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Experimental petrology may be used to accurately constrain PTX conditions in order to calibrate and understand geologic processes. This method may be used to answer postulated questions, by recreating known geologic conditions and observing changes in the experimental charges. The purpose of this project was to determine the eutectic composition and temperature in the ternary system PbS-FeS-ZnS ¦ (Ag2S), at ambient and elevated pressures and elucidate if the sulfides of the Broken Hill orebody may have been partially molten during highgrade (granulite facies) metamorphism. The study determined the eutectic temperature and composition in the system PbS-FeS-ZnS to be 800¦2¦C and 62.5% PbS, 30.5%FeS, 7% ZnS respectively, at one atmosphere, and the eutectic temperature at 27 kbars was found to be 960¦C¦10¦C, with a eutectic composition enriched in ZnS relative to the one atmosphere eutectic. the addition of lwt.% Ag2S to the system depresses the eutectic temperature to 772¦2¦C at 1 atmosphere and below 810¦5¦C at 5 kbars. The conditions of peak metamotphism for the cental and southern areas of the Broken Hill Block, New South Wales, Australia , lie above the solidus of the PbS-FeS-ZnS-Ag2S system, strongly suggesting that partial melting occurred in the orebody.

Jan 1, 1998

By Jeffrey C. Hillman

The need to recruit locally produced engineers by the South African Mining Industry led to the Engineering Faculty at the University of the Witwatersrand developing a number of academic bridging initiatives for educationally disadvantaged students. The graduation rate achieved during the initial five years of operation by the most successful of these programmes has been on a par with that of al other students but the performance of subsequent intakes has declined to such an extent that the continuance of this scheme could now be at risk. One reason for this reduction in throughput is that many of the applicants for the increasing number of mining bursaries have been more interested in the bursary than the profession and have either failed or dropped out due to a lack of application and motivation. This will have serious consequences for both Wits and the Industry if it continues and some method of identifying unsuitable or suspect applicants needs to be introduced as a mater of urgency. It is recommended that an introductory course be set up at a working mine that would be run under the auspices of Wits, as a joint venture with industry, and include a level of academic input that would provide both bridging needs and certain first year credits. The final form of this course will require extensive consultation with al parties but needs to be completed before the end of 1996. It is further recommended that the advertising and promotion of mining careers be expanded and much improved.

Jan 1, 1996

By N. V. Nayak

Maharashtra State Road Development Corporation Ltd., has initiated a scheme for construction of 55 flyovers in Mumbai in India. To ensure speedier completion of projects several new technologies were adopted to save time without compromising on safety and reliability. Many of the flyovers involved large diameter pile foundations carrying loads ranging from 3500kN to 1375kN. Significant time would have been lost in using conventional load testing procedure to check pile capacity apart from the difficulty in mobilizing the load and the obstruction to site movement and traffic on the adjoining roads. High Strain Dynamic Testing was introduced on the project sites in lieu of static load testing after conducting numerous co-relation studies on various project sites. A total of seven co-relation studies have been conducted till date and based on these data static testing has been replaced by dynamic testing on numerous flyovers. The paper presents the results of such studies. CAPWAP analysis was also conducted on the data to evaluate the percent skin friction and end bearing so as to improve future design parameters.

Jan 1, 2000

By S. Belair, V. Weigel

As a growing mining company, ERAMET is looking for new positions on the strategic metals market. In this context, the Gabonese Maboumine pyrochlore deposit is currently being studied for the recovery of niobium, tantalum, rare earth elements (REE), and uranium. This ore shows mineralogical and chemical characteristics that make it challenging to process by already known practices, from both technical and economic points of view. In this context, ERAMET has developed since 2008 an innovative hydrometallurgical process which has been successfully operated at a pilot plant scale. While the upstream part of the process aims to dissolve the valuable elements in sulphuric acid, the downstream part of the process aims to recover them separately in a marketable form. The focus here will be on the recovery of the REE. The ore deposit contains approximately 1.4% of REE including 87% of light REE and 13% of medium-heavy REE. The challenge in this process lies in the fact that the major elements in the matrix are iron and aluminum. An innovative process has been developed in order to recover all of the REE in these unfavourable conditions, described in this paper.

