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By J. B. Kitchin

"The design of conveyor belting for use in mines poses problems to the manufacturer that are unique. The challenge to be met is that of the production of a conveyor belt which can withstand use and misuse in an environment that may differ vastly from one country to another, and even between one mine and its neighbour.The development of a product to meet such varying requirements necessitates a protracted program of trials, both in the laboratory and in the field; a new successful development, the only criterion, can be said to have been achieved only after very long-term usage under actual, deliberately chosen, arduous mining conditions.New developments in conveyor belt construction can never stop, no more than can developments in new and advanced mining techniques. A new problem is set-an answer must be found. Some of the problems are noted here, and answered where possible, in what must after all be little more than an excursion into a very comprehensive and detailed subject."

Jan 1, 1967

The New Technology of Enrichment of a Fine Low-Grade Tungsten from Complex Multi-Metallic Ore

Sep 13, 2010

Physical/Chemical Treatment of Mercury-Contaminated Wastes from Former Chlorine-Alkali Electrolysis Plants - Application of Flotation Technologies in Soil Washing Plants

Sep 13, 2010

In the last two years the Commission for the Environment has received four Environmental Impact Reports (EIR) for Audit and has been or is involved with at least four environmental impact assessments (EIA) related to mining. The EIRs have included Weavers Coal Mine, the Monowai-Maratoto mining proposal, the Martha Hill mine and the Wainui Road Mill. The EIAs are related mainly to coal fields in the Waikato but also included a further EIA on Martha Hill.

Jan 1, 1986

By J. E. Chilton

The National Institute for Occupational Safety and Health (NIOSH) has conducted research to determine the influence of mining machine-mounted scrubbers on airflows and methane concentrations at the face when blowing ventilation systems are used. Tests were conducted in a full-scale ventilation gallery with a model mining machine that simulated airflow created by a dust scrubber. During the tests, ultrasonic anemometers were used to measure airflow speed and direction at several locations near the face. For the same test conditions, methane was released from the face and gas concentrations were measured at 21 locations above the machine using fixed point methanometers. Changes in airflow speed and direction are correlated with scrubber airflow and the measured methane distribution above the mining machine. The research results showed that operation of machine-mounted scrubbers improved face ventilation when blowing ventilation is used by increasing both the intake flow and the quantity of air reaching the face.

By S M. Zhang, Y X. Han, J Liu, Y J. Li

"Compared with conventional roasting and magnetic separation processes, higher reduction temperatures and stronger reducing atmospheres are used in reduction technologies to reduce iron oxides to metallic iron, which is often liberated during reduction and amenable to magnetic separation. Reduction and magnetic separation of an Australian refractory iron ore was therefore studied as a function of reduction temperature, time and coal addition. It was found that during reduction, the particle size of the reduced iron increased with reduction temperature and time. Subsequent magnetic separation tests were further conducted on the reduction products. A reduced iron powder with a Fe grade of 85.67 per cent was obtained at a Fe recovery of 87.82 per cent under optimum reduction conditions where a metallisation rate of 85.82 per cent was achieved. The mechanism involved in reduction is discussed based on XRD and SEM examinations.CITATION:Han, Y X, Liu, J, Li, Y J and Zhang, S M, 2013. Upgrading an Australian iron ore by reduction and efficient magnetic separation, in Proceedings Iron Ore 2013, pp 397-402 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 12, 2013

By K. Short

Over the past several years, the mining and minerals market was overloaded with discussions around reviving mature terminologies like distributed control systems (DCS), programmable logic controllers (PLC), and the ?new comers?: hybrid control systems (HCS) and programmable automation controllers (PAC) and, in parallel, which technologies would be more appropriate for mining and mineral processing applications. Ten years ago, a careful comparative analysis would make more sense. Control approaches had very distinctive differences where users needed to choose the right approach.

Jan 1, 2012

By Rob Thomas

Pre-driven recovery roads are used to speed up the longwall recovery process by reducing bolt-up requirements and by improving ground conditions on the face during the removal of the powered supports. To lower the geotechnical risks associated with the use of pre-driven recovery roads, and so improve its overall acceptance in the industry as a viable alternative to more conventional, potentially difficult and costly longwall recoveries, this paper outlines (i) a geomechanical model for the use and design of pre-driven recovery roads, (ii) an updated version of the worldwide database on pre-driven recovery roads, (iii) a summary of the various methods of holing a longwall into a pre-driven recovery road and (iv) a series of relevant ground support and strata management guidelines.

