIOSH) speculated, based upon a previous laboratory study, that filters with minimum efficiency reporting value, or MERV rating, of 16 may be a more appropriate choice than HEPA filters in most cases for the mining industry. A study was therefore performed comparing HEPA and MERV 16 filters on two kinds of underground limestone mining equipment, a roof bolter and a face drill, to evaluate this theory. Testing showed that, at the 95-percent confidence level, there was no statistical difference between the efficiencies of the two types of filters on the two kinds of mining equipment. As the MERV 16 filters were less restrictive, provided greater airflow and cab pressurization, cost less and required less-frequent replacement than the HEPA filters, the MERV 16 filters were concluded to be the optimal choice for both the roof bolter and the face drill in this comparative analysis case study. Another key finding of this study is the substantial improvement in the effectiveness of filtration and pressurization systems when using a final filter design.

Aug 1, 2016

By A. J. Lewis, P. J. Hutcheson, M. E. Robertson, P. A. Moir, K. M. Barfoot

With the content of gold and platinum in the vast majority of ore deposits typically averaging 6 parts per million and less, the accurate and precise measurement of these metals in samples of ore and mining process streams has proven very difficult to achieve by modem spectroscopic analytical techniques. Largely because no other technique has proven suitable, the basic fire assay process has become the accepted international standard for these metals. Fire assay, however, suffers a number of disadvan­tages in the modem, competitive, high technology, and increas­ingly environmentally aware world. It is a labour intensive technique that is difficult to automate, and requires high levels of skill to ensure accuracy and consistency of results. Potentially hazardous chemical reagents are employed, of which, lead, in particular, can be a serious source of contamination to both personnel and the environment if not effectively controlled. Other dangerous elements, such as mercury and arsenic, liberated in high energy furnace operations, are further sources of possible health and pollution hazards. n contrast, the energy dispersive K X-ray fluorescence (K­XRF) technique devised by K X Technology Ltd overcomes many of the technical constraints of conventional low energy X­ray analysis, and has the potential to revolutionise assay opera­tions in precious metal mining. The technology is simply automated, requires basic operator skills, uses no chemicals, consumes less than 20kW, and is capable of detecting gold and platinum to an accuracy of O .1 parts per million by mass. The new third generation design of AZTEC laboratory instrument, released in 1994, is the result of significant technical development. Capable of analysing over 1200 samples per day, and developed primarily for grade control sampling, its applica­tions have spread to gold ore accounting from on-line conveyor belt sampling; screening of exploration samples; measurement of gold in carbon granules for Carbon-in-Pulp process control; and for conducting rapid checks to support key managemen decisions. The economic, rapid, and non destructive analysis ofup to 80g of ore for large numbers of samples, reduces sampling and sub-sampling errors, and provides improved grade estimates for ore bodies. When interfaced to a LIMS, laboratory automation and cost-savings can be further enhanced. The AZTEC design is also being modified for the analysis of platinum. The GOLDSTREAM on-line analysis system is an important new application of K-XRF to the continuous monitoring of process streams in gold ( or platinum) plants and mills. Integrat­ing the technologies of K-XRF to measure total gold, and dissolved gold spectroscopy to measure gold in solution, the insoluble fraction of gold can be deduced, and the effectiveness of the extraction process determined. Slurries are sampled automatically from selected points of the plant and pumped to the system for analysis. The information produced forms the basis for plant control and optimisation.

Jan 1, 1995

By Liming Yuan, Wei Tang, RICHARD THOMAS, JOHN SOLES, DAVOOD BAHRAMI

Mine equipment fires remain as one of the most concerning safety issues in the mining industry, and most equipment fires were caused by hot surface ignitions. Detailed experimental investigations were conducted at the National Institute for Occupational Safety and Health’s (NIOSH) Pittsburgh Mining Research Division on hot surface ignition of liquid fuels under ventilation in a mining environment. Three types of metal surface materials (stainless steel, cast iron and carbon steel), three types of liquids (diesel fuel, hydraulic fluid and engine oil) and four air ventilation speeds (0, 0.5, 1.5 and 3 m/s) were used to study the hot surface ignition probability under these conditions. Visual observation and thermocouples attached on the metal surface were used to indicate the hot surface ignition from the measured temperatures. Results show that the type of metal has a noticeable effect on the hot surface ignition, while ventilation speed has a mixed influence on ignition. Different types of liquid fuels also show different ranges of ignition temperatures. Results from this work can be used to help understand equipment mine fires and develop mitigation strategies.

