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In preparing a paper such as this it was thought that the Newstan Colliery Company Ltd., being comparatively new, would need some introduction to mining people in general.The Newstan Company was formed by the Joint Coal Board in December, 1948 during a period of acute coal shortages. The Company took over the holdings of what were known as the Olstan and Northumberland Collieries, situated at Fassifern, alongside Lake Macquarie and adjacent to the Great Northern Railway, within easy rail access of Sydney and Newcastle, as shown on the locality plan (Fig. 1).The Company was developed in order to produce steaming coal for the power house trade and has continued its activities in the steaming coal trade since its inception. The Olstan and Northumberland collieries were together producing some 300 tons per day when the Company was formed, and it was from this foundation that the colliery was built. The planned development of the Company has been along the lines of producing coal by modern, highly mechanised methods, together with the preparation of theproduct for the consumer, to the highest degree possible consistent with up to date methods.In the comparatively short time of 5t years the mine has developed from a small hand-won coal unit to a high capacity modern mine, one of Australia's largest producers, with an output capacity as high as 3,000 tons per shift.

Jan 1, 1954

By R. V. Ramani

"A computer simulation model of a dragline has beer developed for the study of alternative dragline deployment schemes for varying geological and mining conditions. In this paper, the mathematical aspects of the model, the input data and output results are discussed. An application of the model to a coal mine in eastern Kentucky is presented.IntroductionDraglines are very productive machines. To extend their operating ranges, they are operated in several modes such as advance benching, key cut, extended benching and pullback. Unfortunately, these variations result in low machine productivities. Appropriate methods to operate these machines must be developed on the basis of detailed analyses of dragline performance under varying geological and mining conditions. There are several standard engineering procedures for the selection of dragline, and design of a dragline pit (Ramani, Iroegbu and Manula, 1976). However, the complex interrelationship which exists among equipment, methods and natural conditions can be quantified only through orderly and systematic experiments.Computer simulation is well suited to studying these types of equipment selection and method layout problems. Several alternatives can be analyzed in a relatively short time by the modification of input variables. Also, the application of computer simulation models can significantly reduce the manpower and cost required for such analysis."

Jan 1, 1985

Urban development to the south of Sydney is approaching areas of current and proposed coal mining. Already some structures and residential areas are affected by mining subsidence.Subsidence resulting from either conventional pillar extraction methods or longwall mining has been monitored for 15 years to enable the characteristics of the surface deformation to be determined.The vertical and horizontal displacements of survey stations on the surface are monitored and the results arc used to calculate subsidence, changes in slope of the surface, curvatures along the subsidence profile, and the ensile and compressive strains. These features are in turn related to the underground extraction to give a description of surface subsidence and the development of subsidence with time.Subsidence investigations have been carried out over all or part of the workings of six collieries in the Southern Coalfield.Two case histories illustrate the procedure in the investigation of subsidence phenomena. The first example is the study of the subsidence over a series of longwall panels in one seam and the second is a study of subsidence over pillar extraction in two seams one above the other. From the results of the investigations the effects of panel widths on subsidence are determined.This and other information assists mine planning in areas where surface movement and deformation are important considerations.

Jan 1, 1980

By N. Charue

An international prediction event was carried out within the framework of a 30-pile testing program organized in a sandy soil in Belgium (Limelette). That program called upon sev­eral testing methods: static load tests, Statnamic testing, and dynamic testing. This paper provides a summary of received predictions and results obtained from the static pile load tests, which were carried up to failure of the instrumented piles. The comparison between predictions is made using load-settlement curves with reference to the results of the static load tests. The predictions are based on a geotechnical approach using an extensive soil investigation program and a dynamic approach using the dynamic load test data.

