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A device is described which is suitable for the automatic sampling of dust in dust laden flue gases. This device, called a Venturi Sampler, consists of two pipes each fitted with a suitably designed venturi.Both pipes are placed in the flue where one acts as an open-ended reference tube and the other as the actual sampling tube.The gas sampling rate is automatically controlled so as to maintain a zero differential pressure between pressure tappings in the two venturi throats. The venturies are so designed that under these conditions the gas velocity in the sampling pipe is always equal to the free gas velocity in the flue-that is isokinetfc sampling conditions are maintained.INTRODUCTIONThere is a constant need in industry for regular and accurate assessments of dust losses, both to assist in improving operating efficiencies in order to minimize losses, and to obtain accurate metallurgical balances. In many cases where sampling is carried out in dust laden gases, the existing sampling methods are both laborious and inaccurate, and often make no provision for changes in flue gas velocity while sampling is in progress.In the majority of cases where a measurement of dust losses in a stack or flue is required, a preliminary velocity survey is made with a pitot tube to establish the gas velocity at each of the points at which samples are to be taken. The sample of gas (and dust) is withdrawn through a tube connected via a flowmeter to an exhausting apparatus. Some means of removing the dust from the gas sample is placed in circuit ahead of the exhausting apparatus. This is often an alundum or paper thimble housed in a gas-tight container.The purpose of the flowmeter is to measure the actual flow of gas during sampling so that the sampling velocity at the inlet to the sampling tube may be calculated, and the flow corrected so that the sampling velocity will agree with...

Jan 1, 1959

By A. Rödfalk, P. Bloemer, J. P. Nilsson, N. Brogden

"Reliable and accurate metal transfer information during silicon tapping from an EAF is invaluable for decision-making and process optimization, while obtaining such information safely is a necessity.Elkem Thamshavn Norway, a producer of metallurgical-grade silicon, identified inherent safety problems with gauging fill levels in ladles using dip bars while molten metal was continuously pouring from a rotating EAF. Operator safety was a paramount concern, and an alternative automatic method of controlling the tapped fill level needed to be found.It was also considered that further benefits could be achieved such as monitoring the tapping flow from the EAF in order to identify any clogging, as well as the potential to use the live feed from such a system to assist decision-making regarding work around the taphole area.Agellis Group AB, Sweden, a company with over 30 years of experience in gauging molten metal levels in the metals industry, was able to design a solution for Elkem Thamshavn that would provide the required real-time process data while enhancing operator safety.This paper shows how the Agellis AB EMLI-L system was successfully installed at Elkem Thamshavn’s EAF continuous tapping area, how ladle fill levels were constantly monitored, and how full ladles were replaced by empty ones without the need for operators to be in the tapping area to take level readings. The results were used to compare the accuracy and reliability of Elkem Thamshavn’s current measuring methods with that of the EMLI-L system. The paper also covers how problems such as how to connect, run, and protect cables in and around the EAF tapping area, as well as connector and cabling survivability during the three day refractory pre-bake period, were solved. Finally, the paper discusses the potential production improvements, maintenance requirements, and data integration attainable through the installation of the system, as well as the major safety improvements that have been achieved."