Jan 1, 2008

By David H. Searle

This paper will discuss the common trends existing in various Canadian jurisdictions for the closure and reclamation of mines. Included will be a discussion of the requirement to post security as well as its form and how security is calculated and refunded. Reclamation can no longer be left to the end of mine life. Progressive reclamation must occur throughout mine life and must be part of the mine plan from the beginning.

May 1, 2006

By L. L. Seigle

Free energies, heats, and entropies of mixing of solid Fe-Au alloys have been measured by the galvanic cell method between 800° and 900°C. A positive deviation from Raoult's law and a large excess entropy of mixing were observed, both attributable to lattice distortion caused by the disparity in component atom sizes. Since the terminal solid solutortiontions are not regular, thermodynamic properties computed from the location of the mis-cibility gap do not agree well with measured quantities. The electromotive force data suggest some changes in the existing Fe-Au phase diagram. ALTHOUGH a considerable amount of information has been accumulated about the thermodynamic properties of metal solid solutions which exhibit negative deviation from Raoult's law, particularly those in which ordering occurs, relatively few experimental measurements have been made on solutions with positive deviation. This is due to the infrequency of broad homogeneous regions suitable for experimental measurement in solutions of this type, since any marked positive deviations from ideality lead to restricted solubility and the formation of miscibility gaps. Thermodynamic data reported in the literature for such systems have usually been calculated from the location of the miscibility gap boundaries under the assumption that the entropies of mixing are ideal, i.e., the terminal solutions are regular.' One of the few binary systems with both positive deviation and a wide homogeneous range in the solid is the Ni-Au system. A recent investigation of solid Ni-Au alloys' revealed that the entropies of mixing were much larger than ideal and consequently thermal data computed from the phase boundaries assuming regular solutions were seriously in error. Theoretical considerations put forward by Zener indicated that high entropy values should generally be associated with systems possessing a miscibility gap in the solid, when this is due to differences in the size of component atoms. These facts suggest that the regular solution assumption is a poor approximation for many solid solutions with positive deviation and that reliable thermodynamic data generally cannot be obtained by conventional methods from the location of miscibility gap boundaries. The Fe-Au system, Fig. 1, resembles the Ni-Au system in certain respects. The presence of a miscibility gap in the solid indicates a large positive deviation from ideality, but there is nevertheless an extensive single phase region suitable for experimental measurement. The following investigation of solid Fe-Au alloys was carried out in order to obtain additional data on the thermodynamic properties of metal solid solutions with positive deviation from Raoult's law and to further compare thermodynamic data computed from miscibility gap boundaries with those measured experimentally. Experimental Method The thermodynamic properties were derived from measurements of the potential developed between pure solid iron and Fe-Au alloys in a high temperature galvanic cell. The experimental apparatus and technique were the same as those used for the Ni-Au alloys and described in a previous report.' Cell electrodes were 1/16 in. diam rods swaged from chill-cast ingots and annealed for one week at 850°C. The alloys were prepared by melting fine gold granules under argon with pure iron obtained from the National Research Co. The cell electrolyte was

Jan 1, 1957

North American Coal is a subsidiary of NACCO Industries. Originally founded as Cleveland and Western Coal in 1913, North American Coal took its present name in1925. Today, North American Coal is one of the 10largest coal producers in America, mining about 32Mt/a (35 million stpy). The company mines primarily lignite for electric utilities. Its current operations are in North Dakota, Texas, Louisiana, and Mississippi. In addition, North American Coal’s Florida operation provides dragline mining services for quarries that produce more than 18Mt/a (20 million stpy) of limerock. With more than 1.8 Gt (2 billion st)of bituminous and lignite coal re-serves in the United States, North American Coal constantly seeks new technologies to keep its operations modern, productive and cost competitive.

Jan 1, 2004

By S. Addie

In the early 1990’s the British Columbia (Canada) mineral industry frequently discussed the need to participate in, and compromise with, public environmental interests in order to ascertain long-term stability. However, as the decade progressed the mineral industry withdrew from almost all meaningful public participation. As government protected areas policy in the past year has illuminated, there is a continued need for long-term land access stability. This paper historically analyses the public engagement policies of the British Columbian mineral industry while it participated in long-term consensus-based multi-stakeholder land-use planning processes. From this analysis the paper recommends that the mineral industry reengage the public and institute a new working relationship with environmental advocacy groups so as to ensure British Columbia becomes the most sustainable mineral producing jurisdiction in the world.

