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By Stephen C. Tadolini

The International Ground Control Conference in Mining has always provided an open forum for the publication, presentation, discussion, and often heated debate on roof bolting systems mostly with attention to how, when, and why they work. During the last 24 Conferences at least 170 papers have been presented by International Experts on these ?simple? devices that range in length from 30-inches to 20 ft and from 5/8 to 2 inches in diameter. Roof bolts are primarily mechanically anchored, glued, cemented, or driven. Bolts are placed vertically, angled, or tied together with special fixtures (trusses and slings). They have been termed active, passive, stick-slip, and several other descriptive acronyms or mining slang expressions. This retrospective paper will present the changes in bolt types and usage, point out some of the biggest myths and hail the most significant advances (according to the authors? opinions of course).

Jan 1, 2006

The Bureau of Mines conducted large-scale laboratory copper ore leaching tests to enable improving copper recovery from large dump-leaching operations. This was done by comparing leaching progress when copper was recovered from recycled leach liquor either by cementation or by solvent extraction. Copper was leached from 7-ton ore samples at room temperature using pH 2 ferric sulfate solutions. With are samples containing 11 percent minus 0.5-inch fines, no marked advantage in using either of the copper recovery methods was evident after 416 days of leaching. With ore containing 32 percent minus 0.5-inch fines, solvent extraction of copper was advantageous in that 60 percent of the copper was extracted after 568 days, whereas only 48 percent of the copper was extracted when cementation was used. Less acid was consumed during leaching when solvent extraction, rather than cementation, was used for copper recovery. Iron, contributed by cementation with scrap iron, plugged the ore bed containing 32 percent fines.

Jan 1, 1981

By Narendra Gupta, Gaurav Srivastava, Abhinav Sharma

From the days when plain detonators and safety fuse were used for initiation of commercial explosives, the commercial blasting and mining industries have made rapid strides. With the advent of electronic detonators in the late ‘90s, the face of commercial blasting was changed forever. The Mining Industry in India initially took a while to embrace Electronic Blasting Systems (EBS), however, more recently the industry has taken to EBS in a big way.

Jan 1, 2015

By S. Agarwal, S. Frimpong

The creation and maintenance of a healthy working environment in surface mining operations require sustained efforts in pursuing advanced research initiatives toward the development and deployment of powered haulage technologies. This paper contains progress summary on a frontier research in truck dynamic control, vision and collision avoidance. This research is required to provide solutions to challenging problems regarding operator visibility in truck haulage in a surface mining environment. The paper focuses on truck control kinematics and dynamics, truck-haul road interactions, intelligent truck sensing, intelligent truck collision avoidance system, integrated system for situational awareness, augmented visualization and operator interface, and field testing and error variance modeling of developed technologies. A sensor suite of four subsystems, including front-side stereo-camera, front-side Doppler radar, close range sonar proximity sensors, and rear-side camera system have been recommended for developing a 360° truck operator vision to allow safe operations. This research initiative is significant because it will provide a strong basis for developing technologies to improve truck haulage safety in surface mines and construction sites.

Jan 1, 2007

The lignite deposits of the United States represent a huge potential source of fuel for power generation. It has been estimated that lignite constitutes about 24 percent of the remaining National reserves of solid fuel on a tonnage basis and about 15 percent of the reserves on a B.t.u. basis. (See sec. 3, part 1.) The major portion of these reserves is in North Dakota. Lignite has been used locally for domestic heating since the first settlers burned it at forts and fur-trading posts as early as 1855. Some of the first studies of the use of lignite in steam boilers were conducted by the Federal Bureau of Mines from 1910 to 1920 (15, 19) 1/ However, the commercial utilization of lignite as fuel for producing power developed slowly. Not until about 1925 was any really successful lignite industrial fuel-blaming equipment developed. Since then the commercial use of lignite as a fuel for producing power has been increasing steadily.

Jan 1, 1954

By David E. Fogelson

One model each of three different makes of portable displacement seismographs was calibrated on a shaking table capable of 5,000 pounds of force, Calibration tests were conducted in the frequency range of 5 to 200 c.p,s, and in the amplitude range of 0,002 to 0.05 inch peak-to-peak, The seismographs were tested under two mounting conditions: (1) The feet of the instrument were bolted to the shaking table, and (2) the feet were resting on emery cloth affixed to the table, The results of these tests show that, in the frequency range of 5 to 40 c.p,s, and for vibration levels less than 0.2 g, the magnification for all three instruments is constant with input level but varies slightly with frequency. For vibration levels greater than 0.4 g. and for frequencies greater than 40 c.p.s., the magnification of all three instruments shows large variations with frequency and amplitude of table motion.

