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A mining companyÆs approach to managing the risk of theft of explosives and initiating devices should be underpinned by an organisation-wide policy developed with internal and external consultation. It should be based on the principles of sound proactive risk management, planning, monitoring and remedial action. This paper aims to provide mining (and construction)organisations with the rationale and many of the tools they need to control explosive security risks. As with all legislative compliance, they are best managed by incorporating the statutory and legal requirements into company policies, management systems and plans, operating procedures and culture. This is the approach that has been adopted in this paper. Trends we should expect: more prescriptive legislation and stricter government regulations; enhanced enforcement and more prosecution; more sophisticated detection systems, eg airports; additional compliance costs; additional vigilance on record keeping; improved risk awareness and risk communication; wider use of explosives policies, management systems and plans; and additional security staff with investigative skills.It should be noted that mining companies will be required to play their part in reducing the likelihood of explosives, intended for mining purposes, being wrongfully used to threaten, hold to ransom or to injure individuals or members of the public or to produce property damage. This will be done by putting in place safeguards to reduce the risk of theft of explosives while they are under their control. On that basis, this is a business risk assessment rather than a hazard risk assessment. A conclusion of this paper is that mining companies can and should play their part in reducing the supply of explosive materials that can then be used for illegal activities. In fact, mining companies have always had this duty, but now the stakes are higher û æcomplacency no longerÆ.

Jan 1, 2004

Nippon Telegraph and Telephone Corporation (NTT) developed a new construction method (the M-2 method) that could drive a long, curved small-diameter tunnel (4>1.2 m) without human labor. This method employs the cast-in-place lining system, using quick-hardening resin mortar, so that it can greatly increase the driving distance and execute both long distance driving (longer than 500 m) and curved driving with a radius of curvature of 200 m. Furthermore, the central control system with a mini-computer in a vertical shaft enables all work in a small-diameter tunnel, i.e., excavation, lining, and transportation of excavated soil and materials, without human labor. NTT conducted several field tests and a Practical Application Test (P.A.T.) under a public road bearing great traffic. Good results were obtained and the practicability of this method was demonstrated. Therefore, from now on, NTT will apply this ii-2 method to drive telecommunication cable tunnels in urban areas. This method will also be applicable to constructing public tunnel facilities, such as for water, sewage, electricity and gas.

Jan 1, 1987

Deposition of uranium in the South Alligator river area has been influenced structurally by reverse faulting; and lithologically by carbonaceous shales and sandstones. Mineral assemblages suggest a mesothermal-epithermal epigenetic mode of origin. The ultimate source of the uranium and associated metals is probably in deep seated magmatism which is expressed at surface in the widespread penecontemporaneous vulcanity.

Jan 1, 1968

By Yesil MM, Bozdag T

The swelling process is an impor- tant problem causing damages to the structures in or on swelling rocks, both during construction and operating life. To understand swelling problem, a number of testing methods have been developed by many researchers. In these studies, the swelling parameters, in most cases, are derived from oedometer tests. The swelling parameters determined from oedometer type tests represent one-dimensional behaviour (one-dimensional swelling law) therefore, it is quite difficult to extrapolate the oedometer type test results to the three-dimensional in-situ conditions. To overcome these problems, a three-dimensional approach is suggested for clay bearing rocks. Results of triaxial swelling tests conducted on marl from Dodurga Lignite Coal Mine are presented. Triaxial swelling characteristics of the marl are presented and design approach for tunnels is described.