Jan 1, 2014

By C. D. Shackelford, J. F. Muñoz, M. Vauclin, P. Rengifo, A. Suazo

The results of a field-scale study involving in situ leaching of copper ore tailings using sulphuric acid as the leaching agent, injection wells to introduce the leaching solution and extraction wells to recover the copper-enriched pregnant leaching solution are presented. The study was performed at an abandoned tailings disposal site using a battery of injection and extraction wells. The medium was characterized through the determinations of physical, chemical, mineralogical, and hydro-dispersive properties based on laboratory and field tests, including a tritium tracer test, a pumping test, particle size analyses, and hydraulic conductivity tests. Numerous horizontal strata with different hydraulic conductivities were identified. A previously developed model was used to simulate the leaching of copper ore tailings. Although the study confirms the feasibility of using in situ leaching for recovery of residual copper from tailings deposits, the efficiency of the technology depends significantly on the medium stratigraphy and hydraulic conductivity.

Jan 1, 2001

By Jürgen F. Brune, Alex C. Smith, William D. Monaghan

One of the predominant causes of fires in underground coal mines is flame cutting and welding. These fires can lead to major events such as the explosion that occurred on January 22, 2003 in an airshaft being constructed at the McElroy mine. Six contractors were inside the shaft at the time of the explosion and the explosion fatally injured three and seriously injured three [MSHA 2003]. Understanding the root causes of these fires and explosions will help prevent these types of events from occurring in the future. Fires and explosions require fuel, oxygen and an ignition source (heat). These three items are referred to as a fire triangle. The control of these three items in flame cutting and welding operations is required to prevent fires and or explosions. United States Department of Labor, Mine Safety and Health Administration (MSHA) Reports of Investigation (ROI), MSHA Mine Accident, Injury, and Illness Reports, and the MSHA Mining Industry Accident, Injuries Employment, and Production Data Base were analyzed and interviews and observations with mine workers and welders were conducted to determine the root causes of coal mine fires and explosions caused by flame cutting and welding operations. This paper will discuss the root causes and potential means to reduce the number of fires and resulting fatalities and injuries caused by or due to flame cutting and welding.

By Han Xuanjiang

Through whole analysis of static testing piles information of a teaching building, this paper put for ward that when the ratioes of unload rebound amount to residual deformation and to total settlement reach the maximum, the testing load is selected as allowable capacity of single pile by camparing with the settlement in the practical engineering, it is proved that this method fits to practice, for other several projects, its also available. Therefore non-destructive testing pile method was improved, so all the tested piles can be reused as engineering piles.

Jan 1, 1991

By D J. Brake

There has been a strong trend over the past decade in hard rock mines towards the use of very high powered auxiliary (or secondary) fans; in many mines, the installed power for the secondary ventilation system now exceeds that of the primary ventilation system. This also reflects the trend to use two-stage auxiliary fans pushing air into a single ‘trunk’ duct that in turn splits into multiple branches with multiple outlets feeding multiple workplaces. This often produces a poor result in terms of face flows due to the high resistance, high leakage and badly managed duct outlets, as well as high fan capital and operating (power) costs, which in turn also results in a higher cost for the underground power reticulation/distribution systems. This paper explores the reasons why this trend exists and what ventilation practitioners can do to utilise less expensive systems that simultaneously deliver better workplace conditions. It includes a case study.CITATION:Brake, D J, 2017. Auxiliary ventilation design – why and how mines waste so much power on inferior systems, in Proceedings Australian Mine Vent Conference 2017, pp 27–34 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By Hamid Maleki

Having developed a methodology for estimating mining-induced seismicity resulting from slip along geological discontinuities in 2003, in this paper, the importance of measurements are high-lighted in the study of caving and seismic source mechanisms as applied to mine designs. Geotechnical data is analyzed from four case studies to address cave condition, load transfer, and potential effects on stability and resource recovery in four Utah mines using measurements and observations conducted over the last three decades. Cave conditions are evaluated on the basis of measurements in the gob of a western U.S. operation mining under the massive Castlegate Sandstone and indirectly using the results of measurements and boundary-element modeling at panel boundaries at a mine where strata behave elastically. Together with subsidence measurements and microseismic monitoring, regional caving and load transfer in multiple-panel extractions are addressed while the effectiveness of barrier pillars in reducing stress and seismic response where mining under massive stratigraphic units is analyzed using measurements and three-dimensional computer modeling.