Jan 1, 2002

The Main Seam occurs in two 'pods', termed North and South, separated by an east-west oriented 'want' zone (most probably a palaeo-channel). The seam on either side of the 'want' area reaches thicknesses of over 30 metres but the North Main Seam adjacent to the 'want' zone has been split into multiple seams of 10 to 15 m thickness. Rock types in the inter-burden of this area are characterised by inter-bedded sandstones and carbonaceous mudstones varying in thickness from 0.5 to 5 m. In the South Main Seam, an area of un-split coal exists and is characterised by few inorganic partings. Overburden in this area varies geographically from relatively thick mudstones in the south and east part of the coal deposit to inter-bedded sandstones and carbonaceous mudstones adjacent to the 'want' area. The sandstone/mudstone overburden probably represents a splay or splay-channel complex emanating from the larger 'want' area palaeo-channel. Modelling lithological variability is of use because it is one of the factors used in predicting cavability and roof support system design. The coal in both the north and south deposits were found to exhibit highly predictable quality and breakage parameters in relation to the coal geometry. Although ash yield and sulphur are mostly low and not variable, volatile matter and thus fixed carbon, varied in relation to seam thickness. In general, volatile matter (dat) decreased and moisture increased with decreasing seam thickness whereas moisture increased with decreasing seam thickness. In addition to these parameters it was found that the energy needed to crush the coal was lowest at the top and bottom of the seam and, on a whole seam basis, decreased with seam thickness. All of these parameters were found to vary in relation to the vitrain band content of the coal which itself was controlled by seam geometry. These parameters can therefore be modelled and inputted into mining plans and quality control operations.

Jan 1, 1996

By H. Kazemi, G. W. Thomas, M. S. Seth

The double-porosity model of Warren and Root7 for examining pressure drawdown and buildup phenomena in naturally fractured reservoirs has been extended to intetpret interference test results. Both analytical and numerical solutions are presented. The practicality of some of the assumptions in the Warren-Root model was also investigated. The standard procedure for interpreting interference tests in naturally fractured reservoirs beretofore employed an equivalent homogeneous reservoir model. A comparison of our results with the equivalent homogeneous model indicates the latter is inadequate for early time responses. For late time responses, however, the simpler equivalent homogeneous model yields favorable results. Finally, the effects of well spacing and the magnitude of the interporosity flow parameter are briefly cited. INTRODUCTION Interference tests can be used to provide reservoir information not obtainable from conventional pressure drawdown and buildup tests. The technique involves measuring the response in one or more wells arising from a pressure perturbation introduced into another well. It has been. successfully applied to single-layer, homogeneous, unfractured, isotropic and anisotropic formations to arrive at values of well storage capacity and a measure of directional permeability.l The techniques of interference testing usually can be extended to heterogeneous systems, provided the permeability contrast between any existing rock layers is not excessive.9 In such cases, the practical interference effects in an observation well of an interconnecting heterogeneous reservoir can be predicted using an equivalent homogeneous model. The calculated properties are then average values. Russell and Prats2 have demonstrated the utility of this approach for a single-phase, two-layer system. For naturally fractured reservoirs, some different approaches usually are necessary. The major departure from homogeneous or nearly homogeneous reservoir treatment is to characterize the fractured system as an entity having "double-porosity"; namely, we suppose the existence of both primary and secondary porosity, where the former is contained within a systematic array of identical rectangular matrix blocks and the latter is contained within an orthogonal system of continuous, uniform fractures (see Fig. 1). It is sufficient to assume that the permeability of the rock matrix is so small that movement of reservoir fluids to the producing wells is entirely through the fracture network. This assumption has been validated by Barenblatt3 and .employed by others?-7 Warren and Root7 used the double-porosity model to develop an interpretation of pressure drawdown and pressure buildup tests in naturally fractured

Jan 1, 1970

By I. C. Spangenberg

The status of sampling practices in the gold mining industry in Africa was determined as an initial step in a process to standardize sampling practices in the mining industry. Twenty-one gold mines, twenty metallurgical plants, and thirteen laboratories were rated for the potential influence of the relevant sampling errors on each component of the particular sampling system. The findings of the study on the status of equipment, standards, procedures, and management principles were presented in a dissertation (Spangenberg, 20121) and are now used by AngloGold Ashanti?s mines in the quest for correct sampling practices. The information is also used to compile a guideline on leading practice procedures for sampling methods in gold mining. This article is an overview of sampling best practice found in African mining Keywords theory of sampling, best practise, sampling errors, sampling standards.

