Search Documents

By Yunsheng Yao, P. Golledge, A. D. S. Gillies

In order to investigate the explosibility of sulphide mineral dusts, sulphide ore samples were collected from five underground metalliferous mines in Australia. The mineralogical and chemical composition of the dust samples was analysed by X-Ray Powder Diffraction and Atomic Absorption techniques. Simulated post detonation fumes were produced and used in dust explosibility tests to examine the influence of the fumes on sulphide dust ex- plosions. These tests were conducted in a 20 Litre Siwek Explosion Chamber with measurement and control system that is regarded as a standard testing system worldwide for dust explosion studies. The dust mineralogical composition and dust explosibility tests indicated that the content of sulphur can not accurately predict the explosibity of the sulphide dust. The percentage content of pyrite in the sulphide dust can be a relatively reliable diagnostic criterion in evaluating the risk of sulphide dust explosions in the mining of a massive sulphide orebody. The hybrid explosion tests demonstrated that the post detonation fumes from ANFO not only decrease the lower explosion limit of the sulphide dusts, but also increase the severity of the dust explosions. The explosion pressure reaches its peak value when the fumes content in the explosion chamber is about 20 per cent by volume

Jan 1, 1997

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 M. A. Rodrigues da Silva Enríquez

One of the rare consensual points among different resource-based economic analytical approaches refers to the strategic role of rent from mineral extraction, as a decisive tool to ensure that the temporary wealth generated in the present can turn into permanent income in the future. For this reason, evaluation, distribution and use of mining rent plays a central role in the sustainable development of mining cities. Brazilian legislation provides for this at the municipal level by means of participation in the financial results of mineral extraction accomplished in these municipalities, with the Financial Compensation for Mineral Exploration (CFEM). CFEM is a type of ad valorem royalty, which charges taxes of up to 3% of the net revenue of mineral production. However, legislation does not establish how these resources should be used. Therefore, there is wide variation in the use of CFEM income among Brazilian mining cities. A study from a sample of the 15 largest mining cities in eight Brazilian states made possible identification of two main patterns with regards to the use of CFEM which were labeled "sustained use" and " the pitfall of the single treasury." In that regard, this article discusses the pressuring factors that contribute to these patterns, as well as the institutional arrangements which may be more favorable to inducing more sustained use of CFEM.

Jan 1, 2011

By W. L. Freyberger

In many papers concerned with fundamentals of the froth flotation process, authors have considered the contents of a flotation cell to be comprised of two immiscible phases, the froth and the pulp. I (Of course, each of these phases is in turn made up of several solid phases plus air and water.) This generalized concept of the flotation system can be extended by considering the cell contents to include two phases: an extracting phase, the air bubbles plus the collector, which removes a selected mineral component from the second phase, the ore pulp. Thus, there is an analogy between a flotation system on the one hand, and chemical extracting systems, such a solvent extraction system or a leaching system, on the other hand. Such extracting systems may be operated in cocurrent or countercurrent fashion. This paper includes first a brief discussion on the general nature of cocurrent and countercurrent operation as applied to froth flotation, and then presents the experimental results of flotation of a specular hematite ore by each method, using a tall oil fatty acid as collector. Cocurrent Flotation A conventional flotation circuit involving roughing, scavenging, and cleaning flotation is illustrated schematically in Figure 1. In such a circuit the col¬lector, or extractant, and new feed ore enter together at the head of the rougher circuit, and flow cocurrently to the scavenger circuit where more collector is added. According to this practice, sufficient collector is added to the head of the rougher (and scavenger) so that the final tailings are of low enough grade to be discarded. Since the flow of collector and ore is cocurrent, the process consists of single stage contact between the extracting phase and the ore pulp. If the scavenger concentrate is recycled to the head of rougher, the overall circuit has some of the characteristics of countercurrent flow. In such a case part of the extractant (collector) is added at the discharge end of the circuit, and may

Jan 1, 1971

By R. K. Mehta

Stirred ball mill feed used for ultra-fine grinding application requires fine size separation step in order to avoid over-grinding. This paper presents the selectivity curves obtained for oil shale and complex sulfide are using 460 mesh (30 micron) Derrick vibrating screen. Interestingly, the selectivity curves generated from the experimental data were monotonic increasing selectivity for oil shale but not monotonic increasing for sulfide ore. These non-monotonic increasing selectivity curves were similar to the mechanical air separator fishhook selectivity curves described by Luckie and Austin. A 2 stage classification in series model describing the fishhook selectivity curve has been used in proposing the classification mechanism for fine vibrating screens when heterogeneous multicomponent sulfide are undergoes size separation.

