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Grade control is an important factor in the on-going success of a mining operation. Grade control criteria will vary depending on the commodity being mined. Financial considerations determine the actual grade control criteria at any one mine site. Mining and metallurgical capital and operating costs are ultimately used in ascertaining cut-off grades employed in grade control. The metallurgical characteristics of the ore, and ultimately the equipment selection and design of the plant, are based on samples provided by the exploration geologist. Ore variability is an important factor in designing the process plant. Ore variations, outside of those catered for in the design, as well as large ore changes on a daily basis, will impact on the metallurgical performance, and hence the economics of a mining operation. Therefore good liaison between the grade control geologist and metallurgist will undoubtedly lead to a more consistent, and more profitable mining operation.

Jan 1, 1993

By Chisholm J. M

Why go to the CIS? The vast mineral potential of the Commonwealth of Independent States (CIS) has long been recognised, but it has taken the lowering of the iron curtain to open up the region to serious mineral development consideration by the Western World. The advent of a free market economy and the emergence of the Independent States with pressing needs for foreign investment has led to a greatly improved investment climate. Coupled with the desire for some of the more entrepreneurial resources companies to head the wave of investment to the region, this sequence of events has promised a great deal, but delivered only modest progress to-date. Potential gold project development has provided the major focus, for three reasons: the region is highly prospective for gold, gold projects tend to have a relatively lower start-up capital cost compared to base metal and fossil fuel projects and finally bullion or refined gold is more readily transportable and easier to sell.

Jan 1, 1996

By G H. Luttrell

The use of secondary desliming cyclones ahead of froth flotation cells to reject ultrafine (-45 ¦m) particles has become a popular option in the United States for preparing fine coal feeds for froth flotation circuits. In light of this popularity, several experimental studies have been performed at industrial plant sites to develop a better understanding of the impacts of ultrafine desliming on froth cell performance and, ultimately, overall plant performance. These studies included an evaluation of various circuit configurations incorporating different flotation technologies (conventional machines and column cells) as well as different dewatering systems (disc filters, screen-bowl centrifuges, and thermal dryers). The data obtained from these studies indicate that deslime circuits offer several important benefits including lower product ash, reduced product moisture, better froth handling characteristics, and lower capital and operating costs. In addition, case studies conducted as part of this investigation have been used to develop generic guidelines for how deslime circuits may be successfully applied to improve the overall profitability of fine coal flotation circuits for both the metallurgical and steam coal markets.

Jan 1, 2005

SINCE writing the above-mentioned paper, some further indicator cards have been taken from the No. 1 machine, and the writers believe that a reproduction of these cards will be interesting as illustrating the performance of the machine after fifteen month steady running, night and day, seven days per week and twenty-four hours per day, at the average speed of fifty-seven revolutions per minute (see Fig. 1, page 60). For the past twelve months no adjustment have been made in the valve setting, and the only repairs have been in connection with the springs of the poppet valves, and these but slight, the springs latterly having been removed. The cards illustrated were taken with one indicator, and, therefore, are not simultaneous, andmay show to some extent the yariations of individual strokes, and with that qualification may be taken as typical of the machine's average performance.In connection with some feed-water measurements of the winding engines a rough test was run with the two compressors, the Riedler and the Corliss, coupled to the condenser, and running at fifteen and fifty-seven revolutions per minute respectively, with the result of 15.9 pounds of steam per indicated horse power per hour. This result, though only approximate, seems to indicate that the No. 1 machine is running under the guaranteed consumption, and that it is capable of maintaining this under the severe conditions of everyday practice.

