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By C Deacon

It is common practice to include microspheres or similar density reducing agents in inherently insensitive water-based commercial explosives to achieve detonative sensitivity in the absence of chemical sensitisation. It has recently become possible to similarly include microspheres in LDAN (low density ammonium nitrate). Further to previous studies and publications to determine the benefits resulting from the use of microsphere enhanced LDAN technology in blasting, additional advantages are described in this document. These include range tests at independent testing facilities (Universal Tech Corporation û USA) which reflect results observed in the field, and support theoretical assumptions made when the products were introduced. Additionally, on-site studies in opencast pits using Heavy-ANFO blends incorporating modified LDAN, show that monetary savings can be realised through significant advantages gained in plant throughput and explosives use.

Jan 1, 1999

The drilling and evaluation of bore cores provides the best available statistical basis for characterizing a coal prospect. Important, long-term decisions by management frequently must be based on the results. The majority of coal mined presently is used for steam raising or the production of metallurgical coke. Common bore core tests and analyses appropriate to this usage can be cate- gorized as non-destructive, chemical, physical, petrographic, caking/plastometric and propert- ies of non-coal material. The major tests within each category are described. Certain specific information from the bore cores is required by the coal geologist, mining engineer, coal preparation engineer and the user, either individually or as a group. The optimal bore core evaluation test pro- gramme is the one which satisfies the needs of all the professional disciplines with the grtatest speed and at minimal cost. The principal steps in such a programme are listed. There is an urgent need for a bold new Australian standard to provide the necessary guidelines to an industry which at present lacks uniformity in its approach to the task.

Jan 1, 1977

Financial theory often takes some time to penetrate industry and when it does it can result in a paradigm shift in valuations and mental models. The Black Scholes option valuation was first published in 1973, although the authors were only awarded a Nobel Prize in 1997. The valuation of real options has been applied to the oil and gas industry for some time, however it has only recently been more widely applied to the non-oil, mineral resource sector. The use of real option valuation (ROV) for the valuation of marginal and short mine life resource projects is a more useful valuation tool than the conventional DCF, NPV valuation tool. The application of ROV has major implications for corporate strategy. It generally favours equity over debt funding and non-hedging over hedging. A retrospective assessment of the successful development of the Lennard Shelf Operations demonstrates the concepts of implementing real options and the value destruction of limiting operational flexibility through debt and hedging activities.

Jan 1, 2003

By Tomlinson R. C

The paper will briefly describe planning in the National Coal Board (NCB) and the contribution that operational research makes to it. It will then give details of some of the models in use and will finally consider critically the problems of looking ahead to the next century.

Jan 1, 1977

Both innovation and excellence are desirable attributes of education, as they are also markers in the progression of the human race, but how attainable are they? The interaction of minerals and humanity provides a special insight into the development of both criteria, from the discovery that chert cuts, through the Bronze Age and the first use of metal alloys for implements, to using coal, oil and uranium as sources of fuel. However, there have been many hiccups along the way, where excellence in one respect has meant disaster in another. Examples are in the exploitation of asbestos, and in traditionally poor work practices in mining, both contributing to the widespread public belief that minerals and mining are ecologically undesirable. Yet is this perception based on the unrealistic expectation of innovation and excellence being simultaneous qualities of any given process? Common sense born of experience indicates that the journey from one, to the other, is usually a long and often tedious process, with much trial and error before excellence is attained. In our time, the partnership between academia and industry is the usual pathway to achieve it. Even so, we should take care that innovation does not become overwhelmed by the pursuit of excellence: as history clearly demonstrates, humanity depends upon both.

Jan 1, 2004

By Groves J

The sizing and classification circuits at the Mt. Newman Beneficiation Plant have performed satisfactorily. Investigations have been aimed at solving minor problems and achieving small' improvements. Emphasis has been placed on cost reduction rather than metallurgical performance. It has been found that some circuits will give better performance with the sieve bends removed. 1.0 BACKGROUND Mt. Newman. Mining operates a major iron ore mine in the Pilbara region of Western Australia. Rainfall is sparse (average 250 mm/year). Current mining is all above the water table. What rain there is tends to run off quickly instead of soaking in. The total operation produces about 30 Mt/ year of saleable product. Most of this product comes from high grade crushing plants where ore from the quarries is simply crushed and conveyed to product stockpiles. About 3 Mt/ year comes from the Beneficiation Plant.