Jan 1, 1992

By Erik Marsh, Frederick C. Harris Jr., Javad Sattarvand, Joshua Dahl, Alireza Kamran Pishhesari

Based on the mine safety and health administration (MSHA)reports, mining truck accidents are among the significant causes of fatalities in the mining industry. The major causes of haulage accidents can be divided into non-driving and driving factors, such as truck-related sudden failures and operator performance. Numerous parameters affect trucks' safe operation, but situational awareness plays a significant role. Due to the distinct structure of mining trucks, making them efficient for mining purposes, the operator has a very limited field of view (FOV), making them prone to accidents resulting in losing lives. The cabin's position blocks the truck's right and rear sides, creating several blind points around it. Aiming to test/train the operator's awareness of the surrounding, a proximity detection system is developed through a multiplayer virtual reality (VR) application to investigate the human factor in equipment collisions. The operators were examined and monitored when asked to conduct what exactly happened in the Marigold mine truck accident without being aware of the scenario. After receiving sound, vibration, and visual alarm warnings, their reaction and performance were analyzed. The platform is developed using the Unity game engine for HTC VIVE virtual reality goggles. An Omni-direction treadmill and a motion simulator platform are utilized for the player and dump truck operators. Fifteen students were monitored when driving the dump truck receiving/not receiving proximity detection alarms. None of them repeated the accident when receiving proximity alarms. Also, they found the visual alarm the most comfortable while driving the truck.

Jun 25, 2023

By Kenneth P. Neumann

The development of the Cyprus Thompson Creek Molybdenum Deposit near Challis, Idaho, began in 1967 when the first mining claims were staked on the intrusive rock outcrop. Exploration drilling continued for the next 14 years. During 1978, a decision was made to develop the deposit. In December, 1980, approval of the Environmental Impact Statement was received and construction of facilities and waste rock removal began. By the middle of 1983, 126 M metric tons of rock had been removed and all facilities were completed. The high work ethic of Cyprus Thompson Creek employees combined with innovation has made the mine one of the most efficient in the United States today.

Jan 1, 1983

By O. Tranbarger

In aging tunnels, wall and roof deterioration can eventually result in defects that must be detected and repaired to maintain safe structural conditions. In investigating tunnel defect conditions, a specialized FM radar system was developed with a programmable VHF and UHF operating sweep range for optimizing the penetration and measurement capabilities. The new FM radar technology was tested in two aging brick-lined tunnels in New York City. Test results showed that FM radar signals could penetrate eight courses of water-saturated brick and that the original steel liner outside the tunnel walls was intact.

Jan 1, 1985

By E. Stolarski

The circulating fluid bed (CFB) technology can proudly point to its history of more than a quarter of a century of commercial operations. Over 80 CFB units operate in aluminum calcining, coal combustion and gold roasting. This paper describes the invention of the circulating fluid bed and chronicles its development and evolution from calcining through coal combustion to gold roasting. It presents performance data of Lurgi's CFB units in operation and highlights the six gold roasting plants currently operating throughout the world.

Jan 1, 1998

By John E. Roberts

People are not a novelty. But the phenomenal numbers thereof, who have approached, settled, and been born in California in the past twenty-five years, are such a problem as to be a novelty in the broadest sense of the word. California, with less than 7,000,000 people in 1940, and over 19,000,000 in 1966. In 5 1/2 years, (1960-65) the southerly 14 counties of California, which together comprise one-half the land area of our state, had an increase in population greater than Colorado, or Arkansas, or Oregon, or any one of 19 other states.