Jan 1, 2014

By S C. Labram, A Stabile

"Modern train load out stations are becoming faster and have the ability to load a 100 wagon train in less than three hours. At 70 metric tonnes per wagon, that is an average fill rate of 2333 t/h and considering the train is continuously moving, the instantaneous feed rate into the wagon is in the region of 4200 t/h.The main feed conveyor that maintains the level in the surge hopper, above the final weigh hopper, operates in excess of 5000 t/h to ensure uninterrupted charging of the weigh hopper to not disrupt the train loading operation.To avoid demurrage costs (a charge by the Rail Operating Company for exceeding the contractually agreed loading time) the train has to be handled speedily and efficiently and spend the absolute minimum time at the loading facility. Everything else has a much lower priority, including sampling.Thermo Fisher Scientific’s brief was an engineering, procurement and construction management (EPCM) contract to provide a sampling scheme adjacent to the prepurchased and predesigned load-out facility, but which interfaced seamlessly with the loading system of the trains and provided the following: an instantaneous particle size distribution (PSD) result for each truck loaded, and a final PSD for the total train prior to the train leaving the loading facility a crushed (-3 mm) composite sample for chemical analysis for the whole train a composite physical analysis sample for the whole train.The design presented some interesting challenges to our team, but the end result is a system that not only ‘stands alone’ but interfaces seamlessly with the loading system. This paper discusses the design itself and potential improvements to future systems.CITATION:Labram, S C and Stabile, A, 2017. An automatic sampling methodology to determine contractual particle size distribution in rapid train load out stations, in Proceedings Eighth World Conference on Sampling and Blending, pp 229–234 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

May 9, 2017

By C. G. Tester

Automatic tripper control systems can be reliable and as such are suitable for use in the mining industry. Proper application of fundamental engineering principles provides the means for the reliability. Some of the principles are: (1) Be sure the system designer designs a system that does the job operations people want done; (2) Use sound logic design practices to avoid internal electrical problems; (3) The design must be maintenance oriented; and (4) Use good quality components. I would like to discuss a tripper control installation at Kennecott Copper Corporation, Chino Mines Division, in Hurley, New Mexico, and how these principles apply to this tripper control system. First, however, I will expand on the principles to clarify just what is meant. First, "Be sure the system designer designs a system that does the job operations people want done.? Operator acceptance is often the key to the success or failure of an automatic control system. One of the best ways I know of to get operator acceptance is to give him a system that he wants. I don't mean to imply that if bad practices or procedures exist that they should be incorporated in the control system. I do think that many designers feel they haven't done their job if the control system doesn't do things drastically different than the old manual method. Good engineering principles dictate that the job should be done right and if the manual method was right it can very likely be right for the automatic method.

Jan 1, 1973

By Dick T. Atkinson

Due to improvements in the safety of other aspects of mining (primarily in roof control), haulage related accidents, particularly rail haulage accidents, are about to become the most common category of hazards causing death and injuries to underground coal miners. The major causes of these accidents are collisions between vehicles, men caught between rib and trip or between cars, derailments, and runaway cars. Such hazards can be greatly reduced if the motorman has the capability to selectively couple and uncouple cars from the cab of the locomotive, to transmit braking intelligence to the coupled cars, to determine if the trip is intact, and if brakes are automatically applied in any uncoupled car. These capabilities can be provided through an improved coupler system, designed and built by Foster-Miller Associates under a Bureau of Mines contract. Early in the program, a survey of rail haulage patents and literature was conducted. Manufacturers of couplers, mine cars and braking systems were contacted and information relevant to the remote control mine haulage application was collected. From this information evolved a working specification and a design concept. The key elements of the specification, shown in Table I, are the result of a detailed tradeoff study and considerable thought given to the specific problems encountered in the mining environment. A brief explanation of each element is as follows: Automatic Coupling - The couplers operate similarly with most already in underground use - they latch together when a trip is backed into a car intended for coupling. Remote Uncoupling - From the locomotive, the motorman can decide how many cars are to be uncoupled, operate the appropriate controls, and the desired coupler is opened.

Jan 1, 1977

By David A. Fawcett

An auxiliary cross-pit mining system, working in tandem with the prime excavator, is evaluated technically, operationally and economically for application in the selective removal and replacement of soils and unconsolidated ovezburden. Previous studies on cross-pit technology and applications of this technology are briefly reviewed. Stratigraphy plus pit, operating and economic parameters are assumed and applied in the evaluation and comparison of a base case dragline system with two alternatives - a dragline/scraper-dozer combination and a drag- line/cross-pit system combination. The economics of the proposed cross-pit system favour it as a viable alternative to conventional systems.

Jan 1, 1981

By P. Ying

An auxiliary system connected with SEM-EDX for rapid identification of mineral and rock sample has been developed. With the aid of a synthetic spectrum library created, using the compare and match techniques provided by INCA software in EDX the mineral or rock sample names for refer-ence can be given at the same time analyzed.

