Search Documents

By Voorhees JS, Bureau G

To operate a mine in California requires compliance with State environmental regulations, including assessment of risks and associated financial assurances for postulated worst case catastrophic event scenarios. Carson Hill Gold Mine, an open pit, heap leach operation, completed new risk assessment catastrophic event analyses in 1988. The risk assessment was performed at the same time that a new leach site (Leach Site 3) was being designed. Leach Site 3 is located about 400 m upslope of New Melones Reservoir, which is a public recreation facility and a source of drinking water. Release of leachate (pregnant solution) or ore containing cyanide and metals from Leach Site 3 into New Melones Reservoir was considered to pose the largest risk of environmental damage.Flow failure of the ore heap, potentially induced as a result of liquefaction of the saturated portion of the ore, and/or overtopping of the leach site containment embankment due to excessive precipitation were found to be the most plausible leachate release scenarios. Yearly combined probabilities of various downstream release volumes were estimated. The release volume corresponding to a yearly probability of 0.05 percent was then used to estimate potential environmental impacts and mitigation costs. The costs include earthwork to restore the geometry of the ore heap and repair the fill slope below the Leach Site 3 containment, and impacts on New Melones Reservoir.

Jan 1, 1990

By C Zhang, G Si, J Oh, X Zhu

The presence of rock joints has a huge impact on the strength, deformability, and permeability of fractured rock masses by providing surfaces of weakness on which further deformation are more prone to occur, and by serving as the major channels of water flow due to low matrix permeability. In earlier studies, water flow-through rock joints is often assumed as laminar flow between two ideal smooth parallel plates, and the well-known cubic law was derived and widely used to characterise the hydraulic behaviour of rock joints. However, natural rock fractures are irregular and of spatially varied aperture. Thus, the concept of equivalent hydraulic aperture was introduced to modify the cubic law. Numerous works have been conducted on the relation between hydraulic aperture and mechanical aperture incorporating various geometrical parameters. The surface roughness is one of the most sensitive factors for water flow-through rock joints. The aperture distributions are irregular in natural roughed fractures relative to the parallel plates. Barton et al (1985) and Olsson and Barton (2001) incorporated the joint roughness coefficient JRC in evaluating hydraulic aperture and proposed an empirical equation based on fluid flow tests. However, their equations do not conform to the dimensional consistency. Many other researchers (Zimmerman and Bodvarsson, 1996; Xiong et al, 2011; Li et al, 2019) considered aperture distributions in their equations. But the aperture distributions change during shear was always neglected. The contact of rock joints also has a significant impact on the hydro-mechanical behaviour of rock joint, since fluid tends to flow-through a rough joint along connected channels while bypassing the contact obstacles with tortuosity. Nonetheless, previous research mostly considered joint roughness or aperture changes based on 2D joint profiles, while the contact and tortuosity based on 3D surfaces were often overlooked. Only a few works have been made on quantifying the effect of contact area on flow behaviour (Walsh, 1981; Zimmerman et al, 1992; Zimmerman and Bodvarsson, 1996; Yeo, 2001), and mostly ignored contact area change induced by shearing and the associated impact on flow behaviour. Summarily, the quantification of fracture geometry effects on water flow in single rock joints still needs further investigation, especially when considering coupled shear-flow processes. This paper, therefore, aims to study the impacts of contact area and aperture distributions of the single rock joint on the flow behaviour. The evolutions of contact area and aperture distributions induced by shear are considered. Then, an improved model for estimating the hydraulic aperture with the mechanical aperture incorporating the above factors is developed. Finally, a series of shear and shear-flow tests are conducted on artificial joint samples and the model performance is verified by comparing against the results of experimental tests.