Jan 1, 1984

By J-M Rendu

Substantial progress has been made over the last ten years in the development of uniform national and international standards covering the definition, estimation and public reporting of mineral resources and mineral reserves. Agreement between the major participating countries has been reached, which includes the requirement that a Competent Person prepare and approve publication of mineral resources and reserves. Most national regulatory organisations have accepted the new standards and have included them in the rules that must be followed by mining companies operating under their jurisdiction. These developments are the result of a concerted effort on the part of professional societies, national regulatory agencies, international organisations, and many dedicated individuals. The historical development of these standards is summarised in this paper. Accepted definitions of mineral resources and mineral reserves are discussed, as well as the definition and role of the Competent Person. Additional effort is needed before the international standards are fully understood, accepted and followed by mining companies, regulatory agencies, the investment community and the general public. Steps being taken toward development of an International Code are outlined.

Jan 1, 2002

Research and Technical Services, Department of Mines Western Australia The nine papers received for this technical session cover a very wide range of hydrological problems in various parts of the world. Three of these papers deal with hydrological predictions for new mines, while three are concerned with the prediction of water chemistry. The three remaining papers deal with gas injection as a dewatering tool, discharge formulae verification and the use of a physical model to predict subsurface strata movement and fracture development due to longwall mining. Hydrological problems in mine planning represent a major risk in many mining operations, booth as a potential life or equipment hazard and a major financial risk. The initial paper selected to review was therefore one by the president of a gold mining company, rather than by one of the specialist scientists, to remind us all that the main reason problems are faced and overcome in the mining industry is usually a commercial one. In one commercial undertaking, the ability to accurately assess future risk is a highly desirable planning tool and hence in mining, the ability to predict the nature and magnitude of hydrological problems is n i-an varxi imnnrfant

Jan 1, 1988

New Zealand's Land and Income Tax Act 1954 contains unique incentives for companies engaged in mining certain specified minerals or petroleum. Sections 152 and 153 provide for the taxable income of such companies to be based not on profits made but on dividends paid to shareholders. A significant saving in tax results, particularly where profits are not distributed: but the Act attempts to ensure that undistributed profits are used for further mineral exploration and development. To encourage investment in the mining industry, persons taking up shares in a company mining for the specified minerals or petroleum are entitled to a one-third deduction in respect of monies paid on the shares and used by the company for its purposes; and company shareholders may make loans to the company and write-off such loans for tax purposes to an amount of up to half their taxable income. Maximum utilisation of the tax incentives calls for careful consideration as to whether a mining or petroleum company should be financed by way of loan capital or share capital.

Jan 1, 1971

By Reimer TH

The model described in this paper has been developed for and in close collaboration with the Bong Mining Company Ltd, Liberia/West Africa. When working an irregular deposit a de- tailed short term production schedule becomes necessary in order to ensure an equal and homo- genous concentrator feed. If the irregularity of the ore body exceeds a certain degree, blen- ding facilities have to be provided between the mine and the concentrator, but even then sche- duling of the mine production is inevitable to meet the given requirements of the blending bed and to keep these conditions steady for at least some of the successive periods. To assist the planning department in set- ting up optimal production schedules a computer model has been developed using a linear pro- gramming approach. The deposit is divided into equally shaped blocks containing defined quali- ties and quantities of ore and/or waste; from which one has to select those quantities of ore which will meet the requirements of the blen- ding bed. The objective function of the model

Jan 1, 1977

This subject of paramount importance in many modern plants employed in the extraction of gold from ores by cyanidation, involves several considerations.With the old-type "slimes decantation" process, using several tanks of large dimension, installed at high capital cost, it was frequently possible to obtain good settlement over a protracted period, but the disability of indifferent response to subsequent filtration and washing of the residual pulp, after decantation of the supernatant pregnant solution, was often present.In modern cyanidation practice, the tendency is to reduce capital expenditure by continuous processing of the ore pulp in a plant of less volume, but capable of handling more tonnage through-put and yielding, coincidently, less residual dissolved gold in the final pulp residues.INHIBITORY FACTORS.These involve a study of the effect of the circuit water or solution employed in milling and treatment, the amount of "primary" slime occurring in the ore broken underground, the constitution of the "walls" underground, the inherent occurrence of colloidal slime in partially decomposed ore, and the presence of kaolinised and ferruginous clayey structures carrying payable infiltrations of gold values, to mention some of the troubles encountered in practice. Practically all the difficulties occurring are due to the presence of colloids (using the metallurgical as apart from the chemical definition of the term), either...

