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By R. G. Gillies

The pipeline transport of paste, backfill or thickened tailings slurries is an important component of the tailings disposal process in many mines around the world. These mixtures contain significant fractions of fine (clay) and coarse (sand) particles, causing them to exhibit non-Newtonian flow behaviour and high frictional pressure gradients. There is often economic incentive to operate these pipelines in the laminar flow regime. Irrefutable evidence has shown that coarse particle settling can occur during the laminar flow of these slurries even when static settling tests show no indication of such behaviour. Previously, a ?rule-of-thumb? minimum frictional pressure gradient of ~1.5 to 2 kPa/m was suggested to ensure effective sand transport, based on the results of tests conducted using viscous Newtonian oils. In this paper, we examine the results of laminar flow tests of non-Newtonian, coarse-particle laden slurries conducted with pipeline loops of 50, 100, 150 and 250 mm in diameter. The results indicate that the ratio of the mean wall shear stress to the mean surficial particle stress is a better indicator of laminar flow settling tendency than frictional pressure gradient.

Jan 1, 2007

By William E. Ford, Edward Salisbury Dana

Secondary Twinning. - When there is reason to believe that the twinning has been produced subsequently to the original formation of the crystal, or crystalline mass, as, for example, by pressure, it is said to be secondary. Thus the calcite grains of a crystalline limestone often show such secondary twinning lamella?. The same are occasionally observed (Ilc, 001) in pyroxene crystals. Further, the polysynthetic twinning of the triclinic feldspars is often secondary in origin. This subject is further discussed on a later page, where it is also explained that in certain cases twinning may be produced artificially in a crystal individual - e.g., in calcite (see Art. 282).

Jan 1, 1922

By Arash Khosravifar

The seismic design of extended pile shafts for the combined effects of dynamic shaking and liquefaction-induced lateral spreading is investigated using nonlinear dynamic finite element analyses (NDA). Results of NDA parameter studies are used to illustrate how inertia and lateral spreading loads combine during shaking. The NDA results are used to evaluate equivalent static analysis (ESA) methods. Implications for design practice are discussed.

Jan 1, 2010

By Patrick A. Hamilton

This Bureau of Mines report delineates the coal reserve base of anthracite, bituminous and subbituminous coals, and lignite, by mining method and sulfur content, for coal-bearing States west of the Mississippi River. The parameters used to establish the reserve base definition are the result of a joint agreement by the Federal Bureau of Mines and the U.S. Geological Survey. The reserve base of low-sulfur coal, =10 percent sulfur, is 167,324.5 million tons; medium-sulfur coal, 1.1-3.0 percent sulfur, is 37,531.5 million tons; and high-sulfur coal, >3.0 percent sulfur, is 11,244.1 million tons. The reserve base of coal with an unknown sulfur level is 18,323.0 million tons. The percentages of deep and strippable coal are 56 percent and 44 percent, respectively. The basis for reserve base estimates and analytical data for this report was the Fuels Availability System, a Bureau of Mines data bank containing numerous data tin fossil fuels. Information contained in the system was obtained from publications of the Bureau of Mines, U.S. Geological Survey, State agencies, private publications, and company data.

Jan 1, 1975

By Axel Doelcken

?? Liebherr excavators in standard configuration are generally designed to operate in an ambient temperature range between -12°C and +55°C (10.4 °F and 131°F). ?? To operate effectively and efficiently in very low temperatures special consideration needs to be given to the design ??An inappropriately designed hydraulic system unable to withstand extreme changes in temperatures or varying working conditions will lead to: - premature wear and more frequent replacement of components - increased maintenance & unplanned downtime This will affect productivity & operating costs.

May 1, 2008

By Z. M. Zhang

Fracture grouting is a particular technique which can be used in soils and rocks with low permeability to increase groutability and penetration rates and to solve some special foundation problems by inducing limited and controlled zones of hydrofracture surrounding the injection source. The present paper describes the basic principles of hydrofracture and its application to grouting in deep foundations, and indicates some recognitions about the mechanisms and effects of fracture grouting.