Jan 1, 1967

By P. R. Hervey, J. W. Foise

Quartz is the second most widely used electronic material, with approximately 3,000 t (3,300 st) of single crystals used each year. Most of the quartz used in electronics is synthetic and is manufactured using a technique called hydrothermal growth. This paper reviews the basics of hydrothermal growth, the feedstocks used for these crystals and the challenges to improving the growth process. This paper also reviews the processing of these crystals, the markets and applications where they are used, and the global outlook for these markets.

Jan 1, 2002

By Jacques B. Wertz

It is well known that the major fractures and lineaments presently recorded in Western North America are preferentially oriented along a general northwest direction (Figure 1). There are other features, however, more subtle, more elusive as a rule and which can only be inferred, occurring at right angle to this broad NW direction. It is intended a) to examine some of these NE or transverse trends, b) to compare these regional NE breaks to similar ones that transversally cut through the eastern part of the European Tethys, more specifically in Iran and Turkey, and c) to study their potential relationship to mineralization in both areas.

Jan 1, 1973

Underground instrumentation and observations at longwall panels have demonstrated that the growth of main roof causes an extremely high roof weighting on the shields. It can sometimes result in catastrophic effects on the support when the roof weighting intensity far exceeds the support capacity. In this paper, a comprehensive study was conducted on characteristics of main roof breakage and its effects on shields at different locations, based on the monitored shield data, theoretical analysis, and finite element analysis. With the help of theoretical analysis and numerical modeling, stress distribution and redistribution in the main roof were analyzed in detail to define main roof failure modes and understand the maximum roof weighting intensity imposed on the shields. From this study, it was found that the effects of main roof breakage on shields are chiefly related to the shield initial setting condition and the final failure mode of the main roof.

Jan 1, 1994

By K. N. Han, M. C. Fuerstenau, T. B. Onlin

A mathematical model describing the concentration profile of fine particles in the axial direction in liquid fluidized beds has been developed for the removal of fine particles. A forward finite differentiation technique has been used to solve a continuity equation with a source term to predict the concentration profile and, hence the recovery as a function of time. With the aid of experimental results obtained using a fluidized bed of 3-cm diam, dimensionless parameters were identified. These parameters were used to predict the concentration profile of fine particles in fluidized beds of larger sizes. Four different sizes of fluidized beds, namely, 1.3, 3.0, 4.0, and 7.5 cm in diam, were used in this investigation. The amounts of bed particles used included 4, 8, 16, 24, 59, and 120 g, and the size of bed particles were 48x100, 100x150 and 150x200 mesh.

Jan 1, 1987

By James Lett

The role of pre-conditioning in a caving operation has multiple benefits, ranging from assisting with improved caveability, normalising fragmentation and improving draw point hang-up frequency. At Newcrest Mining’s Cadia Operations, both the Ridgeway Deeps block cave the Cadia East Panel Cave have utilised pre-conditioning using hydraulic fracturing. Seismic response data inside and outside the pre-conditioned volume show the benefit of treating the full caving block. Cadia East has further developed pre-conditioning to mitigate developing seismic hazards associated with major structures (fault-slip events) and managing mine-wide seismic hazards in new caving operations where the potential for large damaging seismic events exists due to high stresses and hard competent rockmasses. A case study reviewing the impact of pre-conditioning to mitigate seismic hazard associated with fault slip is presented. Cadia East operation undertook a targeted hydraulic fracturing program and reduced the overall number of large events as an example of the benefits of pre-conditioning. This paper will review the application of Hydraulic Fracturing at Cadia and discuss the geotechnical and seismological parameters of seismic events that occur within and outside of pre-conditioned rockmass volumes to demonstrate the benefits that Hydraulic Fracturing bring to future caving operations.

Apr 26, 2022

By James A. Finch, Xiang Zhou, Yue Hua Tan

Widely used as collectors for nonsulfides, amines also show some frothing properties. Evaluating frother functions of amines and their combination with conventional frothers addresses whether one reagent delivering both collector and frother functions compromises the efficacy of either. From the findings, whether blending with frother confers any benefit requires knowledge of the residual amine concentration. If it is below about 10 ppm, blending eliminated coalescence, but there appears to be no benefit if the concentration is above 15 ppm.