Jan 1, 1992

By J Zhou, X Bi, Y Yan, W Peng, H Yang, D Weng, P Li

Fortescue Metals Group (FMG) fines from Western Australia is a hematite and limonite mix characterised by high crystal water content. Due to its higher supply capacity and lower prices, the Wuhan Iron and Steel Corporation (Group) intended to use more FMG fines in the sinter mix. It is understood that sinter quality is closely related to its microstructure featured by the hardness and brittleness of different mineral phases, the content of micro pores, and trans-cracks. In order to maintain sinter qualities such as tumble index, reducibility and so on at higher FMG fines blend ratios, a research project was initiated to study the effects of the FMG fines blending ratio on sinter microstructure. Research results showed that at higher FMG fines ratios, the hardness of hematite and magnetite were both decreased while the hardness of calcium ferrite showed a tendency to decrease. The number of cracks that were generated during Vickers hardness measurement in various mineral phases decreased, but their length was shortened, and the variation of crack lengths increased. The contents of hematite and magnetite were also reduced and the reduction of magnetite was clearer. Also the content of calcium ferrite and pores rose and the magnitude of the increase of pores was greater. Among all the mineral phases in sinter cakes, the Vickers hardness of hematite was highest within the range of 879 N/mm2 ~ 942 N/mm2, and therefore the decrease of its content in sinter and the enhancement of its brittleness, ie the number of cracks increased, were harmful to sinter strength. In addition, the excessive increase in pores content is also not favourable to sinter strength.CITATION:Bi, X, Yan, Y, Zhou, J, Peng, W, Li, P, Yang, H and Weng, D, 2013. Study of sinter microstructure with various blend ratios of Fortescue Metals Group fines, in Proceedings Iron Ore 2013 , pp 331-336 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By D H. Bell

Slab-buckle failures in coal sequences involve thin slab deformation in strata dipping parallel to the footwall, and are a consequence of both unloading and the weak nature of the thinly bedded rock mass. Methods of modelling and predicting such occurrences include: +        a conceptual model using a base friction table, +        a mathematical model using the Euler solution for column and beam bending (after Goodman, 1980), and +        computer analysis techniques such as UDEC (Universal Distinct Element Code after Cundall and Hart, 1993).   Slab-buckle failures have the potential to seriously disrupt production because of their volume and rapidity, and to endanger both equipment and personnel working on the pit floor.   In July 2004 a large slab-buckle failure occurred overnight after a new batter and bench had been formed at the Malvern Hills Opencast Mine in inland Canterbury. This involved the entire length of the pit (85m along strike) when a 2m thick intact slab with a total volume of ~3500m3 translated down dip 6.2m on the base of a thin coal seam to form a pronounced buckle at the toe. The coal measures consist of finely laminated mudrocks with multiple coal seams of varying thickness dipping ~45¦ to the southeast, and the opencast mine had been designed with footwall batters formed parallel to bedding with a vertical bench separation of 15m.   Back analysis of the Malvern Hills failure was necessary to investigate the controls on footwall instability, and for future mine design. An engineering geological model was created and samples of the slab material and failure surface were collected and tested to establish the required parameters for use in the Euler solution for column and beam bending. Back analysis using the Euler solution provided unrealistic results that overestimated the overall length of a stable slope by more than 10 times.   No further large scale slab-buckle failures have developed at the mine site, in part because of the slow rate of coal extraction, but precautionary drainage of the footwall slopes has been undertaken to improve overall batter stability. The location of the slab-buckle failure on a critically positioned pre-sheared thin coal seam with full hydrostatic head is considered the most probable cause of the July 2004 failure, rather than inherent instability of the generic bench and batter arrangement adopted. The use of a precedent-based engineering geology approach to future mine design is considered the most appropriate solution in the circumstances.

Jan 1, 2007

The appearance of the Cornish miner in South Australia was, in the simplest terms, the result of resource development economics. In Cornwall in the middle of the 19th century tin and copper mining was declining, while in the new colony of South Australia copper mining was booming. Experienced hard rock miners in Cornwall there- fore escaped unemployment at home by accepting an assisted passage to South Australia. There, in a colony where they were needed, they made their skills available and received good wages. There are many testimonies which support this simple thesis. Take for example the following extracts from contemporary newspapers in Corn- wall: Persons of small capital will find this an excellent opportunity for emigrating to the young and thriving colony ... The miner will find a rich and unbroken field for his operations. The Colony abounds with minerals... (West Briton, 19 July 1844) Miners make a great deal of money here (South Australia). All of them earn ú2 to ú3 per week and in many cases when they have a portion of the mine on tribute one person has cleared ú100 in a couple of months or so. (Cornwall Royal Gazette, 21 July 1848)