Nov 29, 2022

As the mining sector increasingly embraces the sustainability agenda, and implements thorough environmental reporting in support of its case for a continued æsocial licence to operateÆ, there is a need for ever-clearer metrics for key areas of impact. It is clear that natural waters are both the predominant pathway and main recipient of the environmental impacts of mining. A new approach to summarising the impacts of mining operations on water quantity and quality is proposed, adapted from an existing generic framework, which is increasingly used to quantify the æwater footprintsÆ of cities and nations. This includes both direct water use and ævirtual waterÆ use, implicit in goods and services used by the mine. In contrast to the existing formulation of æwater footprintÆ, it is here argued that it makes hydrological sense to express the water footprints of mines in areal terms, as equivalent catchment areas. It is also important in the mining sector to capture systematic changes in the scale of impact, which can be anticipated and predictively quantified over the full life cycle. This includes the essentially infinite post-closure phase, during which æremanent water consumptionÆ occurs, either through physical water loss (eg by evaporation from pit lakes) or by ongoing contamination of sizeable flows of natural waters. Methods for assessing the water footprints of mines are now available, and the time is increasingly ripe for them to be applied in earnest in environmental reporting. An example application to a mine in a humid subtropical area of South America is presented. In that case, the mine site itself extended over 106 ha, whereas the maximum water footprint exceeded this by a factor of 27. Although the water footprint can be expected to decline by a factor of ten immediately after closure, sustained evaporation from pit lakes and tailings dams with water covers will gradually increase the remanent water consumption rate, such that the final post-closure water footprint remains about 25 per cent of that encountered during the peak of mining.

Jan 1, 2006

By R Trueman

An improved ability to predict dilution for narrow vein deposits enables more accurate economic comparisons between mechanised longhole stoping and other narrow vein mining methods, as well as reducing uncertainty surrounding dilution estimates for deposits at the prefeasibility/ feasibility stage. This paper proposes narrow vein dilution prediction and minimisation strategies for both greenfield sites and operating mines, respectively. The narrow vein dilution method (NVD method) is a tool for more accurately predicting longhole narrow vein dilution. The method is based on a new concept called benchmark stoping width. Benchmark stoping width is based on probabilistic analysis of overbreak distributions from a typical longhole narrow vein mine. The premise for the NVD method is that dilution associated with longhole stoping can be predicted using the benchmark stoping width. In addition to dilution prediction, the NVD method also includes strategies for narrow vein dilution minimisation generally, including; filling, cablebolting, stress relaxation, extraction sequencing and blast overbreak.

Jan 1, 2008

By i, A Shirbazo, S Saydam, S Ata, H L. Ram, B Li

The integration of internet technology into industrial sectors has significantly accelerated the adoption of Internet of Things (IoT) devices, transforming communication, data aggregation, and information distribution. The mining industry has embraced this evolution by deploying IoT devices and advanced technologies like autonomous robots and sensors to enhance operational safety. These sensors enable real-time data transmission and continuous monitoring of key parameters, providing decision-makers with timely insights. However, the interconnected nature of these devices has introduced complexities, resulting in inconsistencies across operations. Addressing these challenges, this research explores the application of modern digital principles to the mining industry through the Reference Architecture Model Industry 4.0 (RAMI 4.0). RAMI 4.0 offers a robust framework that integrates digital and physical systems, promoting data transparency, interoperability, and decentralised decision-making. This study aims to briefly introduced framework designed for the unique challenges of mining operations, leveraging the latest digital technologies. The lack of standardisation in the mining sector highlights the need for a comprehensive approach to tackle issues such as interoperability, scalability, security, safety, and repeatability. Establishing standard procedures can ensure smooth interaction between connected devices, ultimately enhancing operational efficiency in the growing IoT ecosystem within the mining industry. Introducing a well-defined reference architecture like RAMI 4.0 can streamline management processes and improve operational efficiency in mining. By adopting this framework, the mining industry can effectively navigate the challenges of digital transformation, leading to a more connected and resilient future. The study concludes that RAMI 4.0, with its structured approach, can significantly enhance the efficiency and productivity of mineral processing operations, fostering sustainable growth in a digitally driven industrial landscape.

Sep 1, 2024

In order to do the discharge estimation better, it is valuable to find out appropriate formulas for estimating discharge in various pits, based on accumulating data, summarizing discharge patterns applying optimum seeking method and principle, by seeking redical exponent with help of the method of exhaustion, as well as testing and making statistics, in accordance with the quality standards established by our practical experience.