Jan 1, 2014

By D. G. Millenbruch

An account is given of a four-phase system for the appraisal of a mineral project while it is still in the exploration stage, and for continual consideration of a favourable appraisal until the production stage is reached. There are ten stages from the idea of a likely project to the production stage, and all the staff that are eventually to be concerned with the development of the project are involved at an early stage.

Jan 1, 1979

By J. C. Branner

(New York Meeting, February, 1012.) DURING the past two or three years I have seen statements regarding the first discovery of fullers' earth in this country that seem to require correction or modification. One appears again in the Mineral Resources of the United States for 1909, part II., p. 738, where it is said that ? fullers' earth was first discovered in the United States at Quincy, Fla., in 1893." In this connection the following bit of unpublished history concerning fullers' earth in the State of Arkansas is worthy of attention. In April, 1891, when I was State Geologist of Arkansas, a Swede named John Olsen, formerly a copper-miner in Michigan, but then living south of Little Rock, brought me a sample of what he thought was fullers' earth. He reported that it was from near the town of Alexander, the locality being 1 S. 13 W., section 8, SW. quarter of the SE. quarter. My chemist, Dr. R. N. Brackett, analyzed the material, and reported: Per Cent. Silica, . . SiO2., . 63.19 Alumina, . AL2O3, . 18.76 Iron, . Fe203 7.05 Lime, . Ca0 0.78 Magnesia, . . MgO 1.68 Potash, . K2O 0.21 Soda, . . Na2O 1.50 Loss on ignition, . 7.57 100.74 Water at 110° to 115° C. = 7.84. Another sample from about the same locality, also brought by John Olsen, on analysis by Dr. Brackett gave

Jul 1, 1912

By D. Noon

Mine production crews and drill-and-blast crews may be exposed to unexpected movement of ground when working under pit slopes. Without specialist geotechnical advice and appropriate measurement systems, mine crews are faced with conducting risk assessments and relying on subsequent controls that may or may not be adequate to ensure their safety. Mine crews need an ?early warning? monitoring system to give them the confidence that they will have time to walk out of the danger zone if the pit slope begins to move. Slope stability radar technology is used by mine geotechnical engineers to assess overall slope stability over an extended period, typically days or weeks, and to critically monitor slopes that are actively moving and may become unsafe. The complexity of slope stability radar allows for geotechnical engineers to assess movement types and movement rates across multiple work areas of a mine from long ranges, with alarm capability to a central location. However there are many mine work areas where production and drill-and blast crews are not adequately covered or alarmed by slope stability radar systems. What is required is an easy-to-use, short-range, fast-scanning tool that can be operated directly by a work crew and can provide a local alarm with sufficient warning when a wall movement occurs within the work area. The Work Area Monitor (WAM) concept has been developed specifically to be operated by a mine production crew. The system comprises a sensitive, fast-scanning radar coupled with a high-resolution camera, built into a mine-standard light vehicle. The system has been designed specifically for ease of use with the output being a local area alarm to warn workers of slope movement in their vicinity, as opposed to the broader pit monitoring and long-term deformation measurements of the known slope stability radar systems.

