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By Yufeng Guo

Mineralogy and physico-chemical characteristics of a nickel hydrometallurgical residue and recovery of iron-bearing minerals by flocculation-magnetic separation were studied. The results show that the nickel residue is super-fine and fraction less than 0.045mm reaches 85.4%. Ferrous minerals are chiefly magnetite and ferruginous glass. Magnetite accounts for 31.7% and exists as free magnetite. Ferruginous glass is of multicomponent amorphous substances with low-iron grade but strong magnetism, and accounts for 39.9% of total iron minerals. Addition of flocculants increases granularity and magnetic force of fine iron-bearing particles and improves iron grade and recovery. The tests with flocculation separation show that a concentrate assaying 56.68% Fe with 81.72% recovery was obtained in a magnetic tube. A concentrate with 56.92% iron grade and 67.96% recovery was obtained by flocculation-magnetic separation with a magnetic cylinder.

Jan 1, 2006

By Harry C. Verakis

A conveyor belt fire presents a serious safety hazard in an underground coal mine. A review of underground coal mine fires involving conveyor belts which occurred within the past two decades was made by the Mine Safety and Health Administration (MSHA). Belt fires that occurred during this period of time have burned as much as 610 m of belting before the fire was extinguished. In an effort to improve safety, MSHA has undertaken a program to study the flammability of conveyor belts in large and small-scale tests. Large-scale tests were conducted on various types of mine conveyor belts using a range of airflows from 0 to 6.1 m/s. Data were obtained to evaluate the effect of airflow on flame spread and other combustion properties of the conveyor belts. The results from the large-scale tests were utilized to develop a new MSHA laboratory-scale test for evaluating the flame resistance of conveyor belts used in underground coal mines. Agreement of results based on a pass/fail criterion was obtained between the large-scale test and new laboratory-scale test. A summary of test results from the new test is shown for different conveyor belt formulations. MSHA also performed a series of fire tests with wood samples using the new laboratory-scale tunnel apparatus. These tests were conducted at airflows from 0.5 to 5.1 m/s to determine the effect on flame spread and burn damage. The data were also analyzed to determine if wood could be used as a calibration standard. The results indicate the flame spread behavior of the wood follows trends similar to results obtained with conveyor belts. The data did not show the precision needed to use wood as a calibration standard. MSHA intends through rulemaking procedures to replace the "20g" conveyor belt acceptance test with the new laboratory-scale test. MSHA also plans to implement a voluntary acceptance program. Under this program, a. conveyor belt manufacturer could obtain an MSHA acceptance for belts meeting the new test criterion. A belt accepted under the voluntary program could then be used underground. Use of conveyor belts meeting the new test would limit the propagation of fire and reduce the probability of igniting other combustibles in the belt entry.

Jan 1, 1991

By Paul Worsey, Seokbin Lim

There are two major types of shaped charges, conical and linear (Ref 1, 2). Conical shaped charges are used to perforate targets and are mainly used by the military as anti armor weapons and by the oil industry for oil well perforation. In contrast, linear shaped charges are primarily used to cut metal in the demolition industry with other uses including separating devices in the space industry. There is a large amount of material published on conical shaped charges because of the high level of defense industry research and funding, however in stark contrast there is very little published on linear shaped charges.