Jan 1, 2006

By P. W. Lotz

Traditionally, bottle roll tests have been used to optimize the extraction process for best gold extraction and recovery. Such tests typically involve exposing the ore to defined reagent concentrations (lime, cyanide and sufficient oxygen) and balance the gold input with recoveries and losses. With mounting pressures to accommodate sustainability issues during development work, it became apparent that much more information would be required on the interactions and kinetic behaviour of solid and solution species during the entire leach process. This information is vital to enable proactive management of critical issues such as cyanide, arsenic, water and tailings management. Inadequate management of these aspects has led to temporary closures and, in cases of non-compliance, to the dynamically changing regulations. MINTEK?s advanced leach facility (ALF) is being developed with the aim of bridging the knowledge gap between the gold leach process and the predictable environmental impacts upon discharge. The facility aims to monitor all parameters of relevance such as pH, Eh, dissolved oxygen, metals, cyanide species, and viscosity during the entire process to enable more informed decisions on practical interventions. The presented set of data reflects first experiences gained from processing a refractory gold ore concentrate. Attempts at optimizing the process were limited due to the developmental nature of the work. Data relating to leaches with differing preoxidation conditions and cyanide staging is presented.

Jan 1, 2009

By J. Um, B. Morin, P. H. S. W. Kulatilake

Development of a three-dimensional mine visualization model for a section of the mine is addressed first. Discontinuity orientation and location information was taken from this visualization model for use in slope stability analyses. Estimated shear strength properties of discontinuities and mechanical properties of intact rock from the rock mass samples obtained from the mine are discussed next. The paper is then focused on the calculated maximum safe slope angles based on the performed kinematic and block theory analyses using the mapped discontinuities at the mine. Finally, the effects of water that exist in the rock mass, tension cracks, slope face inclination, overall wedge height and double benching on factor of safety of wedge stability are illustrated through limit equilibrium slope stability analyses.

Jan 1, 2002

By D. A. Bruce

The Deep Mixing Method is a very valuable tool for combating problems related to in situ soil treatment, improvement, and retention. Many different variations are used throughout the world, and there is a correspondingly rich technical literature on the testing and properties of the treated soil. This paper provides a synopsis of these aspects.

Jan 1, 2001

Changes in reductant and energy inputs which are required to adjust the slag composition in an ilmenite smelter to a higher or lower FeO content are calculated. The calculated changes are based on the assumption that solidification equilibrium with the freeze lining constrains the slag composition to follow a eutectic groove in the TiO2-FeO-TiO1.5phase diagram. Calculated equilibrium conditions along the eutectic groove are presented, and form the basis of the calculations. The inputs of energy and carbon need to deviate strongly from the steady-state values to adjust the slag composition. The inputs required at any given time depend on the desired rate of change of the slag composition, and the current slag composition. The steady-state relationship of a change in energy input of 5 kWh corresponding to a 1 kg change in carbon input also holds for the changed inputs during transient changes in FeO content. Keywords: Ilmenite smelting, freeze lining, solidification, eutectic

Jan 1, 2003

By C. Dinis da Gama

Because of the growing importance of back analysis for the interpretation of rock slope failures, particularly in open pit mines, it is suggested a methodologic sequence of activities for dealing with those problems. The principal mathematical tools for the interpretation of the most common mechanisms of slope failures are reviewed, including methods of stress and strain analysis, which seem to be more powerful for parametrization studies, and for developing more realistic explanations of slope behaviour, such as the measurement of displacements. An application of those methods is described, using slope failures detected in a Brazilian uranium mine (Cercado), thus providing reliable shearing strength parameters for the rock mass discontinuites, which were used in the final pit design. The concept of using backanalysis results to supply input data for pit design was implemented by means of the excavation of an experimental trench within mine limits, where specific instruments were installed, and several slope failures were monitored and backanalysed, in order to yield information about sliding mechanisms in the future open pit.

Jan 1, 1983

By B. McLaughlin

Agnico-Eagle started sinking the Penna Shaft in 1995 with a hoisting plant capable of hoisting 1800 t/d from a 2240 m deep shaft. Exploration success led to the installation of a hoisting plant capable of extracting 4500 t of ore and 1800 t of waste per day from a depth of 2210 m. The introduction of a new rope selection factor, permitting a safety factor of 4.0, represented the breakthrough required for a cost-effective project. This paper describes the process taken to introduce the new rope selection factor and its impact on the original plant.

