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By Gordon Revey

The challenge of managing blasting risk, types of risk, public perception, and a system for managing risk were covered in the first part of this article in the May/June 2000 issue of the Journal of Explosives Engineering. This final part of this two-part series provides a method for identifying specific blasting risks and reviews the importance of community relations.

Jan 1, 2001

By A Liu, T Ren

Gas explosion in underground coal workings can pose a serious threat to the safety of mine workers and the entire mine operations. Gas explosion is a very complex thermal-chain reaction in a confined underground environment. Based on combustion and explosion theory, three dimensional (3D) computational models were developed to simulate mine gas explosion flame and overpressure wave propagation in a single entry gateroad in underground coalmines. Six different explosion scenarios were modelled and compared with large scale experimental results and AutoReaGas simulations. Model validations show that the use of shear-stress transport (SST) k-? model together with eddy-dissipation model (EDM) produces good agreement with both experimental and AutoReagas simulation results. Modelling results demonstrated that the changes of temperature versus time can be divided into four stages, ie the initial condition stage, and periods of warm-up, active burning, and burnt-out. Assuming a limited volume of methane is involved in the explosion, the maximum temperature decreases as the distance increases from the explosion point, with the highest temperature reaching about 2460 K. Modelling results show that the evolution of the explosion flame shape experiences four typical stages, ie spherical flame, finger-shape flame, flame with the skirt touching the side walls (ribs) and tulip flame, which are similar to the pattern of a duct explosion. The pressure in the gateroad remains the same as the initial value before the arrival of the explosion wave and then increases rapidly to the maximum value. Modelling results from this study will be used for the design of explosion arresting devices and mine seals in underground coalmines.CITATION:Liu, A and Ren, T, 2017. Computational simulation of gas explosion and its propagation in single entry gateroad, in Proceedings Australian Mine Vent Conference 2017, pp 181–188 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By L. du Plessis

The name FISH (Fully Integrated Sort House) refers to a class of technology deployed at Jwaneng Mine final diamond recovery. The FISH concept is based on three pillars, namely: ?Improved sorting efficiency FISH is based on laser technology, which is more efficient than hand sorting for certain product categories. Laser sorting is based on measuring in-elastically scattered light from molecules and this is referred to as Raman spectroscopy. The Raman scattered light occurs at wavelengths that are shifted from the incident light by the energies of molecular vibrations ?Availability of production information Roller gap diamond size distribution information is generated on line for upstream process optimization ?Improved product security A ?hands-off? philosophy reduces security risk during operation and maintenance of the plant. In addition, a number of lessons were learnt about the application of new technologies in the industry: ?The required human competency profile demanded by new technology should match the available competencies of the operational staff ?An integrated information management system should be fully functional for both production management and diamond control purposes ?Operational feedback must be correctly evaluated to identify design, maintenance, training and operational issues so as to accelerate the maturity of the new technology within the time span of the sustainable operations project ?Project execution and technology maturity risks have to be evaluated and married to ensure risk mitigation by means of suitable project resource and contracting model selection.

Jan 1, 2003

By James J. Gusek

Passive-treatment systems that mitigate acid-rock drainage (ARD) from coal mines have operating since the mid-1980s. Large systems at metal mines are being contemplated. A 95L/sec (1500-gpm) capacity system is planned this year at an underground lead mine in Missouri. Mine, process and environmental managers need to understand how and why passive-treatment systems work. They must understand what operational limitations to expect, as well as the economics of construction and operation compared to the alternatives, like lime precipitation. Wetlands have been recognized as nature's method of improving water quality. Contaminant reductions can occur through the precipitation of metal hydroxides, sulfides and carbonates and pH adjustments. Local conditions, oxidation state and water and soil chemistries dictate whether these natural reactions will occur under oxidizing (aerobic) or reducing (anaerobic) conditions.

Jan 1, 1995

A South African gold mining rock-related fatal accident database has been analysed in order to determine rock-related fatality trends in the gold mining industry over the period 1990 to 1998. This analysis was extended further to include some of the individual reefs mined and focused particularly on the Carbon Leader Reef, the Ventersdorp Contact Reef, the Vaal Reef and the Basal Reef. Rock-related accident locations are also presented. A stope rock-related risk is proposed, where the fatality rate in terms of rock-related fatalities per million square metres mined for the gold mining industry as a whole is compared to individual reefs, allowing a stope rock-related risk to be attributed to the individual reef. This comparison is extended further by removing the contribution by the reef being evaluated from the industry data, thereby allowing this reef to be directly compared to the rest of the industry with respect to a stope rock-related risk.