Jan 1, 2003

By Ronald Molnar

"High demand for metals is driving the exploitation of lower grade and more complex orebodies. These projects are often the initiatives of junior mining companies with limited financial resources. In addition, existing operations seek to enhance revenue from their existing metal recovery operations, through the production of value-added by-product metals and chemicals. Typically, hydrometallurgical circuits, often with novel chemistry, are required to exploit these new ores, to produce the multiplicity of products that will make a marginal project economical, or to increase the product range of an existing operation. Often, the mineral processing engineer is given the task of coordinating the development of a back-end hydrometallurgical flowsheet for their mineral processing project. This paper discusses the objectives that companies have when they commission the operation of a hydrometallurgical pilot plant. The paper goes on to enumerate some of the principal differences between mineral processing and hydrometallurgical pilot plants and the effect these have on the design, operability and potential pilot plant outcomes. Important factors include working with chemically reactive solutions and pulps, elevated temperatures operation, changing rheological properties of slurries, the complexity of integrated circuit flowsheets with long hold-up times and multiple recycle streams, and the need in some cases for extreme attention to purity and cleanliness. Examples will be drawn from the extensive experience base of SGS Minerals Services at the Lakefield site, in piloting both mineral processing and hydrometallurgical process flowsheets.INTRODUCTIONWe are currently experiencing a period of strong growth in the demand for metals. This in turn is turning the spotlight on a great many smaller mining companies and mining promotion ventures trying to tap into the rising metal demand. Some of these companies want to develop their properties and recover metals while others want to develop to the point that a major company will take an interest, or in some cases buy them out completely.With the heightened interest in metals, many orebodies that have been known about for years are being reconsidered for exploitation. Often, the reason they have not been developed to date is because of difficult metallurgy and marginal grades leading to marginal economic viability. In both cases the key that unlocks the resources is often the application of a novel metallurgical flowsheet, often a hydrometallurgical flowsheet."

Jan 1, 2006

By G R. Howard, G Back

Management of information systems for data collection is essential to maintain data integrity and continuity, and manage loss control on a large world-class mine such as Telfer Gold Mine. This paper aims to describe the individual systems and protocols of geological data capture at Telfer, then focus on Quality Assurance Quality Control data as an example of loss control in practice. Loss control systems are required to provide capacity, flexibility, structure and management tools to enhance data interrogation. The data that have been collected can then provide geological, financial, environmental, and contractual information to optimise management of business best practice. Telfer Gold Mine is a wholly owned and operated subsidiary of Newcrest Mining Limited. The mine is located in a remote area of NW Western Australia, and has been operating for 20 years. Geological data have been collected at Telfer since 1973. The data include drilling, assay, geological, survey, structural and geophysical data. Data management has evolved through many systems with data stored on many different hardware and software platforms. Commencing in 1995, collation, standardisation and validation of the historic data was completed. This has resulted in the first Access based drill hole database incorporating all available drilling data. This drill hole database, now hosted in SQL Server, is the hub for all geology related data management systems. The Telfer Gold Mine Geology Department has developed a series of inter-related database systems in order to manage the core geology business issues. Databases relating to drill hole planning, drill contract management, geological logging, accounting (standard costing, forecasting, invoice reconciliation), quality control (QAQC), and environment rehabilitation have all been developed to manage loss control. Management effort to provide adequate data systems and protocols has driven the system from concept to utilisation. The improved productivity, data integrity and data analysis capabilities provided by the new database systems at Telfer have allowed for greater confidence in decision making. Systems such as the drill hole and QAQC databases, when utilised in the proper manner provide up-to-date data analysis for resource audits and contract negotiations. The loss control systems are essential to maintain confidence in data integrity and hence directly effect the future of mining at Telfer.

Jan 1, 2000

A Simulation Study on Two-Stage Grinding with High-Pressure Roller Mills By the application of high-pressure roller mill (HPRM) in the field of mineral processing, computer simulation can be used to predict overall performance of a grinding circuit based on data obtained from HPRM comminution test in pilot scale or industrial scale. Using the model developed by Klymowsky and Liu for HPRM comminution and an extended Plitt's model for classification, steady-state of a closed circuit grinding can be calculated by means of a virtual locked-cycle-test conducted on computer. This paper presents the result of a simulation study on two-stage grinding with HPRM as the comminution device. The emphasis is put on the influences of circuit-configuration and way of recirculating classifier's coarse-product on the overall circuit performance. The results show that two-stage grinding with HPRM has its merit and flexibility in meeting demands of various grinding tasks in mineral processing.

