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By L. S. Jeffrey

Estimates for South Africa?s coal recoverable reserves made in 1999range from nine to 59 billion tons; latest estimates by the Minerals Bureau suggest that 33 billion tons is a more likely figure. As much as 70% of that coal is located in the Waterberg, Witbank, and Highveld coalfields, as well as lesser amounts in the Ermelo, Free State and Springbok Flats coalfields. However, the Witbank and Highveld coalfields are approaching exhaustion (estimated 9 billion tons of recoverable coal remaining in each), while the coal quality or mining conditions in the Waterberg, Free State and Springbok Flats coalfields are significant barriers to immediate, conventional exploitation. New extraction technologies, technologies exploiting the energy content of the coal in situ, as well as suitable uses and markets for low-grade, high-ash coal are required before the country can utilize its admittedly vast coal resources. Major challenges for exploiting some Limpopo province coalfields are severe water shortages, insufficiently developed infrastructure, fragile environments and poor roof conditions due to the depth and complex geology. In the Central Basin (Witbank, Highveld and Ermelo coalfields) technical innovations for thin seam extraction, economic mining of both pillar coal and intrusion-fragmented resource blocks and the utilization of lower-grade coals are required. The success of the fluidized bed combustion technology is necessary to utilize the low-grade coals of the Free State and Molteno coalfields, while environmental exemption for past problems, together with strategies for mining small, disjointed thin-seam resource blocks, is required in KwaZulu-Natal. Clean coal technologies, coal cost and quality, environmental considerations, sustainable development, the growth of the South African economy and Government?s regulation of the electricity industry are the main challenges to the continued use of coal as South Africa?s primary energy source.

Jan 1, 2005

By F. Ziaie

Line electrical resistivity method using physically infinite distance between current line electrodes is proposed to determine the location of mine workings. In this method at least three line electrodes are used. One of the current electrodes is used as a sinkhole electrode while the other two are used for different activiations of line electrodes when the survey area is between one of the line electrodes and outside the other one. The resistivity profiles perpendicular to the current line electrodes for different activation of electrodes is plotted versus the distance of the midpoint of the measuring potential electrodes. The anomaly due to presence of any locally lateral resistivity variation (e.g. mining cavity) will represent itself as peak or trough depending on resistivity contrast between the source of the anomaly and surrounding medium. Physical simulation of the proposed model was conducted by using a tank model in the laboratory. The results of experiments appear to be consistent with the theoretical model. Experiments for different depths and different spacial locations of the simulated cavities appeared to be successful for locating the depth and size of the cavity.

Jan 1, 1989

By V. Prodanovic, M. Militzer

Production of advanced linepipe steels with strength levels of 685MPa (100ksi) and higher requires excellent control of runout table cooling to produce the desired final fine-grained microstructures, which may include acicular ferrite. Cooling is exerted on the runout table by applying water jets onto the hot surface of the strip and heat is removed from the steel by forced convective boiling. The associated boiling mechanisms are complex and include film, transition and nucleate boiling. A pilot-scale runout table test rig has been built to systematically study boiling heat transfer from a moving steel plate by employing industrial scale headers. Experiments were conducted using test plates moving at speeds between 0.3 m/s and 1.4 m/s. The plates were cooled down from 850°C to temperatures below saturation by a single water jet supplied through an industrial size circular nozzle. Based on these experiments heat fluxes were determined and further used to develop improved runout table cooling models.