Jan 1, 2001

By T. R. Ellis

Minerals Appraisers/Valuers often find great difficulty or failure in attempting to employ the Sales Comparison Approach to the Market Value Appraisal of development and operating stage mineral properties. An important factor generally overlooked is a comparison of net operating income (NOI) margins on a per-unit-of-production basis between mineral properties, whether these be demonstrated or forecast margins. NOI margins can vary greatly between mines or quarries that are producing similar products. Ultimately, the expected NOI margin determines what a buyer is willing to pay for an income producing property. Common criticisms of the sales comparison approach by minerals appraisers are introduced. These are counterbalanced by raising some issues in the way the inputs for the Income Approach are usually derived by minerals appraisers, and by review of some conspicuous examples of the much too common misuse or abuse of the income approach in market value minerals appraisals. Example transaction analyses and sales comparison analyses are used to demonstrate the author?s methodology for adjusting units of resource in his transaction adjustment tables (see APPENDIX). The examples are used as the basis for discussion of ways to employ adjustments for operating economics and many other factors, while cautioning about the potential for double counting. The conclusions include a recommendation that minerals appraisers attempt to apply at least two of the three valuation approaches when appraising the market or fair value of development and operating stage mineral properties, the two being the sales comparison and income approaches.

Jan 1, 2011

By C Johnstone

Project management is not a task to be undertaken lightly. Mining projects generally present even more challenges due to ChinaÆs remoteness and complexity. Having experiences in project management in the West is certainly an asset, but China can present the uninitiated with any number of headaches. To undertake a project there can have many problems that are unique to China. For the last 15 years, China has seen an increasing number of foreign capital investment projects in the mining industry. Practices involved in mining project development have experienced/are experiencing an evolution. Since 1996, Sino Gold Mining Ltd has delivered three mines in China, ie Jianchaling Gold Mine, Jinfeng Gold Mine and White Mountain Gold Mine. Through the work, Sino Gold has established a solid knowledge base and a capable and skilful workforce in effectively undertaking mining projects in China. This paper is concerned with the experiences accumulated so far by Sino Gold in project management in China. An overall review is conducted regarding the reform of the mining project development in China. Opportunities and challenges are highlighted within the political, economic and culture context. Brief summaries of the development of the three gold mines are presented.

Jan 1, 2009

By T C. Ooi, L Lu

Owing to ongoing development of new orebodies and changes to existing mining operations, new ore types with distinct mineralogy, porosity and textures are generated as feed for iron and steelmaking. Moreover, further product differentiation occurs as fine ores are increasingly beneficiated to achieve grade. A study was necessary to characterise a suite of iron ore fines in terms of their propensity for formation of quasi-particles and green bed permeability prior to sintering. In this study, two Marra Mamba bedded iron deposit (BID) samples, one Pisolitic channel iron deposit (CID) samples, two dense hematite samples (coarse and fine grained microplaty hematite), one hematite-goethite BID samples and one hematite-goethite bedded/detrital iron deposit (BID-DID) composite sample were investigated. Both Marra Mamba fines and Pisolitic fines exhibit the highest green bed permeability followed closely by hematite-goethite fines, fine microplaty hematite fines, hematite-goethite BID-DID composite fines and coarse microplaty hematite fines at a moderate sintering bed depth of 500 mm. While porous fines generally form better quasi-particles upon granulation than dense fines, the amount of moisture addition increased due to the moisture saturation of the porous fines. As sinter strands become ever larger and deeper, it was necessary to examine the granulation performance of these ore types at a range of bed depths ranging from 300 to 900 mm. On average, the green bed permeability achieved by different ore types, decreased by approximately 7.5 - 9 Japanese Permeability Unit (JPU) as the bed height was increased from 500 mm to 900 mm. In order mitigate the effect of lower bed permeability of the deeper beds, small additions of hydrated lime were investigated as a binding agent to facilitate the formation of strong micro-pellets. With the addition of three per cent hydrated lime, equivalent to approximately 2.3 per cent burnt lime, the majority of fines achieved adequate permeability for deeper bed sintering, with the exception of coarse microplaty hematite fines. In simulated coastal steelmaking sinter blends, it was found that the overall granulation performance of the blend is contributed to by individual fines constituting the blend. Therefore fines possessing favourable granulating properties impart better granulation to the blend as a whole.CITATION:Ooi, T C and Lu, L, 2013. Effects of ore type and binder addition on the formation of quasi-particles and green bed permeability at different sintering bed depths, in Proceedings Iron Ore 2013 , pp 459-466 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By L. Lehasa