Sep 13, 2010

By M. C. Ruiz, M. E. Godoy, J. B. Rivarola, M. W. Ojeda

The amount of Pd recovered from an exhausted olefin hydrogenation catalyst was found to depend on mixing technique, particle size, carbon percentage, chlorine flow, reaction time and temperature. Pd extraction was total when a sample in the 125-175 micrometre particle size range was chlorinated for 60 min at 723 K with 20 cm3 Cl2/min, for 60 min at 748 K with 30 cm3 Cl2/min and for 30 min at 773 K with 30 cm3 Cl2/min. No C addition was needed; the initial C content of the catalyst was sufficient for total recovery. Pd extraction was also affected by heat treatment in different atmospheres before chlorination. Treatment with O2, N2 and N2 with traces of O2 led to different degrees of oxidation of C and permitted the formation of oxidised Pd species. Thermal pretreatment in N2 with traces of O2 was most conducive to Pd extraction

Jun 21, 1905

By M. Yavuz

Underground mining method selection (UMMS) is one of the most important issues in mining engineering. Underground mining method should be primarily selected to make use of underground resources optimally. It is nearly impossible to change the mining method once selected by the reasons of rising costs and mining losses. Because of these reasons, UMMS process is extremely important in mine designs and economics. The strategy of underground mining method selection has been studied by different researchers in the literature. Boshkov and Wright (1973) proposed a classification system; Morrison (1976) suggested a selection chart; Laubscher (1981) proposed a selection methodology; Nicholas (1981) presented a classification system; Hartman (1987) developed a selection chart and Miller-Tait et al. (1995) modified the Nicholas? system and developed the UBC mining method selection process. In reality, UMMS is one of the important Multiple Attribute Decision Making (MADM) problems and mining engineers have always some difficulties in making the right decision in the multiple criteria environment. To make a right decision on UMMS, all known criteria related to the mining method selection should be analyzed and the problem solved according to suitable decision making techniques. A review of the literature reveals that decision making techniques have been used for UMMS applications. Kesimal and Bascetin (2002), Bitarafan and Ataei (2004), Bascetin et al. (2006), Alpay and Yavuz (2007), Karadogan et al. (2008) and Samimi Namin et al. (2008) used decision making techniques in UMMS applications. In this paper, two different MADM methods: Analytic Hierarchy Process (AHP) and Fuzzy Multiple Attribute Decision Making (FMADM) are applied to select the optimal underground mining method for a chromite mine and final solutions are then compared. THE AHP METHODOLOGY The AHP method developed by Saaty gives an opportunity to represent the interaction of multiple factors in complex unstructured situations (Triantaphyllou, 2000). The method is based on the pair-wise comparison of components with respect to attributes and alternatives. A pair-wise comparison matrix n×n is constructed, where n is the number of elements to be compared. The method is applied for the hierarchy problem structuring. The problem is divided in to three levels: problem statement, object identification to solve the problem and selection of evaluation criteria for each object. After the hierarchy structuring, the pair-wise comparison matrix is constructed for each level where a nominal discrete scale from 1 to 9 is used for the evaluation as shown in Table 1 (Saaty, 1980; Saaty, 2000). The next step is to find the relative priorities of criteria or alternatives implied by this comparison. The relative priorities are worked out using the theory of eigenvector. For example, if the pair comparison matrix is A, then, [Amax=××- [1] ] To calculate the eigenvalue ??max? and eigenvector w=(w1, w2,..., wn), weights can be estimated as relative priorities of criteria or alternatives. [ ] Since the comparison is based on the subjective evaluation, a consistency ratio is required to ensure the selection accuracy. The Consistency Index (CI) of the comparison matrix is computed as follows: [CImax--= [2] ] where ?max is maximal or principal eigenvalue, and n is the matrix size. The consistency Ratio (CR) is calculated as: [CR= [3 ] where ?RI? Random Consistency Index. Random consistency indices are given in Table 2. [ ] Table 2. The consistency indices of randomly generated reciprocal matrices As a general rule, a consistency ratio of ?0.10? or less is considered acceptable. In practice, however, consistency ratios exceeding ?0.10? occur frequently. THE FMADM METHODOLOGY The FMADM methods have been developed due to the lack of precision in assessing the relative importance of attributes and the