Jan 1, 1962

By J. A. Kosek

Work has been carried out under Bureau of Mines Contract No. HO395132 to develop and fabricate gas sensors for mining applications. Promising new instruments have been designed, developed, tested and supplied to meet BuMines requirements. These instruments include prototype 1) remote-sensing, diffusion-type CO monitors for mine operation which can be operated in conjunction with a surface computer, 2) control modules for alternate in-mine readout of the remote diffusion type CO monitors, 3) personal CO diffusion-type dosimeters and 4) personal NO diffusion-type dosimeters. In addition, retrofit modifications were made to update and optimize operation of CO and NO2 direct-reading type detectors provided under a previous contract. Studies were conducted to evaluate and demonstrate the availability of stable, portable N02 calibration sources for NO2 instrumentation. The use of selected, commercially available cylinder sources for NO2 instrument calibration were recommended. Additional studies were also conducted to investigate the feasibility of instrumentation for rapidly monitoring CO, NO and NO2 in diesel exhaust.

Jan 1, 1981

By R. Gensemer

A number of state and federal agencies are calling for development of aquatic life criteria for conductivity. These aquatic life criteria or ?benchmarks? are based on observed correlations between conductivity and benthic macroinvertebrate community composition, generally measured by composite metrics or indices. However, development of an aquatic life criterion for a composite variable like conductivity is made difficult by a number of factors. Based on a database from West Virginia, observed patterns of invertebrate community composition versus conductivity may instead be related to a combination of abiotic (e.g., ionic composition, habitat) and biotic (e.g., life history, colonization potential) factors. Many benthic invertebrate taxa also do not respond to increasing conductivity in a consistent relationship. Many states have determined that a composite variable, like conductivity or TDS, is not appropriate for criteria development, as many studies have shown that toxicity varies as a function of ion composition and can be mitigated by elevated hardness. We conclude that the relationships between conductivity and changes in benthic macroinvertebrate community composition are neither strong nor reliable enough to warrant derivation of a criterion based solely on conductivity.

Jan 1, 2011

Study on Iron Ore Sintering with High Proportion of Specularite Concentrates Specularite iron ores have poor hydrophilicity and ballability as well as bad high-temperature reactivity, which restricts the large-scale application in the sinter and pellet production. In order to make the best use of the specularite concentrates, a novel process of Composite Agglomeration Process (CAP) is applied in this research. By the CAP, the percentage of specularite concentrates in the sinter mixture is increased to no less than 40 per cent as well as the coke breeze dosage is reduced by 0.3 per cent~0.6 per cent. Moreover, all the sintering indexes are obviously improved compared with the traditional sintering process. Researches on the metallurgical performances shows the finished composite agglomerates are high-quality burdens for blast furnaces. This investigation can provide an effective route to utilize the inferior specularite concentrates in the sintering.

Sep 13, 2010

By Sidney Katell

This report covers the period January 1964 through December 1964; it is a continuation of the series that began with the publication of Information Circular 7516 in October 1949. Also, it is the sixth in a series of reports prepared under a cooperative agreement between the Bureau of Mines and the American Association of Cost Engineers. The agreement provides for the publication of an annual cost bibliography with the work load involved in the preparation shared equally. The abstracted articles, concerned with all facers of cost engineering in the field of chemical and petroleum. plants and related subjects, are from the following sources:

Jan 1, 1965

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

By T Davids, B J. J Botha

The presence of an extensive soft siltstone layer in the middle of the inter-burden sequence of rocks at Syferfontein Colliery in South Africa prompted tests to determine the effect of different mid-column decks of inert material in the siltstone layer. The objective was to achieve significant cost savings in explosives use whilst not degrading dragline productivity. An important factor that had to be considered was that the initiation systems available in South Africa are not accurate enough to ensure simultaneous initiation of explosives decks in a hole.

Jan 1, 1994

By Brad Bulow

Blasting is an essentially violent process aimed to disrupt and loosen rock for productive excavation. Some dilution of any ore present is the inevitable result. This makes blasting a dirty word to most geologists, particularly in narrow vein gold mines. A 1% increase in gold recovery may be worth $1 M extra revenue to a large mine.