Jan 1, 1909

By D W. Airey

Frictional rock bolts are widely used because of their low cost. However, they have a thin wall section that makes them prone to corrosion, and they cannot be relied on to provide long-term ground support. It is difficult to assess the capacity after the bolts have been installed as they can only be pulled out if this has been allowed for during insertion. The questions of how long can the rock bolts function effectively and the effectiveness of various surface coatings, which can have significant cost implications are, investigated in this study.A series of accelerated corrosion tests have been performed on frictional rock bolts. The rock bolts, typically 900 mm long, have been inserted into concrete cylinders produced using a styrofoam insert to create the hole for the bolt insertion. Strata rock bolts with four surface coatings have been tested: uncoated black steel, galvanised, enduro (plastic coated) and coated with a proprietary aluminium/zinc alloy. Tests have been performed on two diameters of bolts. Following insertion of the bolts, the concrete cylinders were placed in a large drum filled with saltwater and current was applied to accelerate the corrosion process. The rock bolts were then extracted at various times after the commencement of corrosion. Comparison of the insertion and extraction resistances shows that corrosion initially increases the bolt resistance and that substantial section loss is required for the bolt resistance to drop significantly.CITATION:Airey, D W, 2014. Laboratory corrosion tests of frictional rock bolts, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 257–262 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By Y Peng, D J. Bradshaw, X Chen

At NewcrestÆs Telfer gold mine, a strategy of regrinding pyrite rougher flotation concentrates has been proposed to increase gold recovery and reduce cyanide consumption in the CIL circuit. The regrinding will be followed by an additional copper/gold flotation stage, where copper minerals need to be separated from pyrite. However, although the minerals are well liberated, the separation of chalcopyrite from pyrite in the cleaner stage is not always straightforward. The surfaces of the fine particles, produced during regrinding, are more easily oxidised and contaminated than coarse particles, directly influencing the particle floatability. The depression of pyrite is difficult in the cleaner stage as well due to copper activation, a process which is also highly dependent on the grinding environment. In this study, different grinding media, including mild steel and stainless steel, was used in the regrinding to produce different regrinding chemistry, such as, pH, Eh, and iron hydroxide contamination. The effects of regrinding conditions on chalcopyrite flotation and its separation from pyrite were studied. It was found that the stainless steel grinding media, which produced an oxidising environment, was more beneficial for the separation of chalcopyrite from pyrite after regrinding. The mild steel grinding media had a detrimental effect on both chalcopyrite and pyrite flotation. This study addresses the importance of choosing suitable regrinding conditions in the pyrite and copper flotation circuit.CITATION:Chen, X, Peng, Y and Bradshaw, D J, 2012. Effect of regrinding conditions on the flotation of chalcopyrite and its separation from pyrite in the cleaner stage, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 279-286 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

Geological models for the exploration and evaluation of epithermal Au and porphyry Cu-Au deposits rely upon a classification of different deposit styles and an understanding of the evolutionary processes of deposit formation. These models guide the interpretation of subsurface deposit anatomy in order to target drill testing and assist the explorationist to focus on the more prospective projects. It is important for the explorationist to distinguish between different styles of magmatic arc Au deposits as each style displays distinctive characteristics with exploration implications. Magmatic arc Au deposits are distinguished as porphyry Cu-Au formed at depths of 1 - 2 km at the apophysis to larger, buried, magmatic sources which are also the ultimate metal sources for the varying styles of shallower level epithermal Au deposits. Low sulfidation epithermal Au deposits characteristically develop from dilute circulating meteoric waters and are distinguished as the group with a closer relationship to intrusive source rocks, and slightly higher sulfide contents (still generally

Jan 1, 2004

By B T. Park, S D. Fundingslan, K W. Wangerud

The EPA National Risk Management Research Laboratory (NRMRL) Mine Waste Technology Program (MWTP) and the EPA Region VIII Superfund office are jointly conducting a field-scale technology demonstration of a two-step in situ treatment of the acidic Anchor Hill Pit lake at the Gilt Edge Mine Superfund site near Deadwood, South Dakota, USA. The project goal is to develop cost and performance data for the in situ treatment for potential application in long-term water treatment/management activities at the Gilt Edge site, and for potential application at other similar sites. Lime neutralisation of the pit using a Neutra-Mill was accomplished in the spring of 2001, with a resultant lime utilisation efficiency of about 71 per cent, and a typical throughput of about 1 tonne per hour using coarse, pebble quicklime and 1.4 tonnes per hour using finer, ground lime. Redox-mediated biotransformation treatment of the pit has been ongoing since May 2001. As of January 2003, denitrification is complete in the near-surface waters and about 90 per cent complete in the deeper waters. Bacterial sulfate reduction is expected to begin in the near future. This paper describes project activities, results, and lessons-learned to-date as well as future monitoring plans.