Jan 1, 2009

By R. L. Marek

The number of persons fatally injured in the California petroleum industry in 1931 was 30, a decrease of 20 fatalities or 40 per cent from the number killed in 1930. As a result of the decrease in the number of fatalities for 1931, the fatality curve of tie California petroleum industry reached its lowest point in nine years. Although reductions in personnel--which permitted the retention of a select and experienced class of workmen, decreased active field-development work, and curtailed production--undoubtedly have had a marked effect on reducing the number of fatalities in 1931, the decrease also has resulted from continued accident-prevention efforts. Statistics show that a direct relationship exists between development activity and the number of men accidentally killed in the drilling and producing division of the California petroleum industry. For example, when the average number of drilling wells in 1930 was 29 per cent less than in 1929, the number of men accidentally killed at drilling wells dropped 48 per cent; and when the average number of drilling wells in 1931 decreased 52 per cent from 1930, the number of fatalities at drilling wells decreased 58 per cent. The relationship between field-development work and fatality frequency is significant because each year at least 50 per cent of all the fatalities in the California petroleum industry occur in the drilling and producing division. This relationship should serve to guide the accident-prevention efforts of the industry, especially in the drilling and producing division, toward checking an increase in fatal accidents when development activity again takes an upward trend.

Jan 1, 1932

By Murray Jacobson

A method for determining airborne trona dust concentrations using a midget impinger was developed. During sampling, the trona dust, composed of sodium carbonate and bicarbonate, dissolves in the collecting medium (water). Resulting solutions are then titrated using 0.1 [N] hydrochloric acid solution. The mass concentration of the trona sample is determined from a calibration curve relating the volume of acid required for neutralizing a collected sample to the mass of the dust. Test results obtained using this method are equivalent to those obtained using a gravimetric sampling method.

Jan 1, 1971

By Daniel G. Di Canio

Reference information and user instructions for Version 3.0 of the Accident Cost Indicator Model (ACIM) software package are presented. ACIM estimates the tangible costs of occupational injuries, illnesses, and fatalities in the United States mining industry.

Jan 1, 1983

By Aleksandar D. Bugarski, Robert J. Timko

Despite extensive research efforts conducted in the past decades, occupational health risks associated with exposure to nano and ultrafine aerosols emitted by diesel power equipment are still not completely understood. The complexity of physical and chemical properties of diesel aerosols, constantly changing with the implementation of advanced diesel emissions control technologies, make this task rather challenging. The objective of this paper is to identify and characterize nanometer and ultrafine aerosols emitted by diesel engines in the underground environment and evaluate the effects of selected contemporary control technologies on physical properties, chemical composition, and in-vitro toxicology of diesel aerosols. The physical and chemical properties of the nanometer and ultrafine diesel aerosols are to be characterized through a test series in the NIOSH Lake Lynn Laboratory experimental mine. The crucial part of the study has been development of a facility that allows researchers to generate field results with precision and accuracy characteristics of a laboratory environment. The knowledge obtained from this study should strengthen our understanding of the health implications related to exposure to diesel particulate matter and aid in assessing the potential of various control technologies for reducing this exposure.

By Gregg A. Scott, Gordon F. Revey

"The Folsom Dam is a 340-foot-high concrete gravity dam with embankment wing dams located on the American River about 20 miles northeast of Sacramento, California. Folsom Dam is operated andmaintained by the U. S. Bureau of Reclamation (Reclamation). As part of the Central Valley Project,Folsom Dam is a multipurpose facility providing water supply storage, flood control, power generation, and recreational opportunities."