Jan 1, 2012

By R Wheeler, E Stalenberg, J Lemon, M S. Crowther, D Lunney, K Ross

Gunnedah, in north-western New South Wales (NSW), including the town, the surrounding Liverpool Plains and the Pilliga forests to the west, are currently the subject of intense mining interest for coal and coal seam gas. Achieving positive outcomes for koala conservation on mined landscapes will require a sound grasp of koala ecology; and local knowledge of koala movements, tree choice and associated threats to the continued survival of koalas, particularly roadkill from increased mining infrastructure. This requires a research-oriented approach to testing ideas applicable to the long-term survival of koala populations. Our recent koala research in NSW has shown that, in 2006, Gunnedah had the largest koala population west of the Great Dividing Range, and the only population in NSW that was expanding. That prompted us to instigate a detailed study in 2008 - 2011 to determine, inter alia, whether the koalas were using trees that were planted in the 1990s to cope with rising soil salinity. Our GPS-tracking has shown that regrowth trees as young as ten years old can attract koalas. In 2009, the demise of about a quarter of the local koala population from an intense heatwave gave us a foretaste of how habitat and climate change interrelate at the landscape scale. We are now examining the optimal combinations of tree choice, and patch size and shape, for habitat restoration. This will be relevant to local coal seam gas and coal mine proposals, and ongoing mitigation actions. The Senate enquiry of September 2011 on the koala and demonstrated the intense public interest in the survival of this iconic species. Its subsequent listing for Queensland and NSW under the Commonwealth Environmental Protection and Biodiversity Conservation Act 1999 further raises its profile and obligations for management of koalas and their habitat. It will take considerable effort to manage the Liverpool Plains koala population for the next 50 years in the face of extensive land-use changes from mining, and the attendant threats from road kill, compounded by the new threat of climate change manifesting itself as an increased frequency of heatwaves and more severe droughts. This paper describes the research that underpins these conclusions, identifies some of the research approaches needed, argues for working strategically now, rather than try to patch up matters after the event, and presents a set of guides for environmental plantings. CITATION:Lunney, D, Lemon, J, Crowther, M S, Stalenberg, E, Ross, K and Wheeler, R, 2012. An ecological approach to koala conservation in a mined landscape, in Proceedings Life-of-Mine 2012 , pp 343-352 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By Adrian C. Dorenfeld

The lesser developed countries (LDC's) may be classified into two categories: 1) oil producers, and 2) non-oil producers. The non-oil producing LDC's, as a class, are at present in very difficult financial straits. (1) Since the quadrupling of world market crude oil prices in 1972, an ever greater share of the LDC's export earnings have gone to pay for oil imports, in-stead of national reinvestment. The LDC's inter-national debts--much of it to pay for oil--have soared to record levels, with consequent limits for future credits. (1) Again, this inhibits future national investments, and there does not seem to be an end to the future increase of Organization of Petroleum Exporting Countries (OPEC) prices. Indeed, some of the economic difficulties in some metal markets--particularly the imbalance of production vs. markets for copper, can be traced indirectly to the OPEC cartels' heavy-handed impact on copper producing LDC's which must produce copper at any price to meet their oil bills. (2) Among the major oil importing LDC's are the Philippines and South Korea. 50th nations have substantial cement industries. The South Korean industry is geared for major export markets in the Far East. Both nations have ambitious plans for economic growth in order to accommodate burgeoning populations with ever increasing expectations for high standards of living. These plans had some success, more or less, until the high OPEC oil cartel charges had to be borne. Now, in common with all oil-deficit areas, the Philippines and South Korea are seeking lower cost sources of energy. Both countries have coal deposits. In the case of the Philippines, the reserves are in scattered, relatively small deposits. Most of the coal deposits are faulted, folded and, in general present formidable production problems for limited reserves. Nonetheless production has been on the order of about 70,000 to 150,000 tons per year in the last 30 years. Prior productions (1920-1941) varied between 9,000 Co 150,000 tons per year. (13)

Jan 1, 1978

In situ mining is no longer a "last ditch" approach for recovery of uranium, but a proven and competitive method of exploiting sedimentary deposits. Today, in any feasibility study of uranium properties, the project manager would be prudent to compare the economics of in situ methods with conventional surface and underground techniques. In this comparison of in situ and open-pit mining, John J. Borkert and Carl E. Gerity of Occidental Minerals Corp., evaluated a group of hypothetical uranium deposits using the three most sensitive depositional characteristics of depth, size, and grade. Their conclusion: in situ is generally the better method to maximize total net profits and return on investment. At uranium values of $40 per pound, their analysis found open-pit mining to he unprofitable, generally, when stripping ratios were greater than 30:1, the deposit grade-thickness (GT) was 0.5 or less, or the ratio of depth to GT was greater than 200.