Jan 1, 2011

By Oliver Zach

To know as much as possible about the condition of the refractory material (lining thickness, slag layer, build ups, ...) in an high temperature furnace is very important due to the safety and economic impacts. The new CONSCAN system offers the possibility to measure the inner surface of an furnace, and based on this results to calculate the thickness of the refractory lining, slag layer, build ups,.... The CONSCAN System provides this results as figures and graphics. This system is also working under hot conditions so it is not necessary to cool down the furnace. Based on these results the process control and the refractory lining concept could be optimized for maximum campaign life of the furnace.

Jan 1, 2006

By J. Werfling, J. R. Kiehl

SUMMARY: The effects of blasting on structures are assessed on the basis of the maximum amplitudes of the occuring vibration velocities. If the standard values in the German Standard DIN 4150 are not exceeded, damages to structures are not to be expected. The estimation of the maximum vibration amplitudes is usually based on experience or on emperical formulae. However, a comparison of expected with measured values shows that these estimations are not conservative, particulary in case of small distances between blasting locations and structures. More reliable predictions are possible on the basis of numerical analyses, which simulate the three-dimensional propagation of waves with consideration of the geomechanical and geometrical conditions. In addition to the expected velocities, these analyses also allow the determination of stresses resulting from dynamic loading. If the dynamic stresses are known, the effects of blasting on structures can be predicted. ZUSAMMENFASSUNG: Die Auswirkungen sprengbedingter Erschütterungen auf bauliche Anlagen werden in der Praxis auf der Grundlage der Maximalamplituden der auftretenden Schwinggeschwindigkeiten beurteilt. In der DIN 4150 werden Anhaltswerte angegeben, bei deren Einhaltung Schäden von Gebäuden nicht zu erwarten sind. Die Abschätzung dieser Schwing-geschwindigkeiten erfolgt meist auf der Grundlage von Erfahrungswerten oder empirischer Formeln. Der Vergleich der prognostizierten Werte mit Meßergebnissen zeigt jedoch, daß diese Ansätze insbesondere dann, wenn die Abstände zwischen den Sprengorten und den Gebäuden gering sind, nicht konservativ sind. Zuverlässigere Prognosen sind auf der Grundlage von numerischen Berechnungen möglich, in denen die räumliche Ausbreitung von Erschütterungen unter Berücksichtigung der geomechanischen und geometrischen Verhältnisse simuliert wird. Mit derartigen Berechnungen können die zu erwartenden Schwinggeschwindigkeiten und die aus der dynamischen Beanspruchung resultierenden Spannungen ermittelt werden. Dies ermöglicht Aussagen über die Auswirkungen sprengbedingter Erschütterungen auf Bauwerke. RÉSUMÉ: Les conséquences de vibrations résultantes d'explosions pour des bâtiments sont estimés dans la pratique à partir des amplitudes maximales des vitesses d'oscillation. Dans la norme allemande DIN 4150 des valeurs d'orientation sont données, avec l'observation desquelles de dommage à des bâtiments n'est pas à présumer. Ces vitesses d'oscillation sont estimés généralement à partir de valeurs d'expérience ou de formules empiriques. La comparaison des valeurs prédits avec des résultats de mesures montre cependant que ces hypothèses ne sont pas conservateurs, en particulier si les distances entre les lieux de sautage et les bâtiments sont petites. Des prédictions plus fiables sont possibles à partir de calculs numériques, dans lesquelles la dissipation spatiale de vibrations est simulée en considération de la situation géoméchanique et géométrique. Avec tels calculs les vitesses de vibration à présumer et les contraintes résultantes de l'effort dynamique peuvent être établies. Cela permet de constater sur les conséquences de vibrations résultantes d'explosions pour des bâtiments.

Jan 1, 2003

By William W. Edgerton

The California Department of Transportation (Caltrans), the Contra Costa Transportation Authority (CCTA), and the Alameda County Congestion Management Agency (Alameda CMA) are involved in a unique partnership on the planning and design of the fourth bore of the Caldecott Tunnel, located on State Route 24 in Alameda and Contra Costa counties. The project will add a two-lane bore north of the existing three bores. The project will alleviate traffic congestion in the non-peak direction. This paper provides background on the existing facility, summarizes the need for the new fourth bore, describes the proposed improvements, sets forth the approach for project delivery, and lists some of the challenges that are expected during construction.