Jan 1, 2010

By A. MacG. Robertson

A cone penetrometer has been used to assess the level of stress existing in hydraulically placed mine backill. The test apparatus was fabricated at the mine and consisted of a steel cone, connector rods and a hydraulic jack. Testing was carried out from a manway passing through the centre of the stope. The cone was pushed horizontally into the fill, both at right angles and parallel to the orientation of the stope walls, and the resistance to penetration was measured. Corrections were made to allow for friction along the rods. In a cohesionless sand, such as mine fill, the point resistance should be directly related to the in situ stress. The stresses in mine backfill are due to o the self weight of the fill o convergence of the footwall and hangingwall of the stope. Silo theory was used to estimate that component of the in situ stress due to the self weight of the fill. The difference between the stress predicted by silo theory and the stress estimated from the cone resistance was assumed to be due to convergence of the stope walls.

Jan 1, 1986

By Jeff R. Reinson

The Diavik Diamond Mine is producing diamonds from two orebodies, the A154 South and A154 North kimberlite pipes, discovered beneath the waters of Lac de Gras. Innovative dike technology with appropriate water collection and treatment systems allowed Diavik to start open pit mining of the ore bodies in 2002. To allow planning, engineering, and implementation of sufficient water handling infrastructure, reasonably accurate estimates of groundwater inflow quality and quantity over the life of mine are required. Prior to mining, a numerical model using the continuum approach was developed for regional and site wide water management. After approximately two years of mining, groundwater inflows to the pit were found to exceed those predicted by the base case hydrogeologic model. The most likely explanation was flow through Dewey?s Fault zone. As this fault was not explicitly accounted for in the model, a detailed hydrogeologic investigation was conducted to evaluate its geometry and hydraulic properties. A multi-disciplined approach was used and involved core logging, fluid logging, geophysical logging, packer testing, a pumping test, and water quality sample collection. The results of the field investigation were used to update the conceptual and numerical models and to develop a Discrete Fracture Network (DFN) model to address small scale problems such as flow into future underground drifts. The updated numerical hydrogeologic models predict that up to 70 per cent of the groundwater inflow to the A154 N/S open pit is through the relatively narrow fractured rock zone associated with Dewey?s Fault. Consistent with the continuum model, the DFN model predicts that inflow to a drift excavated in Dewey?s Fault will be approximately 10 times the inflow to a drift excavated in competent rock. The DFN model provides a better understanding of the distribution of these inflows on a local scale over the length of the drift.

May 1, 2006

By Ch. Schroeder, F. Collin, R. Charlier, Y. J. Cui

The paper proposes two numerical models ot the mechanical behaviour of chalk. First, an elasto-plastic constitutive law reproduces the different plastic mechanisms of the chalk and the influence of pore fluids by introducing the concept of suction. Secondly, a model able to reproduce time dependence behaviour. Eventually, the paper gives a simulation of an academic reservoir during depletion and waterflooding phase. Der Artikel stellt zwei numerische Modelle des mechanischen Verhaltens der Kreide vor. Das erste ist ein elasto-plastisches Modell, das verschiedene plastische Mechanismen der Kreide und den Einfluss von Porenflüssigkeit, unter dem Begriff der Suktion, reproduziert. Das zweite Modell berücksichtigt darüberhinaus das zeitabhängige Verhalten. Schliesslich zeigt die Veröffentlichung eine Simulation einer theoretischen Lagerstätte während der Entleerung und der Wasserinjektion. L'article propose deux modèles numériques du comportement mécanique de la craie. Le premier est une loi élasto-plastique qui reproduit les différents mécanismes plastiques de la craie et l'influence du fluide interstitiel par l'introduction de la notion de succion. Le second est un modèle prenant en compte les effets différés. Enfin, l'article présente une simulation d'un réservoir académique durant les phases de déplétion et d'injection d'eau.

Jan 1, 2003

By Floyd C. Bossard

In underground mining operations, the over- riding issue has to be protection of worker health and safety. The employees underground, making a living in a dangerous occupation, know these are major issues. These men bargain their lives and health on the presumption that the operating management knows its business, and they, the underground employees, can pursue their occupation with the assurance that management has provided a safe and healthy ambient underground environment. When management assumes the mantle of protection of underground workers, it has to be positive that qualified engineers have designed the project, and that capable operating personnel are in charge and always available. Those persons with these responsibilities must be knowledgeable in the engineering and occupational health aspects of sine ventilation. The ultimate function of a mine ventilation system is to provide a comfortable, healthy and safe ambient environment for the underground workers. The attainment of these objectives has been complicated with the increased application of electrical equipment and diesel-powered mechanized mining equipment underground (discharging toxic diesel emissions); increased production rates with the attendant increased production of airborne dust; and mine development in increasingly hostile mineral formations containing combustible strata gases, radon gas emissions, along with high heat and humidity. In general, the modern mechanization of present mining operations has resulted in a sore complex set of problems for the engineer planning the underground ambient environment.