Jan 1, 2014

By R. T. Stain

Integrity testing of deep foundations is now common practice in Europe, indeed in the City of London such testing is a contractural requirement on every site. This paper is in two parts: Part 1 describes the most commonly used test methods and their applications. Part 2 presents a case history where both of the above techniques were used.

Jan 1, 1987

By L. Bergkvist

"History can provide many answers with regard to what today’s mining industry looks like and how we got to where we are today. It has always been self-evident that safety has to be given the highest priority and, throughout history, many mine workers have been injured, become ill and have even sacrificed their lives due to the way in which attempts have been made to extract the ore, often due to ignorance of the dangers being faced. In more recent stages of history we have seen certain dangers being compensated by means of higher wages and bonus systems in order to have the work carried out: one example of this is when the rock heating method was employed and the men who first went underground to put out the fires that were burning, were paid extra. The working conditions, to which these people were exposed, with smoke-filled closed spaces, shortened their life expectancy considerably and today we can ask ourselves whether it is really possible to value these efforts just by higher wages. In all mines worldwide the working environment has been improved and many mining companies have a zero vision where work-related injuries and accidents are concerned. Despite this, incidents of varying severity still occur and a continuous improvement process and ongoing training is necessary in order to constantly minimise risks and improve the working environment. Atlas Copco takes this into account in all its development and we not only review our own production units but also the needs of our customers, with regard to the machinery that is produced in order to cater for customers’ safety and production objectives. Underground mining probably started at the beginning of the 11th century when people with modest tools tried to extract ores that were present in the bedrock. Methodology has developed enormously over the years with a strong focus on increased efficiency and higher production. In different parts of the world the development is driven forwards at different rates depending on which controlling factors are regarded as necessary. Political decisions, profit goals and productivity have partly controlled the development, but the greatest factor where improvement is concerned still remains with increased understanding of the totality. During more than 1000 years since underground mining has been conducted, all individuals at all levels have constantly improved their expertise and the human element has been of great importance with regard to the development that has been made, even though technology often occupies a leading role when we describe the improvements made."

Jan 1, 2011

By J. M. Ortiz

Grade control and short-term planning are usually based on the samples obtained from blastholes. These samples may carry a large sampling and sample preparation error. At El Tesoro copper mine in northern Chile, an advance drilling grid is used for short-term planning and grade control. These drill holes are sampled well in advance, and a short-term model that incorporates several variables and sophisticated estimation methods can be prepared for decisionmaking. An additional advantage of the advance drilling samples is that reverse circulation can be used instead of conventional down-the-hole equipment, and a very careful sampling and sample preparation process can be implemented, reducing the total sampling error. Advance drilling can be performed on a wider grid than blasthole drilling, hence the decision about the grid requires assessing the economic benefit of different sampling grids. Furthermore, this process allows the cost of poor sampling and the effect of different estimation procedures to be quantified. We demonstrate the optimization of the drilling grid for short-term planning and grade control at El Tesoro mine by means of the economic evaluation of the performance of different drilling grids, with different drilling techniques (which differ in the sampling error). The methodology is based on creating dense (exhaustive) geostatistical simulations of the grade distribution over a volume defined for a production period in respect of the geological model, and assuming each simulation as the true grade distribution. Then, samples are obtained from the exhaustive simulations at a spacing similar to the advance grid to be evaluated, and a sampling error is added. The short-term estimation procedures used on the mine are applied to determine the destination of each block and the profit obtained. This profit can be compared with the maximum profit (unachievable) and with the profit under different sampling errors and grids. The results show that the current 8 x 8 m drilling grid is appropriate and by reducing the sampling error, misclassification is also reduced, leading to an increase in profit of about US$ 5 million in 4 years.