Jan 1, 2003

By D Chalmers

After the sustained use of the GAG (Górniczy Agregat Gaśniczy) engine at a Queensland coalmine, it has raised questions as to its effectiveness as a remote firefighting tool. All firefighting apparatus have advantages and limitations, however the deployment of any apparatus must be based on its likelihood to succeed and effectively extinguish the fire or bring it under control. A recent study conducted for ACARP by researchers at UNSW has highlighted that there is more to be learned about the GAG. As coalmines are mining at greater depths and fan pressures are much greater than they were when the GAG was introduced, deploying the GAG may be a total waste ofresources and may place operators at greater risk. When the GAG unit is positioned on the surface of the mine, the pressure it generates has to overcome buoyancy of the exhaust gases and the frictional resistance of the borehole and part of the mine circuit. Buoyancy in deeper holes can lead to the GAG pressure relief system opening, venting out the products to the atmosphere without delivering any product to the mine workings. Additionally, frictional resistance is a function of distance. Deeper holes will have a greater frictional resistance than shallow holes. Delivering sufficient products from the unit will be limited by the available pressure that has to overcome the buoyancy, and increased mine resistance thatconsumes any residual pressure. By documenting the limitations of this unit it will enable better decisions to combat a fire or spontaneous combustion event.

Oct 12, 2022

By C Li

Removal of gangue minerals from ilmenite concentrates can beaccomplished by relatively low temperature roasting in controlled gasatmospheres to selectively enhance the magnetic separationcharacteristics of the ilmenite. At roasting temperatures below 800¦C the magnetising reactions are often not consistent with phase equilibria considerations. Metastable phases can nucleate and control the roasting products. In weathered ilmenites the phase assemblages and microstructures in the altered ilmenite grains can influence the roasting reactions. In this paper we give an overview of the phase chemistry of chemically weathered ilmenites and of metastable phases formed by low temperature roasting. We also report the results of roast experiments conducted in a neutral gas atmosphere. Major increases in magnetic properties after short roasting times at low temperatures were obtained for a range of ilmenite concentrates. For example heating a secondary ilmenite concentrate from Western Australia for 15 minutes in nitrogen at 600¦C gave an increase in the three kilogauss magnetic fraction from three to 92 wt per cent. The solid state phase changes accompanying the inert atmosphereroasts were characterised by combining elemental analyses withquantitative phase analyses of the ilmenite concentrates and their roast products. It was found that the phase reaction that is principally responsible for the increase in the magnetic properties of weathered ilmenites involves a transformation of disordered ferrous-containing pseudorutile to an ordered ilmenite-hematite solid solution containing typically ten to 35 mole per cent of the hematite component. Examples are given of the application of the inert atmosphere roast to effect separations of ilmenite from gangue minerals.

Jan 1, 2001

By Gordon N

The in situ behaviour of claystone floors associated with the Wallarah, Great Northern and Fassifem Seams has been studied using a comprehensive suite of stress and displacement monitors. The instrumentation was supplemented by in situ and laboratory testing of the claystone materials. The instrumentation demonstrated that the presence of claystone floors is associated with floor heave, extra rib spall, and settlement of the pillar into the floor. Horizontal floor extensometers showed that the depth of extrusion of clay was limited to 1-2 in. A pore pressure transducer installed in a claystone floor demonstrated the possible existence of short-term undrained behaviour of the claystone. Long term swelling of destressed claystone was also documented. Settlement of pillars into claystone floors can be analysed using simple elastic theory. The assumption of plane strain is valid for most claystone thickness/pillar width aspect ratios. Floor heave can be analysed using bearing capacity concepts. However, it is considered that heave is the result of local bearing capacity failure in the rib spall zone. The advantage of this model is that the bearing capacity equation can be applied without resort to unrealistically high factors of safety.