Jan 1, 1983

By C A. Heinrich, J L. Walshe, V J. Wall

The Porgera Gold Mine, located in the highlands of Papua New Guinea, has produced over 5 million ounces of Au, since its opening in late 1990. The deposit is located within Upper Cretaceous Papuan Platform sediments approximately 25 km south of the Lagaip Fault, and is spatially and temporally associated with the 6 Ma alkaline Porgera Intrusive Complex.

Jan 1, 1995

By Dyson N. F

Mixed cobalt-nickel sulphides precipitated from ammoniacal process liquors derived from nickel sulphide concentrates, mattes, and reduced nickeliferous laterites have been characterized.The mixed sulphides are prone to oxidation on standing and are rapidly leached under relatively mild conditions. The kinetics of the leaching reactions are controlled principally by temperature and oxygen partial pressure. Although the samples have different CO:Ni ratios and have undergone varying degrees of oxidation, there is little difference in their leaching behaviour. The results suggest that a single plant would be able to process mixed sulphides of varying composition. Any copper and zinc present in the mixed sulphides as impurities also go into solution and must be removed prior to recovery of the cobalt and nickel in metallic form.

Jan 1, 1981

Probably no other country or coutinent has so many rich deposits of various different minerals as Australia. Long ago in the days of my boyhood in the old land the marvellous discoveries of high percentage copper at Burra Burra, Peak Downs, Yudanamutana, and other mines, was one of the principal themes of conversation in mining circles whilst the specimens of malachite, azurite, etc, brought home by returning miners were the admiration of my boyish eyes.Later on the WalIaroo and Moonta mines still further helped to heighten the reputation of Australia as a copper-producing country. During the 21 years that the writer has been resident in the Australian colonies, other mineral deposits have sprung into prominence, and with a Mount Bischoff for tin, a Broken Hill for silver and lead, and a Mount Morgan for gold, Australia can now boast that it has had within its borders the leading mines of the world, in four different minerals, and still at least maintains that pre-eminence in gold, silver and tin. To the miner from the old land, Australian mining is at first a revelation and a wonder. In very many instances he looks in vain for the regular strike and dip of the veins he has been accustomed to'Smooth hanging and foot alls are often wanting. 'Huge irregular deposits, like those mentioned above, viz., Burra Burra, Mount Bischoff, Broken Hill, and Mount Morgan, are mysteries that will take time to fathom-if, indeed, they are ever thoroughly understood and in many a smaller deposit there is much to interest alike the professor in the college and the miner in the mine.

By Vedala Sastry

Longwall mining for coal extraction in deeper deposits is gaining momentum in India, due to the increasing stripping ratios and depletion of shallow deposits amenable for surface mining. In longwall mining, presence of multiple seams with varying interburden thickness is a major problem especially while planning for over-mining. An investigation program was taken up to analyze the effect of the presence of goaf and virgin coal blocks in already developed and extracted lower seam by bord and pillar mining, on the stress distribution in the longwall panel in upper seam. Studies revealed marginal increase in horizontal and shear stress as longwall face passes above goaf to the virgin area present in lower seam. Stress distribution over chock shields was considerably affected when the face in upper seam reached 15-25m zone above the galleries in the lower seam. A clear influence of the presence of solid coal, galleries and goaf in lower seam was found in the loading of longwall panel in upper seam.

Jan 1, 2007

By W. E. Pittman

The Bureau of Mines, as part of its Health and Safety Technology Program, is conducting research on the use of ground penetrating radar (GPR) for mine hazard detection. GPR offers a possibility of mapping immediate below-surface geologic conditions, including faulting and other anomalies, thereby exposing potential safety hazards to miners. This report summarizes a literature review of the current status of GPR research in and outside the Bureau.