Jan 1, 1999

By G. T. Hong

A numerical model for use in design is developed to predict the stresses and axial and bending displacements in a drilled pier in expansive soils. The prediction is based on the horizontal swelling pressures and uplift forces which act on the side of the drilled pier. The exponential suction envelope with the depth within the moisture active zone is estimated based upon the equilibrium suction, moisture diffusion coefficients obtained from laboratory tests, and minimum suction at the ground surface of the site based on field conditions. The volume change of soil is based on suction variations, soil properties, overburden pressures, crack influences, and the relationship between moisture contents and suctions. Considering the movement active and anchor zones on a soil-pile system in expansive soils, horizontal swelling pressures are formulated using the shear strength of an unsaturated soil and the Mohr?s circle and failure envelope. The movement active zone has two sub-zones in which horizontal swelling pressures are attributed to passive earth pressure failure and suction change in the upper and lower sub-zones, respectively. Horizontal swelling pressures which occur in the anchor zone are assumed to be in the at rest condition. The shear stress generated on the vertical surface of a drilled pier is supported by the nonlinear curves of load transfer versus relative displacement. The axial behavior and lateral bending of the pier in expansive soils are simulated using a beam column approach. The computed axial and bending displacements and stresses are used to provide structural design of the pier. Figures of computed results for typical cases are presented.

Jan 1, 2007

By D. E. Wolfson

As a part of its overall program of coal carbonization, the Bureau of Mines is studying the coking properties of coals that may be used for metallurgical purposes. The objectives of this study were given in detail in a previous report.2/ The inherent suitability of coal for metallurgical use depends primarily on (1) chemical composition, (2) preparation characteristics, and (3) carbonization behavior. The first two factors, as well as the available reserves, are considered in selecting coals for carbonization tests. According to the estimate of reserves by Dowd,3/ the recoverable coal in Floyd County in beds 28 inches or more thick, in thousand tons, is as follows: [ ]

Jan 1, 1958

By L. Lehasa

The purpose of the project was to investigate the challenges faced by Khutala Colliery pertaining to underground road construction and maintenance. Furthermore the influence of these challenges on productivity and safety requirements were taken into consideration. The operating standards required for the construction and maintenance of the 2 seam road transport infrastructure was investigated, together with reasons why the standards of operating procedure are not met. The Code of Practice put in place by Khutala Colliery was used to view the standard operating procedures. Leading practices on underground road construction were researched. The project aims to discover the gaps that Khutala Colliery must bridge to implement enhanced practices with regards to underground road construction. During the period of study, observations were carried out to determine whether the road construction standards of operating procedure were being adhered to at all times for both road construction and road maintenance. Khutala Colliery has put in place a traffic management plan, which includes safety practices and work policies that must be adhered to while travelling on underground transport roads.

Jan 1, 2012

By R. G. Gürtunca

Over the past century coal miner safety and health has seen tremendous improvements, the fatality and injury rates continue to decrease while productivity continues to increase. Many of the hazards that plagued miners in the past, such as coal bumps, methane and coal dust explosions, ground fall accidents and health issues have been significantly reduced. The contribution of NIOSH research includes products for prevention and survival of mine fires, methane control measures, design procedure for underground coal mines, methods for excavation surface controls, methods and procedures for blasting, laser usage in underground mines and prevention of electrocution from overhead power lines that have reduced accidents and injuries in underground coal mines. Health research has produced products such as the personal dust monitor, noise abating technologies and ergonomic solutions for equipment operators. Research priorities at NIOSH are set by considering surveillance statistics, stakeholder inputs and loss control principles. Future research in coal mining is directed towards respiratory diseases, noise induced hearing loss, repetitive musculoskeletal injuries, traumatic injuries, falls of ground and mine disasters. The recent spate of accidents in coal mines resulted in the Miner Act of 2006 which includes a specific role for NIOSH in future mine safety research and development. The mine safety achievements in the USA reflect the commitment of industry, labour, government and research organizations to improving the safety of the mine worker.