Jan 1, 2004

Gold mines produce unique water treatment requirements. This paper focuses on case studies of innovative processes used for treatment of water resulting from gold mining and processing. The case studies include treatment of mine dewatering water for beneficial application from an Australian gold mine, Bendigo Mining, as well as treatment for arsenic removal of tailings water from mining and processing at Goldcorp mines in Canada. Gold mining can often require dewatering to prevent groundwater seeping into and flooding the mine workings. Gold mining and processing often accumulate wastewaters in a tailings dam. The mine water can contain contaminants such as dissolved salts, iron, arsenic, manganese, heavy metals and odorous sulfates. Environmental discharge requirements as well as community needs for water drive mine operators to consider the most appropriate water treatment process. Treatment of gold mine water can require processes including oxidation, pH adjustment, coagulation, flocculation, clarification, further oxidation/adsorption of specific metals such as manganese, filtration, salt reduction utilising reverse osmosis, brine minimisation and other innovative technologies. These processes are discussed through the case studies with examination of the specific treatment process that is required. This paper uses real case studies of gold water treatment processes to explain and examine the technology and the reasons for designing specific processes. The focus is toward explaining innovative processes where the water is used for sustainable environmental discharge or treatment to a quality that can be beneficially used by the local community.

Jan 1, 2007

By C. R. Stephan

Explosion-resistant seals in underground coal mines isolate the environment within the sealed area from the active workings of the mine. The current United States Title 30 Code of Federal Regulations (CFR) requires these seals to be constructed of solid concrete blocks. The CFR also allows for alternative methods or materials to be used to create a seal if they can withstand a static horizontal pressure of 138 kpa (20 psi), provided the method of installation and the material used is approved in the ventilation plan. The purpose of this report is to identify those explosion- resistant seals that have been tested and meet or exceed all the requirements of the CFR.

Feb 24, 1997

By Fanke Meng

Electrolyzing oxides of titanium, aluminum and niobium could prepare high-Nb bearing TiAl alloy (Ti-45Al-9Nb) at 1500°C. The chosen electrolysis voltage is 3.5V, which is lower than reducing voltage (~4.7V) of electrolyte CaF2, but higher than that of titanium, aluminum and niobium oxides. The investigation shows that compared with traditional methods, this method for preparing high-Nb bearing TiAl alloy is of many advantages such as few steps, friendly environment, low energy consumption, low cost and high current efficiency.

Jan 1, 2009

By Andrew Peterson

The Maine Department of Transportation offered this challenging design-build project for a new, 12-span, bridge over the Kennebec River in Bath, Maine. This structure would be built to replace the existing Carlton Bridge connecting the village of Bath, Maine to neighboring Woolwich, Maine. The design build team of Flatiron Structures, Inc., and Figg Engineers, Inc., elected to design and build a segmental concrete bridge. Site conditions dictated that this bridge would be supported primarily on deep foundations. Case Foundation Company joined the project team in the winter of 1997 to install twenty-two, eight foot diameter drilled shafts. The drilled shafts were designed with 8' diameter, permanently cased shaft sections and 7.5' diameter rock sockets. Shaft lengths ranged from 20' long near the river's edge to 100' deep in the middle of the river. Rock socket lengths ranged from 12' to 30' deep. Two Osterberg Cell load tests were conducted on production drilled shafts. Figg Engineers utilized the results of the load tests to "fine-tune" the rock socket design during construction of the drilled shafts. Construction of the drilled shafts proved to be very challenging and called on every member of the design-build team to work together throughout the project. One of the most challenging aspects of this project was in the installation of the 8' diameter permanent casing and drilling of the rock sockets. Early in the project, it became apparent that the top of bedrock was broken and unstable. This condition limited the advancement of the permanent casing and the affect of a "seal" at the top of rock socket. As a result, as the rock socket was advanced, loose material spilled into the hole and stopped progress of the socket. In order to resolve this problem, the design-build team developed a redesigned drilled shaft which included the installation of a steel sleeve to seal off the unstable rock formation. Following installation of the sleeve, the rock socket diameter was reduced to 7' diameter and advanced additional length to achieve required design capacity. All drilled shafts were installed with equipment supported on floating barges. Water access, along with the long shaft lengths and very hard bedrock required the use of cranes and drilling equipment that far exceeded the requirements of typical drilled shaft projects. This paper will discuss the relationship between design, construction, and equipment utilization on this challenging design-build project. [ ]

Jan 1, 1999

By I. Stanculescu

The consolidation of thick and very compressible soil deposits by stone columns associated with cast-in-place plain concrete columns, has been performed for shallow foundations of some heavy industrial structures. The reduction of settlements and increase of soil bearing capacity were thus ensured as a result of soft soil interaction with stone and concrete columns. The results of model tests and in situ large scale applications are presented. A calculation procedure is also suggested for foundation bases improved by the proposed method.

Jan 1, 2010