Jan 1, 1935

The Mining Act (1992) and the Petroleum Act (1980) provide for the Government of Papua New Guinea (PNG) to take up equity holdings in mining and petroleum projects. The price the Government pays for its share is based on the historical cost of exploration and development on the project to the date of government equity acquisition. The equity level to be acquired is not fixed and ranges up to 30o for mining and up to 22.5s for petroleum at the discretion of the Government of the time.The objective of this paper is to examine the pros and cons of State equity holdings in PNG from the point of view of both the State and the developer. Using an economic model of the PNG mining taxation system an assessment is made of the effective return on investment received by the State from such equity holdings. The results are compared with government revenues from other taxation measures.

Jan 1, 1994

The Curragh mine has complex operating conditions. The mine operates in four seams to produce two coal qualities and is divided into five pits which have different qualities and coal preparation characteristics. The combination of all of the necessary controls to achieve maximum resource utilisation has necessitated the development of suitable software to assist the quality control engineering function. The required software had to be able to plan the optimum yield of coking coal whilst achieving the quality parameters for the coking coal and co-produced steam coal. The program has been designed to evaluate all of the mine faces available for coking coal production. The optimisation of coking coal production is planned and co-produced middlings steam coal determined. The optimum steam coal product is determined using the middlings in combination with bypass production.The computer software to carry out these functions has been designed by using an exploration data base as the raw data source. The program accesses this data and uses a coal preparation prediction program to determine the yield vs. ash relationship for each coal face. A linear program selects the optimum -combination based upon equal incremental ash values. The final output lists feed tonnages, coal preparation conditions, product tonnages and full coal quality data.

Jan 1, 1985

By G L. Simmons, K M. LeVier, R Kappes

The low potential hydrophobic state of pyrite in amyl xanthate (PAX) flotation with nitrogen is of particular interest with regard to the N2TEC flotation technology currently being used for the recovery of auriferous pyrite at NewmontÆs Lone Tree Plant in Nevada. Initially, the N2TEC system had been found to operate satisfactorily, but cyanide in the flotation mill water appeared to be responsible for a loss in pyrite recovery. This supposition was confirmed with laboratory experiments, and a program was initiated to study flotation chemistry variables by electrochemically controlled contact angle measurements. Experimental results show that activation of pyrite in such cyanide solutions can be achieved more effectively with lead than with copper. Subsequently, based on these fundamental studies, significant improvement at the Lone Tree Plant was achieved by lead activation, in which case the recovery increased to expected levels. The effect of activator is particularly significant not only with respect to pyrite depression by residual cyanide, but also with respect to collector (PAX) consumption and the initial state of the pyrite surface. Experimental results show the importance of the pyrite surface state and the rather interesting features of the activation process.

Jan 1, 2005

The implementation of the Mining Further Amendment) Act, 1970, and later the Coal Mining Act, 1973, placed a requirement on the Department of Mines to accept an initiative in relation to coal exploration and coal mine development which does not apply in the case of other minerals. It is necessary to consider the exploration of the total coal resources of the State when considering exploration rather than one individual basin or deposit. If the level of knowledge of the coal resources in these basins is considered in relation to their potential for development it is possible to allocate broad scale priorities to their assessment. Due to the enormity of the task which involves a conservative estimate of in excess of 400 000 m of drilling to reach a broad reconnaissance level of understanding the involvement of industry with the Department in the exploration programme is necessary. The development of the coal deposits by mining operations must give consideration to a number of constraints apart from the simple availability of the resources. Principal among these are aspects

Jan 1, 1976

By Lane G

This paper addresses project commissioning, that is, activities that culminate in the transfer of a project from the construction phase to routine plant operation. These activities should be initiated early in the engineering and design phase to ensure that the plant design is operator friendly and that construction is scheduled such that pre-operational testing and hand over to the owner occurs in a timely and cost-effective manner. For the purposes of this paper, commissioning includes all activities related to pre-operational testing, no-load testing, water commissioning, and ore commissioning. That is, all activities from construction completion to practical completion of the prime contract. This process is facilitated in numerous ways dependent on the nature of the project prime contract and the size of the project. For small lump sum projects, the contractor's responsibility may include all phases of commissioning to practical completion, whereas, a managing contractor on a complex multi-contract project may only be required to bring the project to mechanical completion and hand over to the owner for ore commissioning. Irrespective of the responsibilities, commissioning programs require careful planning, effective communication and detailed reporting. Unsuccessful