Jan 1, 1992

By McClarnon D. J

This paper aims to provide the reader with an insight into the field of computer graphics and Virtual Reality (VR), and show how both have been applied to the general area of Free Steered Vehicle (FSV) operations underground. It first explains this developing computer technology and explains its advantages over existing CAD based solutions. This paper deals with the graphical applications and implications of building models within a computer's memory. It then continues to describe the problems with Free Steered Vehicle operations. The work already carried out in the field of VR is explained, and the production of a VR system addressing the problems with fitting cameras to aid the driver's field of view is detailed. Another possible use of VR is also explained - the concept of risk regions, demonstrating its uses in the examination of proposed operational methods. Examples of possible uses are given, and its potential advantages over existing methods discussed. A case study of a computer-generated video involved with the safety of operations of FSVs is also presented. This addresses the precautions that pedestrians should take to ensure safe working in areas where FSVs are operating. This paper then concludes with possible further applications for computer graphics and VR, and the on-going research into these two technologies.

Jan 1, 1995

Explosives have been an important tool for unlocking minearl wealth from the earth's crust for several countries. In'the past, innovation in explosives technology, spurred on by industry needs has assisted the Mining Industry to improve productivity and reduce costs. A symbolic relationship exists between Explosives and Mining. Australia has vast mineral wealth. Our Mining Industry is of major importance to the Economy., The value of mineral produc- tion in 1987 was $25 million or 10% of GDP. Australian Mining is a business depending on international markets. The Mining Industry is our leading export earner, generating 44% of all export income. 60% of mineral production is exported. About half of these minerals are extracted using explosives. Explosives rank as one of the top three consumable expenditures for a mine. For example: A major open-cut iron or coal mine can spend $6 million dollar per annum on explosives.

Jan 1, 1988

By M Maulen, K van Olden, T Elkington

A large open pit is planned at the site of an existing underground mine. Strategic planning work has been undertaken to investigate the project value associated with an expansion of underground operations in conjunction with the proposed pit. Previous analysis determined that any depletion of the available pit resource that changes the optimum pushback sequence has a significant negative impact on overall project value. Therefore, to investigate the viability of an underground expansion requires a system to identify the stope resource that would add value to a combined operation if mined ahead of the pit. The key solution to this problem was to generate a resource model variable that defines the blocks, which have greater discounted value if mined by stoping rather than by the open pit. A key assumption was that the open pit is the main driver of overall project value. From the identified potential underground resource, series of mineable stope shells were generated at a range of cut-offs. This stope reserve data formed the input to a mixed integer program based software tool that was developed and used to optimise the underground mining plan, at conceptual level, for various project configurations. A dynamic programming tool was then applied to evaluate the optimum value of a combined open pit and underground operation. The overall objective of this project was to determine the strategic plan that yields the optimum value for a combined undergroundûopen pit operation. The results provided a clear focus and direction for more detailed design and planning.

Jan 1, 2009

During the last 20 years, manufacturers of Australian iron have given increasing attention to development of external markets for processed blast furnace slag. Slag has been in widespread use overseas and data on the performance of Australian slag in concrete lave shown it is suitable for that use. Chemical and physical properties of typical Australian slag products including air cooled, granulated and pelletised slag are discussed and compared with local natural aggregates. Special attention is given to pumping achieve- ments with slag concretes and the observed durability of concrete after many years service. More'recent applications for granulated slag as a sand replacement are discussed. It is concluded that'whilst more wide- spread use of slag is possible, the cost of marketing and transporting slag are likely to restrict opportunities unless for local usage.