By P. J. Bartlett

Premier Diamond Mine exploits a kimberlite orebody using cave mining methods. A drilling level is established at the base of a block of ore to effect undercutting that leads to caving of the overlying ore. A second level is developed some 15 metres below the undercutting level to allow extraction of the ore once it has caved. As much as 45 per cent of the rock is removed on the extraction level creating a series of pillars. Undercutting creates abutment stresses, as high as 3 times the virgin stress, which affect the rock mass to a distance of 20 metres from the undercut face on the undercut level and on the extraction level 15 metres below. If the extraction level is completely developed prior to undercutting, where stress levels exceed 20 percent of the rock mass strength, extensive rock mass and support damage occurs as the undercut passes overhead. Rock mass damage takes the form of movement along existing joints and minor shear failure through intact rock. Support damage takes the form of cracking in rigid concrete linings. Where induced stresses exceed 50 per cent of the rock mass strength it is often impractical to keep excavations on the extraction level open. Rock mass damage takes the form of extensive failure of the rock in shear which evidences itself as propagation of the fracture zone around tunnels and footwall heave. Support damage results in destruction of shotcrete linings and concrete footwalls. As the interbolt support fails, badly fractured rock ravels around the steel tendons. Observation and monitoring at Premier Mine and on other cave mines has shown that induced stress levels and consequent damage are a function of :?the extraction ratio on the undercut and extraction level prior to undercutting ?the shape of the undercut face ?the rate of undercut advance ?the distance of leads and lags between adjacent tunnels on the undercut level. To ensure the stability of excavations, all of the above parameters must be carefully planned and the planned mining sequence rigidly enforced. The minimum of development is completed on the extraction level prior to the undercut passing overhead. Required development is then rapidly completed once the area has been de-stressed. Support is installed in three phases: ?Rockbolts are installed as soon as excavations are developed ?Wire mesh, steel tendon straps and a layer of shotcrete sufficient to protect the mesh and straps from damage by blasting and LHD loading is installed as soon as practical thereafter. Inevitably the shotcrete lining has to be replaced once the undercut has passed overhead.. ?Rigid shotcrete linings and concreted footwalls are completed only after the undercut has passed overhead and the area has been de-stressed.

Jan 1, 2000

By John C. Machisak

The National Safety Competition is sponsored and conducted annually by the Bureau of Mines, U.S. Department of the Interior, to give greater impetus to the building of programs safeguarding the employees of the mineral industries from disabling work injuries. The results of the 1960 National Safety Competition are presented in this publication. Mines and quarries that were awarded the Sentinels of Safety trophy for the best safety record in their competitive group and those mineral operations that ranked second, third, fourth, and fifth in the competition are listed with a summary of their achievements in preventing disabling work injuries. In addition, this publication presents statistical data on disabling work-injury experience in all other mines and quarries participating in the annual competitions.

Jan 1, 1962

By H Peiming, W Sakurai, Y Matsuhisa, H Shimazaki, Y Fukahori

Oxygen and carbon isotope mapping of hydrothermally altered wall rocks was applied to the blind ore prospecting of skarn Pb-Zn deposits in the Kamioka mining district, centralJapan, where the wall rocks consist of heterogeneous rock units. The results (d18OSMOW of -1.1 to +17.3ë and d13CPDB of -5.0 to +4.8ë for limestones, and d18OSMOW of -0.8 to +12.5ë for silicate rocks) show isotope zonations of the wall rocks with depletions in heavy isotopes (18O and 13C) toward the centre of mineralization. The isotope zonations likely formed by interaction of migrating thermal waters with the wall rocks during the mineralisation. The heavy-isotope depleted zone, which indicates higher temperature or higher water-to-rock ratio of the system, occurs in the footwall of a fault, indicating that the fault played the role of main conduit of the ore-forming fluids. A heavy-isotope depleted zone was also found in an area, where significant mineralisation had yet to be identified. Recent drilling in this area has intercepted a zone with a grade of 16.0% Zn, 0.8% Pb, and 35g Ag per metric tonne at a depth of about 360 m.

Jan 1, 1995