Jan 1, 2012

By Anastasia M. Suchowerska

The design of effective ground support requires a sound understanding of the pre-mining state of stress in the stratum to be mined. Irregularities in the stress field encountered during multiseam mining are governed primarily by the previous mining in the surrounding strata. The aim of this study is to quantify the effects of rock mass transverse isotropy on the vertical stress redistribution in the rock strata beneath supercritical longwall panels. Wilson?s equations for determining the stress distribution induced in and beyond a single longwall panel after it has been mined have been adopted, and a plane strain finite element analysis of an elastic medium, together with the stress changes predicted by Wilson, was used to calculate the final pre-mining stresses in the underlying strata. Values of the independent shear modulus (G¢) of the rock strata, ranging from 0.1 to 1 times the isotropic shear modulus (Giso) in the plane of the strata, and a Poisson?s ratio (?) of 0.25 have been investigated. The key finding of this study is that the predicted magnitude of vertical stress in the transversely isotropic strata beneath a mined supercritical longwall panel is larger and changes more quickly with horizontal distance than is the case for an isotropic rock mass. This finding is of significance for the design of ground support measures in multi-seam mining operations.

Jan 1, 2012

By C. A. Jeffrey

The Dirtlow Rake vein deposit, which is up to 12 m thick, contains a range of paragenetically linked replacement mineralisation styles typical of many Mississippi Valley-type deposit environments. The main ore zone lies within the solution collapse breccia domes, the more southerly of which has recently been well exposed, allowing its relationship to the associated mineral-hosting structures to be studied. The domes were largely formed during early silicification, propagated by dissolution collapse and infilled by subsequent fluorite-barite mineralisation. The location of pipes and pervasive replacement was also controlled by early silicification. Structurally controlled bow tie shears were formed as a result of fluid access at fracture-bedding plane intersections. The nature and distribution of the mineralisation styles indicate that the degree of fluid access, residence time of solutions in contact with the wallrock and susceptibility of the limestone to silicification each played a major role in dictating mineralisation

Jun 19, 1905

Application of Discrete Element Method for Simulating Feeding Conditions and Size Reduction in Cone Crushers

Sep 13, 2010

The NIOSH suite of coal mine ground control software addresses nearly every aspect of coal mine ground control planning, including geologic characterization, mine layout, pillar design, and support selection. Mine planners who use the soft-ware have access to the knowledge gained during years of NIOSH research—packaged in a simple, easy-to-use format. Several of these software packages have recently been updated and improved. Analysis of Roof Bolt Systems (ARBS) (Figure 1) helps select the proper roof bolt system design from the immense variety of available bolt types and patterns. It was developed from statistical analysis of extensive bolt performance and roof fall data. New features in Version 2 include— • The capability to analyze roof bolt systems that use two types of bolts; and • A roof support cost module that estimates the total in-stalled cost of different patterns, considering the costs of consumables, labor, maintenance, and other factors. The Support Technology Optimization Program (STOP) (Figure 2) can be used to make judgments regarding which secondary support system will be the most effective in a particular mine condition and to evaluate the advantages or dis-advantages of alternative support systems. Version 3.0 includes additional improvements: • Supports with large load-shedding following yielding can be designed based on the peak loading capability as well as the residual loading capability; • Seven new support systems have been added to the program; and • Easier access to photo gallery has been provided. The Coal Mine Roof Rating (CMRR) replaces com-plicated geologic information with a simple numerical rating that mine planners can use in many ground control applications. The CMRR can be readily integrated into a geologic exploration program, and the software package is capable of generating an AutoCAD CMRR "layer." Version 1.2 contains— • The complete CMRR database with more than 250 ratings obtained from 70 different U.S. coal seams; and • An all-new "Help" file that clearly explains all aspects of the program. Analysis of Horizontal Stress in Mining (AHSM) can help find the optimum mine layouts for control of horizontal stress. It can be used to analyze both development and longwall retreat designs, and it shows how the stress condition varies as the entry, crosscut, and panel orientations are changed. Version 2 features— • Improved graphics that enable the user to observe the effect of design changes without adjusting the display on the computer screen; and • Resource files containing information on stress map-ping, advance-and-relieve mining, stress measurements in U.S. coal mines, and other topics. [ ]