Jan 1, 2008

By Jose A. Delgadillo

The hydrocyclone problem has been a challenging task for the last 30 years. In the 80’s and 90’s Computational Fluid Dynamics solution to this problem began to appear. These were unsuccessful due to over simplification. In the past 3 dimensional solution with ?-e model and Reynolds Stress Model have been published. In this paper RSM and ?-e models are compared with velocity profiles measured in 75 mm and 250 mm diameter hydrocyclones. It is shown that results are not satisfactory with RSM or ?-e and that a model called Large Eddy Simulation is needed to describe velocity profile evolution and size classification.

Jan 1, 2005

By J. A. Rusnak, M. M. Gadde, S. S. Peng

In situ stresses are one of the key inputs to a successful underground excavation design. Because of the complex mechanisms involved in arriving at the current state of stress at a point in the Earth’s crust, often the only reliable way of estimating in situ stresses is by actual measurement. In the United States coal mines, overcoring relief method is by far the most popular technique used for estimating the virgin stress field. Typically, for stress measurement with overcoring, a vertical borehole is drilled into the roof or floor of an underground coal mine opening to a certain distance and change in borehole diameter is monitored at multiple points along the length of the hole when this borehole is overcored. For the measured stresses to represent the pre-mining stress field, the measurement points should be located beyond the influence zone of the mine opening. Actual data from several US coal mines have been collected to check if the measured stresses by overcoring represent true in situ stresses. The data indicate that most of the stress measurements were within the excavation influence zone. A three-dimensional numerical modeling methodology was applied to one of the collected cases to correct the measured stresses for the excavation influence. The modeling approach demonstrated the usefulness of integrating numerical modeling into a stress measurement program to estimate ‘true’ in situ stresses.

Jan 1, 2006

It is crucial to reestablish a domestic rare earths minerals production industry to help secure the Nation's clean energy future, reduce the U.S. vulnerability to material shortages related to national defense, and to maintain our global technical and economic competitiveness. Given that the Chinese dominance of the rare earths market has adversely impacted supply stability and endangers the United States and its allies' assured access to key materials, rare earths should qualify as materials either strategic or critical to national security. Further, the U.S. government should facilitate the reintroduction of a globally competitive rare earth industry in the U.S. Realization of this objective requires: ? Developing domestic processing capability so that the U.S. is not primarily dependent on China as a source of rare earth ore, and almost exclusively dependent of China for processing of the ores. ? Providing a mechanism where access to Federal lands for rare earth exploration and extraction is possible, and ? Training engineers to design and operate rare earth ore processing facilities

Jan 1, 2011

By Wendy L. Mathieson

The Bonneville Power Administration (BPA) will build about 500 miles of new 500-kV transmission lines in the next 5 years. Many new lattice towers will be built in remote locations or in environmentally sensitive areas. Therefore, micropile foundations were designed that could be installed in remote areas, in variable subsurface conditions, and in a manner that would reduce excavation volumes and potential erosion concerns. Typical lattice tower foundation axial loads range between 75 and 1,500 kips (300 to 6,700 kilonewtons [kN]) per leg, with uplift loads being slightly less than compressive loads. Lateral loads range from 5 to 320 kips (20 to 1,400 kN) per leg. Full-scale axial and lateral load tests were conducted in geologically representative soil units during the micropile design for the 9-mile-long (14-kilometer [km]), Kangley-Echo Lake transmission line that extends through a protected watershed east of Seattle, Washington. Micropile foundations for single and double circuit suspension and dead end towers were designed using these load test data.

Jan 1, 2004

By William H. Hamilton

This report describes the results and conclusions of the development and evaluation of a unique concept for a lightweight air powered drill tool for probe drilling in anthracite mines. A concept model of the lightweight air powered tool was constructed and evaluation testing conducted at the Kocher Coal Company Porter Tunnel Mine. The unique anchoring method proved to be extremely satisfactory and the overall light-weight air powered drill tool concept proved feasible. Based on the results of the concept model testing, two prototype production units were designed and manufactured. These prototype units proved to meet all of their design requirements of lightweight, portability, drilling controllability, structural integrity and miner acceptance. The need for a better bit and drill steel system, however, became evident during the testing program and recommendations are made for further investigation and development of a bit and drill steel system suitable for this application.

Jan 1, 1979