Jan 10, 1978

By James A. Brown, Marius Botha, Christopher A. Fleming

"The technical and economic feasibility or re-processing hundreds of millions of tons of tailings in a number of historic gold tailings dams in the Witwatersrand area of South Africa is being investigated. The objective is to recover uranium and residual gold from the tailings, as well as to oxidize the sulphides to eliminate long term environmental liabilities associated with acid mine drainage. The tailings from the re-processing plant will be re-deposited in a new area far from urbanization, allowing for the rehabilitation of the real estate currently occupied by these historic tailings.The first step in the process involves a mild-regrind and mild acid leach of the tailings (pH 2.5 to 3.0) to dissolve up to 40% of the uranium. This uranium is recovered directly from the pulp by resin in pulp (RIP) with a strong base resin. The RIP tails are then treated by flotation to recover a rougher pyrite concentrate, and flotation tailings that are discarded. The rougher concentrate is cleaned to produce a final pyrite concentrate and cleaner scavenger tailings, and the pyrite concentrate is oxidized in an autoclave to leach uranium and generate acid. The autoclave discharge is combined with the cleaner scavenger tails, and the acid and ferric ions generated in the autoclave are used to leach more uranium and oxidize more sulphide in the cleaner tails. The product from the concentrate leach circuit is processed by resin in pulp for uranium recovery, followed by neutralization, cyanidation and carbon in pulp for gold recovery.The rougher float tails may be further treated to recover gold that was not recovered in flotation, but which had been liberated from the old dumps by natural oxidation of some of the pyrite over many decades. The float tails would be neutralized and treated by cyanidation and CIL to recover this liberated gold.All parts of the flowsheet have been extensively tested in the laboratory, and the critical elements of flotation, pressure oxidation and resin in pulp have been demonstrated in pilot plants. The results of the hydrometallurgical investigations are presented here."

Jan 1, 2010

The small scale alluvial gold mining industry in Papua New Guinea (PNG) is c.irrently the only form of small scale mining carried out in this country. It already contributes significantly to the economy with current production estimated at 2 000-2 500kg per year. Until recently, small scale alluvial gold mining has been confined to simple panning and sluicing of high grade alluvial and colluvial deposits. Traditionally the small scale miner in PNG has only worked gravels with gold grades in excess of 500mg/m3. Grades of this order are required to justify the hard physical labour involved ~n hand operated small scale mining methods. .he introduction of higher throughput technologies such as trommels fed by hydraulic excavators has the effect of altering what constitutes an economically viable deposit. Mechanised techniques allow for the consideration of grades of almost half that level. The potential and opportunities for utilising this type of small scale mechanised mining in PNG are enormous with large areas of ground with gold grades running in excess of 250mg/m3 and often up to 2000mg/m3 throughout the country. An assessment of the current operating economics of this technology in the PNG context is the principal objective of this paper. Small to medium scale mechanised mining can potentially contribute significantly to the PNG economy particularly as it lies within the react-, of many PNG businessmen. Its potential is currently somewhat limited by a general lack of infrastructure and is also constrained by socio-political factors.

Jan 1, 1991

By C M. Standen

The SAG mill at Rasp Mine has undergone a number of liner design modifications since commissioning in 2012, making liner wear and failure difficult to predict from historical data. During 2017, several instances of liner failure or near failure were experienced resulting in unplanned downtime for emergency relines or to patch liners in the lead up to a planned shutdown. The strategy for relining mills is often to minimise the frequency of relines (and subsequent shutdown costs) by extending liner life, achieved through design modifications. However, it was observed that as the Rasp SAG mill liners wear, mill performance declined with power draw increasing and throughput declining. Opportunity and inefficiency costs start to erode the revenue per additional tonne milled for a given set of liners, and in turn the benefit of delaying relines. As such, optimising the frequency of relines becomes a trade-off between reline costs and opportunity/inefficiency costs in delaying relines. The aim of this paper is to demonstrate a frame work for analysing costs using a marginal economic analysis with the assumption that the Law of Diminishing Returns can be applied to the life of mill liners. The SAG mill operating variables can be modelled to determine their impact on costs and an optimal reline point can be defined where the total costs are minimised. This prevents unexpected failures due to accelerated wear by providing justification to reline earlier and thereby allowing efforts to be focused on sustaining milling performance.CITATION:Standen, C M, 2018. An economic approach to optimising mill reline frequency – a case study of SAG mill relines at Rasp mine, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 197–206 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By Don K. Smith