Jan 1, 2005

By C De-Vitry

"The large Yandi channel iron deposit (CID) is located in the north-west of Western Australia and is currently mined via open pit methods. Drilling at Yandi is widely spaced and current estimates are mostly linear averages of the surrounding local samples. Linear estimates such as ordinary kriging (OK) based on block sizes that are significantly smaller than the dimensions of the drilling grid are less variable than the unknown reality (Armstrong and Champigny, 1989).Conditional simulation (CS) provides a series of plausible realisations that represent the actual grade variability at a small scale (eg 1 m + 1 m + 1 m). These simulations are very useful for a number of purposes, eg: optimising grade control, stockpiling and blending selection of optimal drill hole spacing assessing resource risk on contained tonnage and metal.At Yandi the major constituents of the ore (Fe, P2O5, SiO2, Al2O3 and LOI) are correlated to varying degrees. Independent CS of each assay variable will not reproduce these correlations. Reproducing the correlations (and the shape of scatterplots) is important if the simulations are used for the abovementioned purposes. This paper examines and compares various methods of CS that aim to reproduce the correlations between the assay variables.The CS methods evaluated in this paper are conditional co-simulation (CCS) using the linear model of co-regionalisation and two other, alternative multivariate simulation methods, which use min/max autocorrelation factors (MAF) or the stepwise conditional transform (SCT) to de-correlate assay variables before performing independent CS. It was found that CCS best reproduced the characteristics (histograms, variogram, scatterplots, etc) of the declustered drill hole data (Figure 1). Whilst simulation using MAF generally produced acceptable results, the method did not adequately reproduce the variance of the assay variables. The univariate statistics, histograms and experimental variograms were acceptable for simulations generated from the SCT. Bivariate statistics, cross-variograms and scatterplot reproduction for the SCT were unacceptable. The latter method produced inferior results because there were insufficient samples to obtain a reliable transform of the third assay variable in the transformation sequence.None of the abovementioned simulation methods provides good reproduction of all the scatterplots. This is due to the presence of clay pods, which cause some scatterplots to display two trends. These clay pods contain higher percentages of SiO2 and Al2O3 than the surrounding CID. The clay pods are generally smaller than the drill-grid dimensions. Thus their locations are typically unknown and they cannot be defined by manual interpretation, eg via wireframes. The locations of the clay pods were simulated via indicator CS. CCS was then performed separately for the clay pods and the CID. This significantly improved the reproduction of the correlation coefficients, the scatterplots and visually the simulation was more geologically realistic. Simulating the location of clay pods followed by CCS of assay variables is the recommended approach for simulation at the Yandi CID.CITATION:De-Vitry, C, 2013. Simulation of correlated assay variables - a case study from the Yandi Channel iron deposit, in Proceedings Iron Ore 2013, pp 137-148 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 12, 2013

By L. H. Michaud

"Albian Sands Energy (ASE), an oil sands surface mining and extraction operation, is currently undergoing start-up and is scheduled to ramp-up to full production by mid-2003. Startup includes the selection and implementation of over 75 IT systems or computer applications which include: engineering applications; systems required to control mining activities, maintenance, the processing plant and utilities; and also systems required to run the company, such as human resources, finances and inventory/ warehousing.This paper outlines the processes used for the selection, implementation and integration of these systems in order to optimize the use of information and to meet the technical, business and IT requirements of the company. The first step in ASE’s approach to identifying system requirements is the development of a business activity model, outlining all tasks involved in running the operations. The computer applications required to accomplish each task are then identified by having the IT team work closely with each technical and business unit. Historically, at some companies, the selection of systems has been led by the IT team or by consultants, with little input from the technical or business units. Typically, this results in products that do not meet the company’s expectations. To ensure a more positive outcome, ASE believes that it is imperative that the company’s technical and business people be closely involved in the selection process.Integration of the IT systems is also key, including linking all applications through a data warehouse and EDMS. Over 120 required integrations have been identified. This ensures the storage of all data in only one location, data security, and easy data and document retrieval for all requirements throughout the company"

Jan 1, 2003

By Wendy L. Mathieson

The Bonneville Power Administration (BPA) will build about 500 miles of new 500-kV transmission lines in the next 5 years. Many new lattice towers will be built in remote locations or in environmentally sensitive areas. Therefore, micropile foundations were designed that could be installed in remote areas, in variable subsurface conditions, and in a manner that would reduce excavation volumes and potential erosion concerns. Typical lattice tower foundation axial loads range between 75 and 1,500 kips (300 to 6,700 kilonewtons [kN]) per leg, with uplift loads being slightly less than compressive loads. Lateral loads range from 5 to 320 kips (20 to 1,400 kN) per leg. Full-scale axial and lateral load tests were conducted in geologically representative soil units during the micropile design for the 9-mile-long (14-kilometer [km]), Kangley-Echo Lake transmission line that extends through a protected watershed east of Seattle, Washington. Micropile foundations for single and double circuit suspension and dead end towers were designed using these load test data.