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

Jan 1, 2012

By J. R. Piper

“Old Borate,” located in the Calico Mountains east of Barstow, California, lead domestic colemanite production from 1884 through 1907. Mineral exploration at “Old Borate” in the early 1980's, examined borate mineralization in Tertiary lacustrine strata. Surface sample and drill hole locations, geology and structure, were hand-drafted on paper maps. To re-evaluate this data, the information was digitized using Geographic Information Systems software. Digital Elevation Model based terrain modeling integrated surficial samples with drill hole data to locate favorable drilling targets. Structural relationships were used to identify hypothetical resources formed by the leaching of boron from surface exposures, redeposited at depth.

Jan 1, 2001

By M. Schafer

The 6-m- (20-ft-) diameter cast-in-place tunnel lining for Phase 3 of the Mill Creek Tunnel (MCT3) has been completed. This article summarizes aspects of liner design and ad-dresses the construction approach in placing the liner in areas of tunnel that experienced crown overbreak. Tunnel lining production rates, installation procedures and form buoyancies experienced during concrete placement will also be presented. The Mill Creek Phase 3 tunnel (MCT-3) is expected to be completed this year. It is one of the largest tunneling projects undertaken by the Northeast Ohio Regional Sewer District (NEORSD) to date. The tunnel horizon is situated within the Devonian Chagrin Shale rock formation at an average depth of 85 m (280 ft). The tunnel was excavated using a two-pass method. A full face, fully shielded, Robbins 7.2-m- (23.8-ft-) diameter tunnel boring machine (TBM) was used to excavate approximately 4,500 m (15,000 ft) of tunnel and facilitate installation of initial supports (first pass). The final lining (second pass) consists of 305-mm- (12-in.-) thick cast-in-place reinforced concrete and integral low flow channel. Seven shafts were constructed on the project. The excavation of the tunnel commenced at Shaft 14 and proceeded down grade to Shaft 9, the terminus shaft. Because of the presence of overbreak in the tunnel crown, measures were required to support the form and counteract the effects of buoyancy during concrete placement.

Jan 1, 2008

By F. B. Samani, B. Stabel

The 1,000 MW Hydro Power Station Masjed-e-Soleiman (formerly called Godar-e-Landar) in Iran is under construction since 1992. The rock engineering aspects of the major underground structure, i.e. the powerhouse cavern shall be reported on in detail. The geotechnical investigations are described and results given. The results of several geotechnical analyses are presented. The designed and executed rock support is given. A description of the monitoring systems and typical measurement results obtained during and after excavation are presented. The lessons learnt during construction of the Stage-I powerhouse cavern were applied on the extension of the powerhouse cavern, which is to house an additional 1000 MW. Details regarding the unexpected behaviour of the Mudstones are given. Die 1000 MW Wasserkraftanlage Masjed-e-Soleiman (vormals Godar-e-Landar genannt) befindet sich seit 1992 in Bau. Dieser Artikel berichtet im Detail über die felsbaulichen Aspekte der Untertagebauwerke, insb. der Maschinenkaverne. Die geotechnischen Untersuchungen werden beschrieben und deren Ergebnisse wie die Ergebnisse verschiedener Berechnungen werden präsentiert. Die geplante und die ausgeführte Felssicherung wird angegeben. Die eingebauten Überwachungseinrichtungen werden beschrieben und typische Ergebnisse während des Aushubs und danach werden dargestellt. Die Erfahrungen beim Aushub der Kaverne der Stufe I wurden beim Entwurf der Kaverne der Erweiterungsstufe II, die weitere 1000 MW beherbergen wird, berücksichtigt. Details zum unerwarteten Verhalten des Schluff-/Tonsteins werden angegeben. La centrale hydroélectrique de Masjed-e-Soleiman (dénommée anciennement Godar-e-Landar), d’une puissance de 1.000 MW, est en construction depuis 1992. Un rapport détaillé sera présenté sur les aspects relatifs à la construction en enrochements de l’aménagement souterrain principal, à savoir la caverne abritant la salle des machines. Une description des investigations géotechniques réalisées y est fournie ainsi que les résultats correspondants. En outre sont présentés les résultats de plusieurs analyses géotechniques. L’ancrage dans la roche tel que projeté et réalisé est présenté. Une description des systèmes de contrôle ainsi que les résultats de mesures typiques obtenus au cours des travaux d’excavation sont donnés. Les leçons tirées lors de la construction de la Phase 1 de la caverne de la salle des machines furent appliquées à l’extension de la caverne de la salle des machines, qui doit abriter une unité supplémentaire d’une puissance de 1.000 MW. Par ailleurs, des détails sont donnés sur le comportement inattendu des argilites.