Oct 1, 2022

By Neil Hillhouse

The Porgera gold district, like many other large gold deposits, has a long history of awareness, but only in the last five years has a geologic understanding of the district permitted the discovery of economically attractive gold reserves. The following sequence of events highlights the various significant steps in the evolution of the discovery process. The history of the district goes back about 50 years, and for several decades it was known only for its placer gold. Gradually, as gold became a more interesting metal, more and more attention was centered on the district. The sequence of events does not overstate the problems caused by isolation and climate, but the reader can imagine the difficulties inherent in such an area.

Jan 1, 1990

By A. Sinha, C. Sawmliana, P. Pal Roy

Using the newly developed and permitted explosive Pentadyne-HP (Gulf Oil Corporation Ltd., Hyderabad), the Blasting Department of the Central Institute of Mining and Fuel Research, Dhanbad experimented at the GDK-5 Incline, RG-1 Area of the Singareni Collieries Company Ltd. (SCCL) to establish one modified angular cut blasting pattern as an alternative to conventional solid blasting in India to obtain longer pull, as well as to achieve at least 40 t of coal in a single blast round for the deployment of diesel load-haul-dump units at the face. This permitted explosive satisfied the statutory requirements of incendivity characteristics applicable to P5 explosives of the regulatory agency Directorate General of Mines Safety (DGMS) of India. The present paper summarizes the development of this new blasting pattern and its possible use in Indian coal mines.

Jan 1, 2010

The initiation of a panel cave is an extremely important and infrequent event in the life of a large underground caving operation. A new cave was initiated at the Henderson Mine in 1991, 15 years after its first cave had been developed in 1976. The original cave was started after a half billion dollars had been invested in the development of the mine, mill and 23 km haulage system. Many things had changed since 1976, the most significant of these being much lower realizations for molybdenum. In 1976 the high demand for molybdenum and uncertainty of caving characteristics, formed the basis for a very conservative cave initiation sequence with miles of boundary weakening and inspection drifting. In 1991 the highly competitive molybdenum market in conjunction with 15 years of caving experience made for a very different mining climate.

Jan 1, 1994

By Arthur W. Ruff

Estimated reserves of high-grade iron ore at Serra dos Carajás total 16 billion metric tons and have an average grade of 66.7 percent iron, 2.2 percent combined silica and alumina, and 0.05 percent phosphorous on a dry basis. Hematite is predominant and no significant sulfur or other deleterious elements are present. Figure 1 illustrates the comparative magnitude of the Carajás reserves. Serra dos Carajás is located in northern Brazil, about 550 kilometers southwest of Belém, Pará. It is six degrees south of the equator between the Xingu and Tocantins Rivers. Both rivers flow northward toward the Amazon River. The greater part of the area is covered by thick jungle, and the most practical means of access is by air. Figures 2 and 3 show the location of Serra dos Carajás. Figure 4 shows the distribution of the major iron-ore deposits.

Jan 1, 1973

By Carla L. Zenti

In recent years, considerable advances have taken place worldwide in the design and construction of first tunnel linings. With these advances, there is a tendency to move away from traditional support that includes heavy open profiles of rolled steel arches, to a lighter solution with the use of an optimized tubular steel cross section rib, and shotcrete reinforced with steel mesh and/or steel fibers, providing a continuous support (Lunardi, 1982). The development of tubular ribs has provided greater design options, increasing flexibility to engineers and contractors while providing a efficient and cost effective construction method. In this article, the authors describe numerical and experimental investigation on this problem, suggesting as a new first lining steel arch design approach by using tubular ribs cross section as new technical solution for first lining underground support.

Jan 1, 2012

By Haydn H. Murray

Since the advent of machine coated paper in the mid 1930's, the kaolin industry has had a remarkable growth, In 1935 the domestic production of kaolin was 500, 000 tons and in 1970 the estimated production was in excess of 3. 5 million tons. The process industries which use kaolin most extensively are paper, rubber, paint, ceramics, plastics, catalyst manufacturers, ink, and pharmaceutical. The paper industry is by far the largest consumer of kaolin using approximately 70 per cent of the total tonnage mined and beneficiated. Up until 1970 the major kaolin producers were able to expand rapidly enough to supply the demand but for the first time in thirty years the demand is expected to be in excess of mining and beneficiation capacity through at least 1975. The major reason for this is the expansion of coated paper production in Europe and Japan. Two areas supply the lion's share of kaolin for the world markets. These are the Cornwall area in extreme southwestern England and a limited area of Georgia and South Carolina in the southeastern U. S. The English kaolins are primary - (found in decomposed granite) whereas the Georgia-South Carolina kaolins are secondary - (found in lenticular, continuous beds in the Tuscaloosa formation of Cretaceous age. ) The English kaolins are mined by hydraulic methods whereas the Georgia-South Carolina kaolins are mined by dragline or shovel and benefidated by using a wet process for the majority of the production and/or a dry

Jan 1, 1971