Jan 1, 2004

By Tracy Brettmann

Equipment ? Hollow Stem Auger ? Drill Bits ? Leads/Torque Arm ? Hydraulic Gearbox ? Hydraulic Power Unit ? Grout Pump ? Crawler Crane

Jan 1, 2004

By D. M. Morrison

"The most important factor in Canadian mining is not the operating cost of current projects but the availability of capital for future projects. The future of mining at depth will be producing ore from the top of the orebody working downward with very effective, tightly controlled mining methods, i.e. either selective mining or bulk mining with well controlled dilution and fragmentation. The key characteristics of future mines will be smaller access excavations, more effective ground support, very precise blasting techniques and more efficient and reliable materials handling systems. Equipment will be smaller and designed for high efficiency and low maintenance, reducing both the capital and operating cost. This means there will be fewer scoops, more continuous mucking machines and conveyor belts, both lateral and vertical.Orepass failures have become accepted and the resultant redevelopment and retramming has become common. The capital investment in so-called permanent ore passes and crusher stations becomes questionable, particularly when crushers are only necessary for less than 10% of the ore going through the system. The best way to solve the chronic instability of ore passes is, as with all of the stability problems at depth, by reducing the excavation size rather than increasing ground support. Smaller access drifts would reduce the capital cost and increase the rate of development as well as reduce the amount of waste to be handled, reducing the ground support and the ventilation requirements. Large drifts and ore passes are essential only for the equipment needed to handle large pieces of ore and the productivity of scoops is very expensive when the requirements for ventilation and large access drifts are taken into account. The key issue is the fragmentation generated by primary blasting.The future of mining in Canada will depend on simple and robust technology geared to the environment in which it will have to operate. Its survival will depend on some-thing much more fundamental and difficult to accomplish than a technological advance — it will require a dramatic change in the way the mining process is managed, how work is organized, how effort is rewarded and how costs are measured — a complete change in mind-set."

Jan 1, 1996

By O. Ditsele

Coal plays an important role in the energy needs of the World. Given its wide abundance and low cost, coal use is bound to increase with the growing energy demand. Despite its importance, there are growing concerns over coal?s environmental burdens, especially its contribution to greenhouse gas emissions. To ensure sustainable extraction and use of coal, opportunities for minimizing potential impacts from coal have to be identified and exploited. Whilst extensive work has been done on life cycle assessment of coal use, especially in electricity generation which uses the bulk of coal produced, there has been limited work focusing specifically on coal mining. This study aims to estimate the cradle-to-gate life cycle climate change impacts of coal from a surface coal mine in the United States. The study employs general principles of ISO standards for LCA.

Jan 1, 2010

Ceremonies for the induction of four mining industry pioneers into the National Mining Hall of Fame will be held Saturday, Sept. 13, 2008 at the Charles F. Barber Pavilion of the Museum Convention Center in Leadville, CO. This will be the 21st Annual National Mining Museum and Induction Banquet. The four inductees are Lew Eklund, 76, Carrie Jane Billings Everson (1843-1914), ?Colonel? William C. Greene (1851-1911) and Arthur L. Hawkesworth (1860-1905). Lew Eklund founded Eklund Drilling that is now based in Elko, NV. He invented many designs that play a major role in today?s mining industry. His Cyclo Blower and various sampling devices he designed helped to revolutionize gold deposit exploration by allowing mining companies to effectively sample microscopic gold. Carrie Jane Billings Everson discovered and proved a method for bulk oil flotation concentration of mineral ores, the precursor to modern froth flotation methods of minerals concentration. She patented her process in 1886. In the early 1890s, coworkers built and operated demonstration plants incorporating her bulk oil flotation process. ?Colonel? William C. Greene was responsible for the development of the great copper mining properties of Cananea, Mexico. In seven years, he went from ragged cattleman and adventurer to the greatest captain of industry the borderlands have ever seen. Arthur L. Hawkesworth was a master mechanic for Anaconda Copper. He invented the detachable drill bit. His invention generated tremendous savings for the mining industry in time, in dollars and in safer operating conditions underground. His bit?s long lasting contribution to improved mine economics is immeasurable. The 21st Annual National Mining Museum and Induction Banquet will begin with an open house and reception at 5:30 p.m. followed by the dinner and program at 7 p.m. The inductions will bring to 201 the number of mining ?greats? whose engraved photographs and biographical sketches are installed in the National Mining Hall of Fame.