Jan 1, 2003

By Raymond W. Henn, Kent A. Pease, Glen J. Rorison

The paper focuses on construction of a 2.55-km (8,365-ft) long, 2.4-m (8-ft)diameter storm drain tunnel in Evansville, Indiana. The tunnel was driven through saturated soft ground varying from clay to fine sand. The paper presents: an overview of design and design rational including specific EPB machine requirements; the contractor’s proposed and accepted alternative construction methods and TBM design; and construction issues and performance. Some of the key points discussed are the use of the TBM in different operational modes for alternative ground conditions, the effectiveness of dewatering systems, production rates, and issues such as surface settlements and gas.

Jan 1, 2001

By Steve Kral

Worker safety is an issue that transcends industries, whether it be mining, construction, manufacturing or even general office work. In the mining industry, safety and training are particularly important because mining is a dangerous occupation. Throughout the years, federal and state safety regulations have been written and revised to keep up with the changing technologies. And mine operators have installed their own safety and training programs. They have come to realize that a safe and healthy workforce has positive effects on productivity and profitability —not to mention avoiding the high costs of injury-related absenteeism.

Jan 1, 2003

By L. P. Weber

During the years 1983-1987, a research programme, jointly performed by the steel producers ARBED, British Steel Corporation, Peine-Salzgitter, Unimetal, and co-sponsored by the European Community for Steel and Coal (ECSC), has been carried out on steel H-piles of different shapes. The initial aim of the testing programme has been the improvement of bearing capacity, both in sandy and clayey soils. At two test sites, standard H-beams are compared to H-piles with different types of laggings or to H-piles grouted both under low and high pressure. In this paper and in view of the open european market in 1992, the H-pile capacities and their corresponding allowable loads, determined from codes, recommendations and computation procedures in use in Belgium/Luxembourg (B/L), France (F), Federal Republic of Germany (G), and the United Kingdom (UK) as well as their evaluation from dynamic CAPWAP and Case methods are compared to the static capacities measured in-situ. In addition, procedures for estimating the load/movement behaviour of H-piles from CPT, pressuremeter, and CAPWAP are compared to the measured curves.

Jan 1, 1991

By Nicholas Adrian Barcza

"What affects and influences one’s perspective of the mining and metallurgical industries?One’s perspective of the industry we work in changes over time as a function of our experience as well as from the interaction we have with colleagues locally and probably even more so with those internationally. Furthermore, the ever-changing environment continues to impact the context in which one sees things. Living mostly in South Africa through its changes in the past fi fty years but also having the opportunity to travel extensively and work on projects abroad adds an invaluable richness to this more global perspective. One of the greatest challenges is how best to use this experience to endeavour to support the many potential opportunities in southern as well as sub-Saharan Africa. However, one has also to face the realities of how the best interests of the country and its peoples are sadly often not well served for various unfortunate reasons. Investment, education, regional stability, and good governance are some of the most critical considerations for the prosperity and survival of the region.The mining and metallurgical industry in southern and sub-Saharan Africa changed significantly during the post-colonial and apartheid eras as a result of global and regional developments that have impacted the ownership of businesses, the technologies used, and products produced in a manner that was not envisaged even fi fty years ago. Southern Africa’s mining and metallurgical industry has progressed from one based mostly on diamonds and gold in the late 19th century to a much more diverse one that involves the production of a variety of other precious, base, and ferrous metals and minerals as well as coal and industrial minerals. The infrastructure and manufacturing capacity was largely developed to meet the needs of this industry during its growth phases, but even though the dynamics have changed there is still a need for more efficient and effective support systems in the region."