The northern zone of the Indus Basin comprises a vast area of essentially level land in West Pakistan which is irrigated by means of a complex system of canals that distribute more water to more land than any other irrigation system in the world. In spite of the development of this extensive irrigation system, production of food and fiber has not met the requirements of the country. The major reasons that crop production has not reached anticipated levels are the lack of adequate irrigation supplies and effective subsurface drainage. As a result, yields per acre are among the lowest in the world for areas where irrigation is practiced, and many thousands of acres of valuable crop land have been removed from production or are seriously affected by salinity and waterlogging. To rectify the problems of irrigation supply and drainage the Government of Pakistan has undertaken a program of Salinity Control and Reclamation which is being administered by the Water and Power Development Authority. The Authority retained Tipton and Kalmbach, Inc. , of Denver,, Colorado as Engineers for the program in the northern zone of the Indus Basin. -This program consists of the construction of about 30, 000 irrigation wells to provide drainage for waterlogged lands and full irrigation supplies, including leaching requirements, for; all cultivated lands. The program will ultimately ensure the productivity of 20 million acres and will involve an annual pumpage from ground water storage of nearly 40 million acre-feet of water. The value of the crops produced when the program is in full operation will be 4 to 6 times the value of the crops that could be produced without the benefits of this program.

Jan 1, 1967

By I. Bock

Selective Blast Mining (SBM) makes use of milli-second sequential blasting technology to separate the valuable reef material from waste rock in the blasting operation at stope faces in the mining of tabular ore bodies such as exist in the gold and platinum mines in South Africa. The waste rock is cast blast to the back of the stoping area, and the reef material is fractured and deposited close to the stope face. Only the reef material is transported to the surface. A simplified economic model is presented to evaluate the economic benefits of SBM. Although premature, in that adequate experimental demonstration of the validity of the model has not yet been possible, the model is presented since it indicates substantial benefits in the case of narrow reef gold mines. It is suggested that many marginal mines should seriously consider SBM. Benefits can also be realised in platinum mines, but a lot more experimental work is necessary to establish cost parameters more reliably. Some practical experience in the use of SBM in the mining of the UG2 reef is presented.

Jan 1, 1998

By G. P. A. Howe

"A computer model of the rutile, ilmenite and zircon industry was developed jointly by Associated Minerals Consolidated and Consolidated Gold Fields for exploring marketing strategies and making predictions over a ten-year period. The industry is described briefly and the reasons for modelling it and choosing a deterministic approach explained. The economic structure of the model and its level of complexity are discussed. The necessity and techniques for convenient input and clear output, the team composition and the method of work are discussed.The reasons for the choice of FORTRAN, large computers, remote batch terminals and the vital importance of fast turn-round are discussed.Costs in staff time and computing are given, with an assessment of the reasons for the success of the model. The model is used on a regular basis to aid management decisions."

Jan 1, 2014

By Gerry Norton

The purpose of this paper is to make the most complete assessment of coal cleaning methods, both process and equipment related to modern-day production and environmental requirements. In order to achieve this primary objective, a number of interdependent aspects of coal cleaning technology require evaluation and analysis. 1.0 CLASSIFICATION OF SEPARATION PROCESSES Processes and cleaning equipment can be categorized according to the important parameters of 1) mechanics of separation, 2) size range application, 3) range or variance in accuracy of separation related to 2) above, and 4) feed-size ratio affecting 3) above.

Jan 1, 1977