Jan 1, 1988

By B B. Beamish, M S. Kizil

The processes that take place during the development of a heating are difficult to visualise. Bulk coal self-heating tests at The University of Queensland (UQ) using a two-metre column are providing graphic evidence of the stages that occur during a heating. Data obtained from these tests, both temperature and corresponding off-gas evolution can be transformed into what is effectively a video-replay of the heating event. This is achieved by loading both sets of data into a newly developed animation package called Hotspot. The resulting animation is ideal for spontaneous combustion training purposes as the viewer can readily identify the different hot spot stages and corresponding off-gas signatures. Colour coding of the coal temperature, as the hot spot forms, highlights its location in the coal pile and shows its ability to migrate upwind. An added benefit of the package is that once a mine has been tested in the UQ two-metre column, there is a permanent record of that particular coals performance for mine personnel to view.

Jan 1, 2005

By Waddell S

A new procedure has been developed for the direct determination of metals loaded on activated carbon. It involves preparation of a suspension of the powdered carbon in water, followed by direct sampling of the suspension with a micropipette,and analyses by atomic absorption spectroscopy using carbon rod atomization. Advantages of the method include the simplicity of sample preparation and the ability to provide a complete metal analysis in 1 - 2 hours. This enables carbon-in-pulp operators to respond quickly to changes in plant efficiency arising from carbon fouling. The successful application of the method has been demonstrated for gold, copper, nickel and iron. Other elements to be surveyed include calcium, magnesium and silicon.

Jan 1, 1984

Many problems result when coal mine shafts are built in complicated geological conditions and serious shaft lining ruptures have often occurred in the eastern part of China since 1987. Grouting is applied as one of the major measurements for shaft lining ruptures. However, as the general location of reinforcement grouting for shaft lining is deep in or near the bottom aquifer, while using cement grout as the grouting material, the grouting mostly belongs to fracturing grouting in deep alluvium. In these conditions, the mechanism and behavior of fracturing grouting has not yet been understood. From these points of view, this paper describes the mechanism of shaft lining rupture and fracturing grouting and then discusses the effect of grout injection on the stability of shaft lining by means of numerical analysis and field data obtained so far.

Dec 6, 2010

By S Sabanov

Supplementary sampling of particulate mass concentration, the number concentration and the average particle diameter of nanoparticles using a TSI Dust-Trak DRX Aerosol Monitor, Naneos Partector 2 has been conducted. The aim of this study was to evaluate suitability of the instrument for long-term monitoring of diesel particulate matter (DPM) at conditions of polymetallic mines. Sampling was conducted in an area of the active ore heading, requiring the use of a diesel-powered face haul-age loader R1700 and a mine truck Caterpillar AD-45. The sampling was done for 126 minutes at a distance of 30 metres from the mine face. Results of this field work can be used to expand the sampling program to other mines. Expected outcomes of this study are to develop costeffective DPM control strategies, improve mine ventilation, and protect mineworkers’ health.

Oct 12, 2022

Comparison of the Zadra, Anglo-American and organic solvent procedures for desorption of gold from activated carbon loaded in carbon-in-pulp gold circuits indicates that the Anglo American and the organic solvent procedures are considerably more effective than the commonly used Zadra procedure. Organic solvent elution procedures, particularly those using acetonitrile and acetone, can provide effective gold elution and very high concentrations of gold in eluate solutions. The operational simplicity and effectiveness of the Anglo American procedure would appear to make it the most satisfactory procedure available at the present time but this may change as the solvent elution procedures become better developed. INTRODUCTION The carbon-in-pulp technique has been introduced into the gold processing industry to by-pass the often lengthy CCD and filtration steps required in the conventional Merrill Crowe cyanidation procedure for gold recovery. Adsorption of gold on to carbon is also a valuable technique for recovering trace amounts of gold from low level waste streams from conventional processing procedures.