Jan 1, 1987

By Fuller P. G, Miller D. R

Hydraulic fill using surface sand deposits or cycloned tailings has been used in underground mining for at least fifty years. Current technology requires a permeable fill and high cement additions for strong fill. Shortages in quantities of acceptable fill with finely ground ore may require rockfill or aggregate to be introduced as a supplement and these usually incur additional distribution costs. Alternative approaches to the problem are now being developed whereby the pulp density of the fill is raised so that it is delivered either as a dense slurry or as a paste. These regimes of fill behaviour are defined together with the plant and pumping techniques required to prepare and deliver the materials. Test techniques to define the different regimes of behaviour are identified and the variation in material properties for fills with varying pulp densities are outlined. The results indicate that high pulp density fills are stronger and have less permeability restrictions than conventional fills and that aggregate can be carried with the pulp. Thus the disadvantage of finer materials can be turned into an economic advantage. Criteria are developed for defining the type of operation suited to this Technology.

Jan 1, 1986

By H F. Galbiatti, G J. I dos Santos, A de C Zapparoli

The Grao Para and Rio Maria greenstone banded iron formations (BIFs), within the Carajas mineral province, exhibit distinct lithological and petrographic fabrics, together with pronounced differences in their surface expression, real thickness, iron grade and tonnage. These geological differences support a new model for the regional distribution of iron formations in the Carajas Mineral Province.

Jan 1, 2009

By K M. P Singh, K M. K Sinha, G S. Jha, T Gouricharan, K K. Sharma

The majority of the powerplants in India are fed with non-coking coals, with the coals dispatched from their respective mines via wagons loaded by a rapid loading system or pay loader. The usual top size of coal is 200 mm and sampling is carried out manually from wagons. The manual method of wagon top sampling of large size raw coal is not only difficult, but also violates some of the fundamental principles of sampling. As per sampling requirements, samples are to be drawn from the full depth of the wagons, which is impossible to be done manually. Since the ash distribution in the different size fractions is not homogeneous, the results from the samples, which do not reflect the true size distribution of the lot, are likely to be biased. More importantly, sample collection by shovel from the top is a function of human discretion and not governed by the equiprobability rule. In another case, the sample has been collected by a cross belt-type auto mechanical sampler for 200 mm size coal at one of the super thermal power stations. Test analysis shows that coal collected using a cross belt-type mechanical sampler also has significant deviations from stopped belt coal samples of 200 mm size due to size segregation. Studies carried out on wagon top sampling through specially designed experiments reveal some interesting features. The presence of bias in wagon top sampling is apparent when compared with the ‘stopped belt’ sample. In this paper, a comparative study between manual wagon top sampling/auto mechanical sampling with respect to stopped belt sampling has been conducted for coal of size 200 mm. In addition, precision studies have been performed for wagon top sampling/mechanical sampling for Indian thermal powerplants.CITATION:Sinha, K M K, Sharma, K K, Jha, G S, Singh, K M P and Gouricharan, T, 2014. A comparative study of manual wagon top sampling and auto mechanical sampling of 200 mm size coal with respect to stopped belt sampling of thermal coal at Indian super thermal powerplants, in Proceedings Sampling 2014 , pp 43–48 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 29, 2014

The operation of cyclones and cylinders is briefly described and com- pared, and a number of recent applications in mineral, gold and coal plants discussed. The capacity of an existing pump and cyclone in a circuit can be sig- nificantly increased by retrofitting a cylinder in series to predensify the cyclone feed. The cyclone overflow product size can also be adjusted and controlled using a variable aperture valve between the cylinder and the cyclone. This predensifier-cyclone system has been used at plant scale to con- trol the pulp density of the feed to cyanidation in gold plants, to size flotation feeds before split conditioning and to deslime and classify in gravity plants. Application in a typical regrind circuit is considered. Cylinders and cyclones also have numerous applications in water management systems, e.g., degritting mine and plant waters to protect pumps, sprays and other equipment. Screen undersize and flotation con- centrate dewatering circuits are described to illustrate how suitable stream recycles can reduce water consumption, optimize fresh water use and improve efficiency.