Jan 1, 1984

By T Baumgartl, R I. Maczkowiack, O White, P D. Erskine

Queensland legislation, industry codes and policies relating to mine rehabilitation and closure create the expectation of successful progressive rehabilitation and that the post-mining environment is being returned to a condition suited to a pre-agreed, beneficial end use. Yet none of the rehabilitated mined land in the Bowen Basin has been certified as successful by authorities suggesting there is a gap between current rehabilitation and the full environmental outcomes that the legislation could deliver. We tested the veracity of this perspective and reflect on where responsibility for any discrepancy lies.We first reviewed current Queensland legislation and industry codes relating to stakeholder engagement, rehabilitation, closure planning and post-mining land use. We tested the accessibility of the documentation trail for several recent coal-mining projects in the Bowen Basin and examined the level of detail in approval documentation. We then assessed the rehabilitation performance reports of these mines in relation to the contents of their approval documents. Legislation, guidelines and codes repeatedly emphasise the need to plan for closure before mine operations begin and to progressively perform rehabilitation with an agreed end-use in mind. Early stakeholder involvement in these processes and transparency of actions and outcomes are also encouraged by government publications. Overall, in terms of transparency, we found that relevant documents are generally available to the persistent enquirer. However, the rehabilitation and closure undertakings given in both mine company and regulator documentation were commonly generic and rehabilitation obligations were not explicitly incorporated into rehabilitation plans. Rehabilitation reporting was also weak in that no distinction is required between successful and unsuccessful revegetation, nor to closure objectives and mine completion criteria. Responsibility for the apparent disconnect between regulatory intent and actual performance appears to begin with the regulator too readily allowing generic information and in not requiring performance reporting to correspond with approved post-mine conditions. As a result, companies may have a much greater rehabilitation and closure risk than mine management expects. More poignantly, the checks and balances that are in the legislation are not yielding the environmental outcomes of which they are capable.CITATION:White, O, Maczkowiack, R I, Erskine, P D and Baumgartl, T, 2012. Walk or talk - Is the current mine approval process in Queensland delivering rehabilitation and closure success?, in Proceedings Life-of-Mine 2012 , pp 59-68 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By Kieran Black

The immediate roof lithology at United Colliery is extremely variable and provides a challenge for the design of secondary support. Support design in recent longwall installation roads at the mine has been carried out using strata management techniques. These techniques allow a robust yet economical secondary roof support design to be achieved. Analysis of roof lithology and roof displacement during first pass driveage are used as a basis for the optimisation of the secondary support design prior to roadway widening. This paper will demonstrate the application of practical strata management techniques in the optimisation of secondary roof support in six installation roadways at United Colliery. The experience gained from the installation roadways for LWs 1 to 5 will be briefy discussed. The experience from LW 6 will be discussed in greater detail. The paper will describe the strata management system that was used, including mapping, borescoping and extensometry, as well as the development and application of a Trigger Action Response Plan (TARP).

Jan 1, 2007

By N. Reddy

The influence of local geology and rock mass characteristics on deformations during a rockburst caused by a controlled blast was studied. This was done by means of visual examination, mapping and photography both before and after the blast. We found that the ejected material was bounded mostly by fractures associated with the bow-wave fracturing and bedding surfaces and that existed prior to the blast. Most of the damage was caused by shake-out. This information is important input for the design of rockburst resistant support systems under conditions of moderate stress.

Jan 1, 2001

By Gerard de Vries

pipeline industry and are still growing in size. Liquid epoxy and polyurethanes are an excellent choice for whatever the aggressiveness of the substance transported and whatever the harmful outside influences, maximum protection is required. They can be used as coatings on all kind of pipelines varying from the mainline coating to the field joint coating. Compared with traditional systems like dual layer FBE and 3-layer polyolefin there are some benefits to be considered like easiness of repairs, amount of coats, application temperature and film thickness. The interior coating renders the pipe surface so much smoother that considerable savings can be realized in pump stations. Apart from the interior of the pipeline, the industry is faced with new challenges like higher operating temperatures of lines and an emphasis on product benefits in order to save money. Key words: liquid epoxy, liquid polyurethane, phenolic epoxy, pipeline, field joint coating, internal coating, corrosion control

Jan 1, 2006

By René de Batz

From 1754 to the end of 1895 the production of gold in Russia had been approximately as follows: Kilogrammes. Russia proper (Finland and the Caucasus),. .. 890 The Ural Region,........505,386 Western Siberia,........116,937 Eastern Siberia,........1,218,372 Total,.........1,841,085 of the value of more than $1,200,000,000.

Jan 1, 1899