Jan 1, 2000

By A. Fredriksson, R. Christiansson, I. Staub

A theoretical model based on DFN models and 2D DEM numerical modelling has been developed for evaluating the rock mass mechanical properties. The description of the methodology is non-site related and can be applied in any site for this type of characterisation. The methodology was developed in the frame of the Site Investigation programmes for a Deep Repository for spent fuel in Sweden, and validated on sets of data coming from the Äspö Hard Rock Laboratory. Un modèle théorique base sur des modèles probabilistiques de réseaux de fractures et sur un modèle numérique DEM 2D a été développé dans le but de déterminer les propriétés mécaniques de la masse rocheuse. La méthodologie développée peut être appliquée à tout type de site pour ce genre de caractérisation. Le modèle a été élaboré dans le cadre des programmes de recherche d’un site d’enfouissement des déchets nucléaires en Suède, et validé par une application au laboratoire de recherche souterrain à Äspö. Ausgehend von DFN-Modellen und 2D DEM numerischen Modellierungen wurde ein theoretisches Modell für die Auswertung von mechanischen Eigenschaften von Fels entwickelt. Die Methodikbeschreibung ist nicht standortspecifisch sondern kan überall für diesen Typ von Standordkarakteriserung angewendet werden. Die Methodik wurde in Schweden im Rahmen der Standortuntersuchungsprogramme für die Endlagerung von verbrauchten Brennelementen entwickelt und ist mit Hilfe von Daten des Äspö Hard Rock Laboratory validiert worden

Jan 1, 2003

By Valentin Choquenaha Bombilla, Oscar Alvarez Muiloz

"Tintaya’s basic production line is copper concentrate, which has an important gold content. The process used is flotation; the objective of the metallurgical department is to obtain the best results in the copper recovery without neglecting the gold, using very specific reagents. Copper recoveries are considered high, nevertheless every day emphasis is placed upon increasing those recoveries. Regarding gold, optimum recoveries could not be achieved with flotation; and implementation of a gravity circuit was considered.According to microscopy studies, the coarse and very fine grains of gold in native form are lost to tails. The native gold due to its high specific gravity is concentrated at the underflow of the cyclone, remaining in the circulating load of the circuit. It reaches three times the concentration compared to the head grade entering the ball mills. This re-circulation generates very fine and laminated gold particles inside the ball mill, passing to the classification stage making a short circuit to the overflow of the cyclone.The very coarse gold particles as well as the thick flakes of gold do not react favorably to the conventional flotation process; thus studies that have included gravity separation have been conducted to increase the gold recovery. Part of the research included concentrating tables, jigs, and Knelson Concentrators. The Knelson Concentrator proved to be the best selection in terms of metallurgical performance and recoveries considering the throughput and operation conditions of the Tintaya Plant.The gravity concentration circuit with the Knelson Concentrator was commissioned in BHP Tintaya in October 1998, as per the flowsheet shown later on. Presently the global gold production surpasses any estimated expectations.Present efforts are directed towards showing the evaluation and optimization of the different parameters that govern the performance of the Knelson concentrator, as well as illustrating the difficulties and successes throughout the operating period.In the first year of operation 200 tons of gold concentrate have been produced with an average concentrate grade of 320 gramdton, having paid back in full the cost of the automated KC-XD- 48 Knelson Concentrator, the peripheral equipment, and the cost of the installation."

Jan 1, 2002

By P. Foster

Over the past decade there has been a great deal of research into the use of virtual reality (VR) and computer graphics in the mining industry. Much of this has led to developed applications including training simulators and accident reconstruction. One other area where there is considerable potential for virtual reality is that of mining ergonomics. This paper identifies those common ergonomic limitations associated with mining equipment that can be effectively modelled using VR techniques. From this, two simple models have been developed, namely (i) remote control continuous miner operation and (ii) free steered vehicle sight-lines, which demonstrate the practical use of VR in this area.