Jan 1, 2008

By D. R. Tesarik

As part of its research program to investigate ways of improving resource recovery and reducing subsidence, researchers from the U.S. Bureau of Mines placed instruments in the B-North ore body of the Cannon Mine, Wenatchee, WA, to monitor cemented backfill and rock deformation during mining. The vibrating-wire gauges proved to be reliable and versatile, and approximately half of the instruments are providing data after 2 years of use. A two-dimensional, finite-element model was used to analyze the Cannon Mine's multilevel bench cut-and-fill mining method and predict rock and backfill displacements. The model accurately predicted rock displacements, but the predicted and measured displacements in cemented backfill had a correlation coefficient near zero, indicating that the model should only be used to predict rock displacements and not backfill displacements. A finite-difference model was also used to evaluate the stability of a cemented backfill pillar. Results can be used to conservatively predict backfill stresses, but on-site observation of pillar failures coupled with in situ measurements are needed to make more accurate predictions. An ongoing evaluation of the mining system has indicated that filling the primary stopes tight to the back with cemented backfill allowed these pillars to carry overburden loads soon after the cemented backfill was placed.

Jan 1, 2010

By J. I. Mathis

"The failure that was utilized for developing this model was a double bench-scale failure, approximately 20 m in height, in the Misery pit at BHP Billiton’s EKATI mine site. The bench that failed was excavated in biotite schist. Due to previous problems with bench-scale toppling failures, this bench was excavated with a 70° inclined, 30 m deep preshear. Upon exposure, the wall was very clean with half-barrels commonly observed from the pre-shear operation.In August 2003, a bench failure of about 1000 t occurred in this pre-sheared biotite schist (Fig. 1). Upon examination it was noted that the foliation that paralleled and dipped at 70° into the face when excavated was approximately horizontal at the top of the failure (Fig. 2). While the failure mode itself appears complex, the failure was apparently driven by three factors:• a low-angle, low-frictional strength fault or discontinuity at the base of the failure area;• water either contributed meteorically from precipitation and/or from permafrost melt; and• foliation planes providing a viable toppling geometry once toe block motion began to occur.The above details are illustrated in Figure 3.After considerable thought and analysis, a model was postulated for the failure.It is thought that the entire failure had been triggered by displacement of a toe block (Fig. 4). This toe block is bounded on the back by foliation, the bottom by a low-angle, lowstrength fault, and the front by the bench face. Water pressures behind the bench face developed forces on the block as can be seen in Figure 5. These forces were sufficient to induce block motion. As can be seen in the relative shear strength diagram in Figure 6, only a small amount of water is necessary in the face to initiate block displacement. Note that in this figure, a simplistic piezometric pressure distribution was assumed."

Jan 1, 2004

By J. Martinovic

The large proportion of gangue minerals present in platinum bearing ores in South Africa provides challenges to the flotation and downstream processes. In order to take effective measures to reduce their recovery in flotation, an understanding of the mechanisms and factors influencing their behaviour is needed. Typical gangue minerals are pyroxene, feldspar, quartz, chromite and talc. Of these, talc is a naturally hydrophobic mineral and although it is present in relatively small quantities, it has a disproportionate effect as it has a strong froth stabilizing effect, increasing the recovery of other gangue minerals by entrainment. Talc recovery is effectively reduced with the addition of polymeric depressants. Although the other gangue minerals are assumed to be hydrophilic and their recovery by entrainment is expected to follow the water recovery, there is some evidence that they may be activated by the typical reagent suites used. Reagents such as copper sulphate, added as an activator, and collectors are used to selectively induce hydrophobicity on the sulphides. It has been shown that some of these gangue minerals can be activated. This research work investigates whether inadvertent copper activation is mineral specific and evaluates the mechanisms and factors affecting the reversal of activation with the addition of the depressants using electrokinetic measurements, adsorption and microflotation tests. Results are presented that show that the selected minerals do respond differently and that the reversal of activation is dependent on mineral type, depressant type, dosage and ionic strength of the electrolyte.