Jan 1, 1982

The application of cheap robust microprocessor based units to achieve monitoring and control in an underground mining environment is described. The functional layout of the programmable controller and the methods of multiplexing and processing information from local and remote sources are examined as are features for refrigeration plant control.High noise immunity communication to a remote micro computer uses existing telephone lines and enables display and print of essential data. The development of this system then leads to applications in monitoring compressed air, ore transport and underground fires.In conclusion, the problems of data presentation to different levels of management and the future philosophy of a central multi-reporting system are discussed.

Jan 1, 1985

By B P. Banerjee, D Patra, S Raval

Roof bolts are an essential component of roof support systems in underground mines. They are used to provide structural support to the roof of the mine and prevent it from collapsing. Therefore, it is imperative to perform regular assessments of these roof bolts to avert any hazards. Manual investigations of roof bolts are done by surveyors in underground mines, which is extremely timeconsuming and challenging due to the low-light conditions in underground mines accompanied by stringent mine access rules. To this end, automated recognition of roof bolts in 3D point cloud data obtained through laser scanning in underground mines serves as a potential solution to aid roof bolt monitoring. With the continuous advancements in laser scanning-based 3D data acquisition systems, the feasibility of making such surface estimations from 3D point cloud data has increased severalfold.

Sep 1, 2024

By J P. R de Villiers

The Vanderbijl Park sinter plant in South Africa was investigated to determine the reason for the production of very fine sinter not acceptable as feedstock for the blast furnace. A procedure was designed to generate representative samples and to prepare the samples for chemical and mineralogical analyses. Results from a mineral analyser showed that the samples are extremely heterogeneous and therefore the sampling and sample preparation methods had to be tested in order to produce representative samples. The high production capacity at the sinter plant could also give rise to sampling errors. The method designed involved sampling of the conveyor belt at the sinter plant every four hours for the duration of three days. The samples were then milled and split into smaller sections appropriate for analysis. X-Ray diffraction (XRD) and X-Ray fluorescence (XRF) analyses were conducted on the samples. The results showed a standard deviation of less then one per cent, which indicates that the samples were representative and that the method used was therefore adequate. Systematic differences in the phase proportions between normal and fine sinter samples were detected, with the fine sinter containing more haematite than the normal sinter. The sampling method employed gives added confidence that the differences are real.

Jan 1, 2008

The first stage in the refining of lead blast furnace bullion is the removal of copper and is normally done as a batch process in open kettles.A number of attempts have been made to establish continuous processes operating in reverberatory type furnaces, but the growth of accretions in the furnace has always presented a serious problem.The Broken Hill Associated Smelters Pty. Ltd. (RH.A.S.) at Port Pirie have overcome this problem by constructing a reverberatory furnace and ancillary cooling system of a novel design.Although a number of mechanical and metallurgical problems still remain to be solved, it is claimed that a workable continuous copper drossing process has been established.INTRODUCTIONLead bullion emerging from the blast furnaces at Port Pirie is at a temperature of about 1100°C and contains, among other impurities, about 1 per cent of copper.The first stage of refining is the removal of this copper by a drossing operation and in the past this was done, batchwise, by allowing the bullion to cool back in 100 ton kettles.At about 700°C, copper dross begins to separate as a crust on the surface of the kettle and this separation was allowed to continue down to about 450°C when the crust was brokenup and skimmed manually using a long handled, balanced, spoon. The dross was then smelted in a reverberatory furnace to produce a saleable copper matte and separate out lead bullion, which was returned to the drossing kettles. The copper content of the drossed bullion was then further reduced by a sulphur treatment process.The drossing operations involved hard manual labour under arduous conditions and the pouring of hot bullion into...