Jan 1, 1988

A Feasibility Study to determine the future of ZC Mines was completed in mid 1987. Early in this study, which lasted two years, it was identified that significant reductions in treatment costs would result if the Zinc Corporation Concentrator was closed. All of the production from the existing two mines, The Zinc Corporation Limited (ZC) and New Broken Hill Consolidated Limited (NBHC), would then be treated in the concentrator at NBHC.After a partial upgrade of the NBHC concentrator, the ZC concentrator was finally closed and all of the equipment disposed of. This closure highlighted the need to concentrate all ore haulage in one shaft to further reduce operating costs and remove the cost of surface transport of ZC production to the improved NBHC concentrator. This paper outlines the changes that were made to improve the haulage system for ZC Mines. After a number of options were investigated, it was finally decided that the upgrade of the existing NBHC haulage shaft was the best option even though some production would be lost while the upgrade was in progress.

Jan 1, 1988

By A J. MacDonald, M P. Raffield

The South Deep massive orebody consists of 20 to 30 m of payable conglomerates ranging in dip from 11¦ to 20¦ and at depths of between 2400 m and 3400 m. The mine design process selected a mining method with a proven record of application that could be adapted to overcome the inherent difficulties associated with the depth, thickness and structural influences of the South Deep orebody. A modified cut and fill mining method provides a concentrated and highly flexible method of extraction. An integrated destressing cut will enable the modification of the stress environment such that it is suitable for massive mining operations. The choice of backfill type and stoping width in the destressing cut ultimately determines the characteristics of the stress modification and, as such, is critical to the success of the cut and fill operation. This paper discusses the decision process undertaken to determine the optimum backfill type and stoping width combination in terms of, conditions in the destressing cut faces and in the massive mining environment. Numerical modelling has been extensively used to analyse various scenarios to aid in the decision process.

Jan 1, 1998

By S Jahn, M Noel, E M. Rykaart, M Pau

Three soil cover test areas were constructed on waste rock backfilled into the Lichtenberg Pit, near Ronneburg Germany. A fourth, uncovered area was included as a control. Each test area measures 50 m by 65 m, and was constructed using full-scale equipment and construction practices. Extensive material sampling and testing was included as part of the construction. Devices were installed in each plot to monitor meteorology, infiltration, run-off, interflow, soil moisture, soil temperature, and soil pore gases. Boreholes were completed in each area and instrumented for temperature, pressure and pore gas sampling to a depth of approximately 60 m. Data from the monitoring instruments have been collected since July 2000, and have been comprehensively analysed and modelled on two occasions. The paper presents an overview of the test area design and instrumentation and the results of the two comprehensive data reviews. The reliability of the various monitoring methods is discussed and experience with several innovative methods is reviewed. The difficulties encountered in modelling the data set using common soil physical models are discussed.

Jan 1, 2003

By S Wasi, J Tobiczyk, J Roszkowski

Methane and fire hazards have a vital effect on work safety and continuity of mining plant operation. In the 1990s, the SMP hazards monitoring and ventilation control systems, based on continuous measurement of air parameters, were put into operation at nearly 30 Polish mines. These systems provide continuous measurement of methane concentration within the range of zero to 100 per cent with automatic switching off of electrical energy immediately after detection of potentially explosive conditions. Early detection of coal spontaneous combustion and open fires is made by continuous measurements of CO, CO2, smoke and O2 content in mine air as well as temperature changes in air and rock mass. The essence of the system is intrinsic safety of all underground instrumentation and uninterrupted central power supply from the surface. All abnormal and critical states are signalled to the mine control room. These trigger alarm and emergency procedures. The computer based ventilation monitoring and control system also performs the function of an expert system for fire detection and underground fire fighting. The mine control operator (dispatcher) makes use of stored data in computer escape route schemes and procedures for the safe withdrawal of miners from hazardous areas. The operator can put in motion intrinsically safe alarm signalling units and banners with programmed messages indicating escape routes.

Jan 1, 2005

By Stanojevic R, McGlinn PJ, Day RA, Levins DM

This paper reports the results of a number of studies that Ansto has carried out for mineral sands companies concerned about low-levels of naturally-occurring radioactivity in their products. Where measured levels of radioactivity have exceeded allowable levels, Ansto has used specialised techniques to identify the source and distribution of the radioactivity and investigated processing strategies to remove the Contamination.