Jan 1, 2004

By A. Ersoy, M. D. Waller

The principal factors which require consideration in predicting drilling rates are the bit-type, the bit operating parameters and the characteristics of the penetrated rock. A single index is not a sufficient basis for predicting performance. A variety of rock types were drilled in the laboratory with polycrystalline diamond compact (PDC) and impregnated diamond core bits using a fully instrumented drilling rig at different rotational speeds and with a range of weights on the bit. Quantitative determinations of a wide range of textural, mechanical and intact rock properties were also made. Multi-variable linear regression analysis was then used to develop predictive models of rates of penetration from the operating and rock property data. The models have been verified by statistical tests. The analysis indicated that the models for the pin and hybrid PDC bits have potential for practical application. However, although the model for the impregnated diamond bit appears to be reasonable from a purely statistical point of view, it may not be satisfactory for drilling uses as it is based on two measures of rock hardness alone. The application of multiple regression analysis to PDC drilling performance is novel and the technique shows promise for the prediction of rock drillability with PDC bits. The ability of the technique to provide a mathematical characterisation of the performance of new drill bits in specific rocks may prove to be of value to drill manufacturers and users

Aug 1, 1995

By M P. Cipold, J F. Bachmann, C C. Bachmann, J Ha, H B. Wurst

In washability, the objective is to establish the set of maximum possible separation performance criteria for a given mineral feed. The method of choice for this has been the conventional sink–?float analysis. Using traditional sink–float method it is not possible to sample and automatically measure. This fact, as well as time, cost and safety aspects, as well as required and manageable sample size of the sink–float method have prompted the search for a new approach for establishing separation performance criteria. This is especially important as performance levels of separator plants can be maximised if reliable information based on an analysis of washability in conjunction with particle size distribution, elemental constituency becomes available in time. The new method to establish washability and associated performance information utilises at least two measurement technologies concurrently: single energy X-ray transmission and image processing. For porous or very inhomogeneous materials the results can be refined further by using dual energy X-ray transmission and image processing.If used as a standard laboratory device the continuous build-up of the washability curve allows to evaluate the statistical significance of the sample size during measurement.The measuring method can even be improved if it is combined with an automatic sampling system that feeds a continuous and representative particle stream to the analyser. Then the value of the collected data increases considerably since the washability data are additionally available in time to be considered in the control of the process plant. The washability curve can be derived and is continuously updated based on the particles measured during the past time interval. Older curves and results are stored in a database and can be retrieved for later reference. This technology now enables automated sampling and integrated automated measurement, which was previously not possible.This incorporation of an automated washability monitor at a representative sample gives near real-time data that would impinge positively on the profitability of the plant operation. The method was extensively tested using a range of samples with different densities, varying from 1 g/cm3 (coal) to 5 g/cm3 (iron ore).CITATION:Bachmann, C C, Bachmann, J F, Cipold, M P, Wurst, H B and Ha, J, 2017. Inline analysis of washability parameters for process control, in Proceedings Eighth World Conference on Sampling and Blending , pp 213–218 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By S. E. Bretherton

This title introduces the subject I wish to describe to my fellow members, very few of whom, I 'hope, have ever had as much trouble with the smelting of ore containing much zinc, either in the lead blast furnace or the matting furnace, as circumstances have forced upon me: First, for several years in Leadville, Colo., after the sulphide ores containing zinc had been developed with greater depth and were sold to the intereats with which I was connected for smelt-ing in the blast furnace for the recovery of the lead, silver, and gold; then, in New Mexico and Arizona, where the principal source of ore supply for our custom smelter was from miners who sent most of their product in the form of concentrates, which we briquetted and smelted in the blast furnace, producing a matte containing copper, silver, and gold, for which we were paid; together with some zinc and lead, which was penalized if in excess of a maximum base set by the refinery to which we sold our copper matte; last, but not least, my experience in Shasta county, Gal., where for the sake of recovering $13 per ton value in copper, silver, and gold, I have smelted ore containing as high as 40 per cent. zinc (the last 18,951 tons smelted averaged 15 3/10 per cent. zinc) which we not only lost, but which it cost us money to lose. After such an experience, and knowing that, instead of being worth only $13 per ton, such 15 per cent. zinc ore should be worth about $30, including zinc at the present market value, the question of recovering the zinc in a profitable manner from such ore became very interesting to me. During several years' time I sent samples, of from 5 to 1,200 lb. each, to be tested by the different best-known zinc-recovery plants, and experimented with several processes proposed by others for the treatment of such ore, with but little encouragement, until I

Jan 1, 1914

By Rick Frechette, Bryan Ulrich

Representatives from several mining operations in three western states left their mines behind for a day in February to discuss with their peers the issue of water. The event was Knight Piésold and Co.’s Roundtable 2007, held in Elko, NV. It was third such event put on by the company. The issue this year was site-wide water considerations.

Jan 1, 2007