Jan 1, 1963

By S Meffre, A E. Fallick, K Zaw, I T. Graham, G Giuliani

Dispersed gem corundum is mined from placers, commonly from basalt fields, as occurs along eastern Australian and Asian continental margins. New laser ablation inductively coupled plasma mass spectrometry analysis (LA-ICP-MS) of Australian corundum allows genetic distinctions among these suites and gives clues to their primary lithospheric sources prior to basaltic delivery. Bimodal corundum suites at Barrington Tops, Cudgegong-Gulgong-Macquarie River and Yarrowitch, New South Wales (NSW), include lower Ga, higher Mg æmetamorphicÆ and higher Ga, lower Mg æmagmaticÆ groups. The Barrington Tops æmetamorphicÆ corundum is more Fe-rich (av 4500 - 7100 ppm) than Cudgegong- Macquarie River equivalents (av Fe 1800 - 2100 ppm). Yarrowitch corundum is relatively low in Fe, Ti and Cr. Along with other eastern Australian data (north-east Tasmania; New England, NSW) and from gem fields elsewhere, the combined trace element and O isotope data, reveal considerable geographic and genetic variations within the corundum suites. A few corundum groups contain noticeable Be, Sn, Ta, Nb, a particular genetic message that also precludes easy distinction of treated corundum in the gem trade. Expanding geochemical, inclusion and geochronological data on gem corundum hold promise for characterising derivative gem corundum on both geographic and genetic features.

Jan 1, 2008

By G A. Streltsova

In the paper the main concept of qualitative simulation is determined when computer-aided designing and forecasting of designs of robotised continuous-flow working face complexes for underground mining of hard ores. The parametric model æunderground ore mineÆ and its components û composite models are considered. Frame description of structure of working face complex and methods of organising of rule-oriented representation of knowledge when itÆs operating are given. The architecture of the developed prototype of expert system æworking face complexÆ and construction of a knowledge base for it are described when solving problems of multi-criteria optimisation of computational parameters of the working face complex under conditions of uncertainty. The guidelines for further development of knowledge base and expert system are given.

Jan 1, 2003

By Davies S. G, Jayaweera A

The oxidation of nickel sulphide and copper sulphide concentrates, and coal, has been studied under non-ignition and ignition conditions using Differential Thermal Analysis (DTA) and Thermogravimetry (TG). The non-ignition reaction was favoured by slow heating rates < 10°C min-1), low masses < 10 mg) and an air atmosphere. Under these conditions, the typical stepwise oxidations of the various sulphide minerals present in the concentrate were observed as resolved exothermic peaks in the DTA curves and weight losses in the TG curves. Above a heating rate of 10°C min-1 , sample masses in excess of 10 mg and an oxygen atmosphere, an ignition reaction was induced, as indicated by a major high energy exotherm in the DTA curve and a major rapid weight loss in the TG curve. The ignition temperatures of the minerals under ignition conditions, found for 15 mg samples heated at 20°C min-1, were 434°C for the nickel sulphide concentrate, 372°C for the copper sulphide concentrate, and 230°C for the coal. By plotting a curve for mass against ignition temperature at constant heating rate and extrapolationto zero mass, a value of 470°C was obtained for the mass independent ignition temperature of the nickel sulphide concentrate. Ignition temperatures and extents of reaction at various temperatures were obtained using the TG technique in a novel manner which produced heating rates of 4500°C min-1. Under ignition conditions, the oxidations approximate to flash smelting conditions.

Jan 1, 1985

In the last 100 years, statistical sampling theory for particulate materials has developed to a stage where sampling systems can be confidently designed to provide assay results of known and controlled variance for a chosen time period. The two independent sources of sampling variance, namely intrinsic and distributional heterogeneity are defined and explained quantitatively. Intrinsic heterogeneity is characterised by the sampling constant for the material and distributional heterogeneity is quantified by the process steam variogram or covariance function. The means by which sampling systems can be designed to an accuracy specification is described.

Jan 1, 2002

By El-Ansary M

Estimation of in-situ resources and recoverable ore reserves for the Boddington Gold Mine feasibility study was done by applying an essentially "classical" ore reserve method. This relied completely on customized graphics-based computer software requiring close co-operation and interaction between geologists and mining engineers. All geological and mining outlines were interpreted and digitized manually. Classification of selectively mineable reserves into ore, marginal and waste categories was done using a method involving convolution, devised by Dr S Carras of the Systems Research Institute of Australia, and Mr R Hooper of Kinhill Stearns. The estimation process was complicated by the frequently conflicting requirements of the various joint venture partners. The resulting ore reserve figures therefore satisfied only the most general expectations of each partner.

Jan 1, 1987