Jan 1, 1993

Full aerodynamic design development of the proposed fans for the enlarged primary ventilation system at Mount Isa Mines Limited was initiated before tender specifications were prepared. Theoretical and analytical design studies were made of many possibilities to determine the optimum proposal. Major considerations were efficiency, simplicity, standardization, and mechanical feasibility. Model testing and experimental work covered blading design, inlet shape, diffuser and tail fairing dimensions, instrumentation requirements, ancl noise studies.Theoretical and predicted performance estimates were prepared for the three 20 ft diameter vertically mounted axial flow fans.

Jan 1, 1967

By BTrubT M

In the roast-leach-electrolysis process for the production of zinc, iron contained in zinc concentrates is converted to zinc ferrite during roasting. At Canadian Electrolytic Zinc (CEZinc), the Outokumpu Conversion process is used to simultaneously leach zinc ferrite and precipitate the iron as jarosite. These simultaneous reactions, while providing good process stability, require a compromise between optimum conditions for maximum zinc extraction and efficient iron precipitation. An improved conversion process has been identified which can achieve >99 per cent zinc extraction and more efficient jarosite precipitation to residual iron concentrations of

Jan 1, 1993

By A Moreira, A B. De Souza, S Latchireddi, E Faria

Material transport plays a significant role in the efficiency of horizontal grinding mills - autogenous (AG)/semi-autogenous (SAG)/ball mills. The magnitude of benefits that can be achieved with efficient material transport in AG/SAG mills has been demonstrated in a greenfield milling operation at Mirabela MineratpoÆs SantaRita Nickel operation located in north eastern Bahia in Brazil. This grinding circuit was commissioned in October 2009, was designed as a typical SABC circuit to grind 4.6 Mt/a (575 t/h) to produce a P80 of 125 ¦m with ten to 12 per cent ball charge in the SAG mill. However, it has been operating as an ABC circuit without any grinding media in SAG mill. The nameplate design capacity was achieved in few days and was gradually increased to an average of +800 t/h, still operating in ABC mode. The Santa Rita grinding circuit consists of one 30 ft + 15.4 ft 8.5 MW SAG mill fitted with Outotec patented Turbo Pulp Lifters (TPLÖ) in closed circuit with a HP400 short head pebble crusher and one 20 ft + 28.4 ft 5.5 MW Ball Mill in closed circuit with a Warman cyclone cluster fitted with 10 + 26 in CAVEX cyclones. This paper examines the comminution design process, operating philosophies, experiences, post commissioning optimisation and future development works. Evaluation of the milling circuit performance relative to the design criteria is also discussed.CITATION:De Souza, A B, Latchireddi, S, Moreira, A and Faria, E, 2012. Application of turbo pulp lifter in greenfield operation - Mirabela SantaRita nickel operation, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 53-58 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By J Brisebois

The derelict Lake George Mine is located at Captains Flat in NSW, acommunity of approximately 450, which lies some 43 km southeast ofQueanbeyan. It straddles the Molonglo River, which flows toQueanbeyan and thence the nationÆs capital, Canberra. Catastrophictailings dam failures in 1939 and again in 1943 resulted in the transportand dispersion of thousands of tonnes of sulfidic wastes downstream,with terminal settling in Lake Burley Griffin, in Canberra. The mine wasclosed in 1962, and major rehabilitation in 1996 - 1997 addressed the riskof further collapses, and reduced water flow into the underground mine.Nevertheless, acid mine drainage from the mine, and seepages ofcontaminated water from the capped tailings dumps continue to pollutethe Molonglo River for some 30 km downstream.Environmentally, the highest contributor to the total contaminant loadof the river is the Main Adit Spring. This was shown to be a constantgroundwater-driven acidic flow, with contaminant generation resultingalmost entirely from the ingress of gaseous oxygen into the undergroundworkings. Long term remediation may be possible at source, by pumpingreducing gases into the sealed mine, but the probability of thistechnology succeeding to the required degree is yet to be demonstrated. For at least the medium term, treatment of contaminated water flow(s)will be required to achieve any of the water quality targets that may beapplicable to the river. Three methodologies were short listed, but anumber of strategic uncertainties remain, which the NSW Derelict MinesProgram will address. Future risk arising from long-term contaminantrelease by the treatment wastes must be considered. Appropriate data,and realistic long-term performance parameters regarding the relativestabilities of water treatment sludges are scarce, and make properevaluation of competing technologies problematic.

Jan 1, 2003