Jan 4, 2006

By R K. W Merkle, S Madoom Hussain, T Yellappa

Cr-Ni-Cu¦PGE deposits are known to occur in early Archaean mafic-ultramafic rocks. Early Archaean mafic-ultramafic (MUMF) rocks occur in the western Dharwar craton and range in size from small pods to schist belts. These MUMF pods consist mainly of meta-peridotites, tremolite-actinolite schists, serpentinites, amphibolites and metabasalts. Spinifex, nodular and ocelli textures are also present. The rocks have been subjected to greenschist and amphibolite facies metamorphism. Geochemical studies were undertaken to evaluate the possible occurrence of economically important elements in the mafic-ultramafic enclaves around the major Arsikere-Tavarkere lineament and surrounding gneissic terrain adjoining local shear zones that occur as discontinuous pods between Arsikere and Chennagiri. Talc-serpentine and tremolite- actinolite schists contain chromite which is rimmed by ferrit-chromite. A notable feature of these MUMF rocks is that they exhibit high MgO (22 - 40 per cent), total iron (8.34 - 10.01 per cent), Ni and Cr (~3000, 2800 ppm) contents, with some samples showing komatiitic affinity. The rare earth elements (REE) data show slightly fractionated patterns with enriched LREE (LREE/HREE ~5.0) and negative europium anomalies. The Pt and Pd values reach 6500 and 191 ppb. The MUMF rocks, especially those exhibiting high chromium contents and occurring near shear zones, are potential hosts for economic platinum group element (PGE) deposits.

Jan 1, 2008

By M. J. McLeod, D. R. Lux, R. P. Taylor

"The Mount Douglas Granite constitutes the eastern part of the Saint George Batholith and contains the youngest, most differentiated phases of the batholith. It also contains extensive endogranitic, low-grade. Sn- W-Mo-bearing sheeted vein systems. Early phases of the Mount Douglas Granite are coarse- to medium-grained, seriate granites that represent the slowly cooled carapace of the intrusion. Late phases are medium- to fine-grained, equigranular and porphyritic granites that were accompanied by repeated and widespread fracturing of the carapace and injection of mineralizing fluids. These granites represent a highly differentiated suite with ""A "" type affinities developed in a ""within plate"" transitional to ""syn-collision"" tectonic setting. 4oAr/ 39Ar dates for biotites from the various phases indicate emplacement circa 367 Ma.The linear distribution of some phases in the Mount Douglas Granite and the systematic orientations of sheeted veins along tensional fractures indicate structural control on granite emplacement and vein distribution. This type of relatively passive endogranitic mineralization is unique in the granites of southern New Brunswick and contrasts markedly with highly fluidized systems operative elsewhere in the area. IntroductionInvestigation of Sn-W-Mo occurrences in New Brunswick has shown that most of this mineralization is associated with late, highly differentiated phases of post-orogenic (Acadian) granitoid magmatism that occurred during Devonian and Early Carboniferous time (Ruitenberg and Fyffe, 1982; Taylor et al., 1988). The polymetallic Mount Pleasant Sn-W-Mo deposit (Ruitenberg, 1967, 1972; Kooiman et al., 1986)and the Burnt Hill W deposit are two orebodies of this type in New Brunswick. Numerous smaller deposits associated with these granitoid rocks in southwestern New Brunswick have been documented in previous investigations (Ruitenberg, 1967, 1968; Ruitenberg and Fyffe, 1982; Taylor et al., 1985; Lentz, 1985)."