Jan 1, 2005

By F. L. Clerc

THE lead and zinc region of SW. Missouri is interesting, not only by reason of the value of its output, which ranges in the neighborhood of ten million dollars a year, but even more because of the facilities which it offers for the study of certain forms of ore-deposits, of which the loci and genesis are somewhat obscure. Although the mineral species found in the region are few and of common occurrence, crystallization has taken place on a generous scale, and unusual forms abound in many combinations, presenting examples of pseudomorphism, paragenesis, metasomatic replacement and the action of mineral-depositing and mineral-dissolving waters. For the mineralogist, lithologist, and specialist in certain lines of metamorphism, it has peculiar attractions, while the systematic geologist will perhaps find its chief claim to attention in the simplified problem it presents, in the study of ore-deposits. In addition to the phenomena above enumerated, it presents instances of well-developed comb-structure in the ores, fissures and faults, and slickensides-features usually associated with extensive movements in the earth's crust, and believed by some authorities to prove the deep-seated origin of the ores. In connection with these occurrences, the absence of all igneous rocks from this region is noteworthy and significant. For that reason, the simplified case presented by the Joplin region, from which these rocks have been eliminated as a factor, is specially valuable. Having had unusual opportunities to watch the development of this district, I have been deeply interested in the bearing of the revelations of the Joplin mines upon questions of universal importance to the science of ore-deposits ; and it was to my great regret that the project of a meeting of the American Institute of Mining Engineers at Joplin, proposed in 1892, was

Mar 1, 1907

Aurum Reef Resources is a provincially owned unlisted public company which holds a number of prospecting licences over Otago hard rock historically active minesites. The Bullendale Licence 31 1845 was applied for in 1985, granted 1991, including a DoC special condition allowing re-opening of the historic workings. The underground workings were commenced in 1862 and up to the mine's closure in 1906 some 40 000 ounces were produced at an average grade of 15.5 g Au/t. The purpose of the summer 1991 work programme was to enter the workings in an attempt to observe and sample the mullock between the lodes operated by the early miners. This objective was achieved on the third attempt. Samples were taken and subsequently a contract geologist resampled the workings and prepared a report indicating the Bullendale lode zone to be generally mineralised. Mullock interlode and schist foot-wall consistently returned assays over 0.5 g/t.

Jan 1, 1992

By Xie Qiang

It is known that the stress state inside rock discs under Brazilian tests is neither simple compression nor tension, but a complex combination of both stress types, as well as for a beam subjected to bending, where compressive and tensile stresses are separated by the neutral axis. In this study, AE generation was obtained on pure white marbles from south Portugal that were submitted to both Brazilian and bending tests. Main questions to be answered were: (1) Does Kaiser effect exist in tests which create complex distributions of tension and compression? (2) Are there any meaningful differences in AE behavior of marble under Brazilian and bending tests?

May 1, 2009

Draft tube circulators are now widely used instead of Pachucas for suspension of slurries in large tall tanks.Precipitators in the alumina industry are an example.Draft tube/tank diameter ratio is critical. Two independent criteria are given for optimum ratio. The hydraulic and energy relationships are defined. These require an impeller of very high specific speed. For a stable and efficient system the impeller should have aerofoil blades with a pitch angle which decreases from hub to tip.The draft tube must be matched to the impeller with inlet baffles above the impeller and flow control vanes below it. Tip recirculation must be suppressed. The tank itself should have a filleted flat bottom.Such a system exhibits the behaviour of axial flow devices with the characteristic undesirable behaviour at low flow.Installed and operating power requirements depend critically on hydraulic design and to a lesser extent on speed reducer efficiency.The problems of re-suspension have been overcome by a patented slot system which also improves behaviour at low flow to permit a more economic design. A number of other practical operating considerations are also discussed.