Jul 1, 2019

By Daniel H. Israel

Indian tribes own a substantial portion of the West's minerals. More importantly, Indian reservations contain coal, oil and gas, uranium, and oil shale reserves in unusually large and unencumbered blocks. Many tribes are now prepared to intensify development of their large reserves knowing that they can offer energy partners the unique opportunity to develop major energy facilities free of overlapping local, state, and federal permitting authorities. The tribes, therefore, can offer mineral developers both substantial reserves and an unusual degree of freedom from a multiplicity of government regulation. In the past, Indians and energy companies enjoyed only partial success as business partners. Indian tribes lacked the resources and know-how to act as equal partners with large oil and gas and mining operators. The tribes relied on the Bureau of Indian Affairs (BIA) to initiate and execute reservation energy projects, and as a result the tribes never developed adequate tribal structures and the expertise to responsibly manage their energy resources. At the same time industry made little effort to understand and learn the laws, customs, and institutions existing on Indian reservations. To the contrary, industry found it easier to bypass the tribes and deal with BIA officials. But the situation has changed. In 1975 the tribes organized an effective coalition, the Council of Energy Resources Tribes (CERT), which recently acquired substantial federal assistance to bring the tribes a level of technical and business expertise that begins to equal that of industry. Because the tribes have changed the rules of the game, industry must now change and learn to work directly with tribal governments. A working knowledge of Indian law, practices, customs, and policies must be acquired by energy companies before beginning negotiations with tribal governments for development of reservation energy resources.

Jan 6, 1980

The compilation of the sampling nomogram is an essential tool in the optimization of a sampling protocol and allows the operator to track the change in relative variance of the sampling error (the Fundamental sampling error) during steps of comminution and mass reduction in the process of recovery of the aliquot for analysis. The data required for the compilation of the nomogram are centred on the sampling constant K and the exponent, alpha (a) of the nominal fragment size. Five methods for establishing K have been identified, but two of them, the duplicate sampling analysis method and the heterogeneity test method purport to provide such constant. The step by step procedure for each of these two methods was examined using broken ores from three mines, Mponeng mine, Kloof mine, and Lily mine. Two of these mines (Mponeng and Kloof) are typical Witwatersrand-type gold mines, and the third is an Archaean-type shear related gold deposit situated in the Barberton Greenstone belt. The results suggest that the factor K derived using the heterogeneity test is very accurate, but applies only to a single size fraction in the spectrum of comminuted materials. The calculation of gold grain sizes using this method appear to be too small and do not conform with the results from detailed mineralogical studies. The factors K and alpha derived using the duplicate series analysis are appropriate for use across a wide spectrum of comminution sizes and also provide realistic gold grain sizes, comparable with the equivalent circular diameter of gold grains identified in mineralogical studies of the ores.

Jan 1, 2010

By John Heter

An alum/sulfur deposit (USDA organic registered) was mined underground for alunite (K,Na) Al3 (SO4)2 (OH)6 from the early 1900s to the 1930s. It is now being mined as an open pit quarry. A larger assemblage of minerals is included with this method (Alunite, Potassium?Alum, Jarosite, Gypsum, Native Sulfur and K-feldspar). This assemblage of minerals provides the necessary requirements as a Volcanic Soil Conditioner Sulfur-Potash. Heart of Nature? Company has been marketing this product to farmers on the west coast as a (1) pH reducer, (2) soluble sulfur and potassium source for plant growth and (3) soluble calcium. Recently, a new market has been tapped. This product has been found to solve many odor, bacteria and algae problems faced in the dairy industry.

Jan 1, 2008

By R. Schulz, K. King

Concentrating Line 6 just went down again. The control room operator checks the graphic display. Only one piece of equipment shows an alarm. Clicking on the ball mill icon, he discovers the culprit was the low flow lube switch. The flow looks okay now, but it is the third time this week the switch has stopped the line. Maintenance is called, the switch replaced and the line is up running again. Sending the right person to the right spot immediately can save hundreds of hours of downtime every year. This paper discusses the principles behind implementing smart First-Out Fault Detection to dramatically reduce equipment downtime in new, or existing control system architectures. Methodologies are presented to maximize the system benefits, while minimizing development costs. Case histories are presented for a number of successful implementations in mineral processing plants.

Jan 1, 2001