Jan 1, 1988

By J. West

For many years line-of-sight (LOS) issues for underground mobile equipment is a growing focus of research. This research is a result of the numerous fatalities and injuries which occur in the mining industry and which are related to poor operator LOS. Three assessment methods are currently used to assess operator LOS of underground mobile equipment. The light filament (LF) method is a hands-on assessment method that is performed in the field. This method is not evaluated in this paper. The laser scan (LS) method of assessing equipment is a quick and reliable method that comes from the need to evaluate vehicles already located in the field. The computer simulation (CS) method can assess LOS issues using a computer aided drawing (CAD) model, which is useful for assessing current or prototype models. The purpose of the current research is to compare and validate different operator LOS assessment methods. Comparison of the results of the LS and CS visibility plots yielded similar quantifiable results. A visual comparison of the results further illustrate that the LS and CS methods are acceptable assessment tools for mobile equipment operator LOS evaluation. The visibility assessment methods are now being prepared as guidelines for the mining industry to assess current and potential designs.

Jan 1, 2007

By D. S. F. Silva

A survey of 120 recent NI 43-101 technical reports was conducted to evaluate the current state of practice regarding resource classification techniques. The most common classification techniques are based on search neighbourhoods (50% of recent reports), drill-hole spacing (30% of recent reports), and/or kriging variance (6% of recent reports). Two new techniques are proposed. The first is based on kriging variance and involves removing one or more drill-holes with the highest weights while performing kriging and using the resultant kriging variance for classification. This technique has the advantages of variance-based techniques and reduces artifacts. The second technique is based on conditional simulation and uses a moving window approach for classification at the desired selective mining unit resolution based on larger production volume criteria. This technique has the advantage of accounting for heteroscedasticity, which is a common characteristic in mineral deposits, and also reduces artifacts since a production volume scale is considered for the actual classification. The drill-hole spacing, search neighborhood, kriging variance, and simulation-based techniques are described and compared for 2D and 3D examples with regular and irregular drilling patterns to highlight the advantages and disadvantages of each method.

Jan 1, 2014

By D Craw

The Old Man Range, south of Alexandra, in central Otago consists of a package of highly folded greenschist facies schist of the Wanaka lithologic association. The range is crosscut by several east to ENE-striking high angle gold-bearing quartz veins, (eg Whites Reef and Grays Reef), which were extensively worked in the late 1800s. The range is bounded on its east side by the Old Man Fault, which separates these rocks from generally flat lying and planar Caples Terrane schist. To the west of the Old Man Fault, about halfway up the range, a large subparallel, 100 m wide fault zone strikes NNW and appears to cut off the historic veins. The fault zone consists of highly sheared and folded rocks and numerous high angle cataclasites and centimetre-scale clay gouge zones. Hydrothermal alteration is not apparent and the individual faults and shears are clay altered, possibly due to weathering, without visible quartz veins. Gold, limonite pseudomorphs after pyrite and rutile are concentrated in some of the narrow cataclasites and gouge zones. These mineralised structures are texturally similar to the gold-bearing reefs and may be structurally related. It is postulated that the NNW-striking shear zone and ENE-striking veins may be a conjugate array formed during a period of Cretaceous normal faulting.

Jan 1, 2004

By D. C. Goldring

Many high-grade iron ores are considered to result from the supergene enrichment of banded iron formations. The secondary processes may be related to either present-day or ancient erosion cycles and may reach a considerable depth. Other high-grade ores hosted by banded iron formations are regarded as either sedimentary or metamorphic in origin although often also subjected to the secondary processes. The evidence for this multiplicity of origins is reviewed with descriptions of selected deposits: Kedia d'Idjil and M'Haoudat in Mauritania, Bomi Hills and the Nimba Range in Liberia, the Itabira district in Minas Gerais, Brazil, and El Pao in eastern Venezuela. Emphasis is placed on the recognition of textures that show that some ores are tectonites, the precursor materials having undergone pervasive deformation accompanied by metamorphism. The question whether such ores are pre- or syntectonic is difficult to resolve, the evidence being inconclusive, but a diagenetic/early deformation origin is preferred. The possible range of origins has to be taken into account in exploration, particularly as regards the depth of drilling, and in the characterisation of ores for metallurgical use

Jul 1, 1991