Jan 1, 1982

By A Priatna, H Rumbino, T Casten

This paper discusses the progress of the Deep Mill Level Zone (DMLZ) mine from the pre-feasibility study completed in 2005, through commencement of development access in 2008, completion of the feasibility in 2010 and cave initiation in late 2015. This fourth lift of caving in the East Ertsberg Skarn System (EESS) is located 500 m below the currently producing Deep Ore Zone (DOZ) mine and represents approximately half a billion tonnes of ore and around 1900 planned drawpoints, scheduled to be mined at a peak of 80 000 t/d.The paper reviews the mine design, access requirements, planned footprint sequence and major fixed facility installations such as ventilation, oreflow and shops. A discussion of the preproduction development and construction activities and some of the critical technical challenges overcome during this time frame are addressed, as well as the cave initiation process undertaken in late 2015 and the ramp-up of production and progression of caving.CITATION:Casten, T, Priatna, A and Rumbino, H, 2016. Deep Mill Level Zone – from feasibility to production, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 635–644 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

Results of laboratory studies on the flotation of marmatite (zinc sulphide) with new reagents, which were developed to avoid the use of copper sulphate, are presented.Episulphides were chosen as the basis for the reagents because of their reported special chemical affinity for zinc and cadmium. Attempts were made to solubilize and introduce functional groups to episulphides with organic and inorganic acids, ammonia, phenol, aniline, diethylamine, and pyridine. As a class of reagents, the episulphide-amine combination was generally found effective in zinc sulphide flotation to a greater or lesser degree. Best results were obtained with ethylene sulphide-aniline combination. Although anilino-ethyl mercaptan is the reported reaction product of aniline and ethylene sulphide, it was concluded that the effective zinc sulphide flotation with ethylene sulphide-aniline combination is not entirely due to the formation of the mercaptan.The economics of the possible usage of ethylene sulphide-aniline reagent are discussed.

Jan 1, 1974

By M. Javier

"The impact of mine closure is perceived through a veil of compliance to human laws and regulations rather than the laws and equilibrium of nature. This perception motivates present research. Understanding the causes and effects of mine closure defines levels of responsibility. This understanding evolves from mine closure's legacy. Mine closure is characterized in perpetuity by three aspects: Future liabilities; level of technologies for extraction and, usage of mineral resources. These aspects must be updated to a rationally appropriate level. This paper will address the following questions: Will the minerals remaining in the process of mine closure ever be recovered? Will the mine closure inhibit the availability of minerals for the next generation? How many mines are designed to perform a successful mine closure? Do we close the mines or do we close nature? Is it responsible to continue mine closures as we do them today? Is mine closure a complement of mine operations or a contradiction of mining? Do we need to perform mine closures, yet? This paper reviews mine closure practices and principles with the level of responsibility to nature and for the next generation.PREFACE The planet has irreversible issues to deal with regarding the depletion of mineral resources and contamination occurring from human activities. The population increased exponentially to more than seven billion, this high population with its lifestyles, demands a higher supply of minerals. In spite of these conditions, mining is a vital industry to keep ""civilization"" in society. This is evidenced by what we see around us, in that everything ""made"" in society is directly or indirectly due to mining. Hence, mining cannot be avoided or ignored. Society misunderstands the importance of mining in relation to other activities. At this time, mining is fragmented and economically oriented to supply cheap minerals to a market with peculiar characteristics regarding products that could be designed for recycling and stimulate nature’s equilibrium. These issues add important “variable factors” to the equation, when they are considered as parameters for the next generation. It also raises many questions regarding principles and attitudes about morals and ethics exercised in all anthropogenic activities. The industry's practices have many flourishing paradigms which are subject to a variety of criticisms and observations. Some of these observations will be described in this paper. It is important to clarify in advance a ""normal disclaimer"" about the ""apparent contradiction"" that could take place in the writer's comprehension when we abruptly ""jump to conclusions"". We must remember that we are profiling the future in an arena that demands a better understanding of solutions to problems created by actual mining."

Jan 1, 2015