Jan 1, 1997

In the time since the first trials in the mid-1980s, the Rare-Earth Magnetic Separators (REMS) are presently (year 2001) found in many heavy mineral sands plants around the world. Both the roll and the drum type are used from ilmenite concentration to cleaning high-purity zircon products. Chromium-bearing materials are removed from ilmenite more selectively than with electromagnetic separators. Greater flexibility and higher grades in ilmenite circuits are achieved. Cleaner rutile and zircon products, even with respect to levels of radioactive materials, are the result of superior magnetic force optimisation. Tailings from roaster plants can be reprocessed effectively, which is encouraging some operators to look at replacing old equipment in order to process roasted material plant feed or implement use of the new generation drum separators in new plants. Wet separation of ilmenite by using powerful wet REMS drum separators is now a possibility. This may be an alternative to at least a portion of the Wet High-Intensity Magnetic Separators (WHIMS) process for ilmenite preconcentration. A dry plant process flowsheet can often be modified by displacing a portion of high-tension separators with new high-temperature tolerant REMS.

Jan 1, 2001

By G Lind

Bridging of production stopes in narrow vein gold deposits contributes to significant financial losses and production delays. Bridging is caused when underbreak in the stope production blast occurs, resulting in less than the designed stope blast volume breaking out during blasting. Jundee Operations in the Northern Goldfields of Western Australia extracts ore from its expansive narrow vein orebodies utilising longhole open stoping. In 2006 it experienced bridging in ten panels, or 8.77 per cent of all panels, as well as multiple bridging in 30 per cent of these bridged panels. The Jundee orebodies are west dipping with the bridged panels dipping between 44¦ and 62¦. This paper examines some solutions from the drill and blast design perspective to minimise bridging occurrences. It was found that the then current drill patterns and number of holes were adequate from a longhole stope design perspective. However, changes to the blasting design, specifically modifications to the blast delay initiation sequencing, primer positioning and blasthole dump combined with timely stope surveying and back analysis, were implemented with the aim of preventing bridging in this narrow vein operation.

Jan 1, 2008

By P O. Andersson

Mining of sill pillars is more difficult than the ordinary mining. The sill pillar mining is performed under more difficult conditions and the mining of the sill pillar itself produces more problems; failure of the rock due to high stresses, difficulties in controlling the fill above, overall stability of the stope and special requirements on the technique for backfilling. Altogether this makes sill pillar mining technically difficult and often not profitable. A project was therefore initiated with the aim to increase the mineable ore reserve by making sill pillars mineable, both technically and economically. The project aimed at developing technique for already existing sill pillars as well as planned sill pillars. For the existing sill pillars a technique would have to be developed for mining beneath unstabilised fill. For sill pillars that would be created in the future, the most suitable mining method and methods of supporting or stabilising the fill in the stope above was to be chosen within the project.

Jan 1, 1998

The risks faced by organisations are part of a risk continuum. They can be evaluated in terms of hazard, uncertainty and opportunity as well as by the degree of influence they have on conformance, operating performance and strategic objectives. This paper discusses the application of risk management techniques for mitigating blasting hazards, reducing blasting output variability, and implementing blast improvement opportunities. Effective risk management practices can identify and evaluate risks across all levels of the continuum and can deliver realistic assessments of the likelihood and impact of risks on the companyÆs safety and business objectives. This paper does not attempt to present technical details about blasting, rather it aims to provide enough blasting context and examples so that the practical benefits of applying the risk management process to blasting can be fully appreciated. The topics discussed include: explosive management plan; statistical process control; quality blasting, rock-on-ground; Blast Management; Mine to Mill optimisation; and blasting information systems. The concept of a blasting risk management system employing a continuous improvement loop is also introduced. On reflection the insights presented should be extremely useful for observing and understanding which risk face has management focus at a mine site or for a blast site.

Jan 1, 2001