By William J. Maloney

Blind drilled shafts are becoming increasingly popular as a secondary and sometimes primary means of ventilation. This is particularly true in the Appalachian coalfields. Some reasons for the rebirth of blind shafts are economics, timeliness, safety characteristics and their inherent independence from underground operations. Blind drilling has had limited use in hard rock and tunneling ventilation. Advances in cutters, bit design, equipment and lining systems have made blind drilled shafts the shaft construction technique of choice for ventilation specialists. History of blind drilling Blind drilling's roots include the Nevada test site, the coalfields of Appalachia and Germany, and the uranium mines of Arizona. Early technology was developed using a variety of equipment mainly of oilfield origin. Shafts completed by oilfield equipment ranged from the shallow 1.5 and 1.8 m (5 and 6 ft) lined shafts on the Nevada test site to two 3 m (10 ft) lined, 222 m (730 ft) deep shafts in Alberta for heavy oil development. Several of these shafts were completed to extraordinary depths. The record, completed in 1969, is a 2.28-m-diam (90-in.-diam), 1875-m (6150-ft) deep shaft, located in the Aleutian Islands of Alaska.

Jan 1, 1993

By K. J. Reid

With the current trends of increasing costs and decreasing head grades the mineral industry is no longer operating in very high profit areas and has been forced to pay greater attention to the application of modern technology. Although here are many technological advances to the credit of the industry in recent years there are still many processes being operated in the traditional manner and still many areas awaiting the application of methods which have been proven in other industries. Compared with the chemical industry the mineral industry is seriously ageing in the general areas of process analysis and process control, more so than can be justified by the complications arising from having to deal with particulate systems with properties far different from ideal, or even non-ideal, liquid systems. One area in which there has been a remarkable lack of application in the Mineral industry is that of analog computation and the authors feel that there is considerable scope for the use of the analog computer in studying mineral industry processes. The paper outlines the basic principles and features of the analog computer and describes its role as a simulation tool in some engineering and mineral processing systems.

Jan 1, 1972

By Qinbo Cao, Qianshan Peng, Heng Zou, Xingcai Yu

Rutile ore is an important resource for the production of titanium products, and flotation is an efficient method to enrich rutile from its deposits. Motivated by strong commercial demand for titanium metal and alloys, substantial efforts have been made to improve the flotation efficiency of rutile. Styryl phosphonic acid (SPA) and salicyl hydroxamic acid (SHA) are commonly used as collectors for rutile flotation, and lead (Pb) ions can be used as activators for rutile flotation with SPA or SHA. Xanthates have a price advantage over SPA and SHA for the flotation of sulfides as SPA and SHA prices are higher than xanthate prices. In this work, we found that when rutile is activated by lead ions, amyl xanthate is an efficient collector for rutile flotation at pH 8. A slightly basic slurry can be readily obtained. Moreover, the price of amyl xanthate is lower than that of SPA or SHA. In this regard, this flotation strategy has the potential to be used in industry. Furthermore, the adsorption features of amyl xanthate on the Pb-activated rutile surface was investigated by experimental methods, which provides insight into the role of lead ions in rutile flotation.

By J. C. Stankus, K. J. Ma, D. Faulkner

To protect mine personnel and moving equipment at underground roof fall areas, mine operators typically install steel sets, which are covered with wooden blocks and backfilled with an expanding-type cement material. In large roof falls, the cost of void backfilling becomes prohibitively high, causing some mines to leave the voids open. However, the durability of wood over time and the capability of the steel set and wood lagging to resist falling rock are unknown. This has caused concern for the U.S. Mine Safety and Health Administration (MSHA) and ground control engineers. During the last few years, Keystone Mining Services, LLC developed various impact-resistant steel set designs that were approved by MSHA and installed in various underground fall rehabilitations. This paper presents an impact-resistant steel set design methodology, including (1) steel set design per AISC national standard, (2) design, development and laboratory testing of a waterproof coated impact-resistant lagging panel and (3) impactresistant steel set design based on the law of conservation of energy. Two underground cases will be included detailing the application of the system.

Jan 1, 2011