Jan 1, 1979

The object of this paper is not to describe any particular type of engine in close technical detail but rather to give a general picture of past and present practice in this important section of the industry. The subject involves the study of almost 600 years of coal mining history which has fluctuated from stagnation to extremely rapid progress.Up to the year 1300, coal was obtained from outcrops and exposed beds, but this easily worked source soon gave out, so by that time shafts had to be sunk to the coal seams, and coal mining proper commenced its career.These early shafts were very shallow, and winding equipment was not a matter for much concern. Raising coal was generally achieved by human labour, which was called "coal bearing." Coal was loaded into baskets. strapped to a man's back, and carried from the underground workings to the pit bottom. The unfortunate individual then climbed ladders to the top of the shaft, unloaded the basket, and descended the shaft for the next load. Men, women and even children, were employed as the mine expanded, and were generally bound to the colliery for life, performing daily work which would now be regarded as slavery. This primitive method of raising coal to the surface was slow, inefficient and highly dangerous, yet for want of a better method it continued until in 1602 it isrecorded as having been abolished in Wales, one of England's great coal districts. It was not until 100 years later, however, that it was abolished in the northern coalfields, and the colliers were freed forever from their dreadful life.WINDLASSThe first step towards winding coal was the introduction of the windlass. This was similar to the common windlass used over a well, and was operated by man power. The...

Jan 1, 1945

By Sergeant G. D, Norman J. R

The importance of reducing the moisture content of fine coal, the nature of the retained water and the means of its removal are discussed. A statistical technique, using a balanced block design, was used to isolate the significant factors determining water content of a coal filter cake, The most significant factor was particle size distribution. A simplex evolutionary operation (evop) was used to determine the optimal quantities of additives required to produce the lowest moisture content for a selected coal size. For this optimum condition (18.6 lb xÇ20 per 100 lb dry coal), additions of 0.045 lb magnesium ion, 0.0026 lb separan A.P. 30, and 0.098 lb aerosol O.T., per 100 lb dry coal were required. The work illustrated the uses of statistical evop technique for the determination of optimal conditions in industrial research projects.

Jan 1, 1969

Blasting is known to be both an important and an easily quantified cost factor in rock breaking operations. However, the indirect costs and benefits of the blasting operation are not easily determined due to the irreversibility of the mechanisms involved and the multiplicity of influencing factors. A general conceptual model showing the relationship between blasting and mining costs is well known, but serious attempts to address the critical real relationships have all floundered on the fact that not enough is yet known about either detonation physics or blasting effects. This can only be remedied to the extent that blasting instrumentation enables researchers to pin down not only the relationship between the detonation process and its impact on a particular environment, but also the downhill costs of handling the rock, repairing any damage and building in "Safety Factors" to provide for imponderables. It is vital to standaraize on specifications for instrumentation and measurement techniques and there is a need to review what has been achieved in blasting expertise so as to focus on the most fruitful paths for future work.

Jan 1, 1990

By Wu Y, Qu Q

The Central Coal Mining Research Institute has developed the MAE acoustic emission monitoring system, the BD4-1 portable acoustic emission monitor and the MRB rock burst monitoring system. In the MAE system there is an IBM-PLAT, a receiver and 16 channels and the investigating range is 100 m. The main functions are detecting acoustic events from the working faces, periodically making statistics, prints, displays and storing of the results, and performing the off-line process such as drawing the curves of acoustic activity. The BD4-1 instrument has four channels, it works for more than 24 hours continuously, and keeps the data for more than 30 days after power tum-off. The BD4-1 is suited to the monitoring for a long or a short time as a fixed point where the system is invalid, especially to the monitoring of the acoustic activity promoted by the blasting. There is an IBM-PC/AT, a receiver and 16 channels spread 10 km in the system MRB. The system could on-line collect microseismic events throughout the whole mine, calculate the source location and the energy, and off-line draw the seismic activity draft of time-based or distribution in space. In practice, the forecasting is successful by using the acoustic emission and microseismic monitoring system and the portable instrument.

Jan 1, 1991

It is difficult with inadvertent explosions to establish fundamental data, especially of original dust, of pressure, temperature etc. and of ventilation oscillations, as exposed personnel rarely survive. Retrospective data from explosions must be derived from damage, from fatalities, from ventilation analyses, from analyses of dusts and other indications of temp- erature and duration of temperature. The five disastrous explosions selected for analysis provide examples of what data can be established as to the cause and extent of explosions. Such information is required for legal etc., inquiries subsequent to explosions, but most importantly to give the best guidance for avoidance of possibility of further Disasters.

Jan 1, 1981