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By Burns K. L

Keyboard patterns of hundreds of minor faults with vertical displacements of 3 mm to 2 m occur within the Greta coal seam and cause serious mining problems in collieries. Many of the faults are concentrated in linear zones termed swarms. One swarm is 600 m wide and more than 800 m long and others are of comparable size.The minor faults between the swarms are normal and are relatively widely spaced and show dip-slip movements, but the faults within a swarm are clustered and show strike-slip and oblique-slip movements. Fault swarms ofthis size and frequency have not previously been described from the Sydney Basin or on a comparable scale elsewhere but appear to be a widespread phenomenon in Australian coalfields. The faults are assigned to classes onthe basis of orientation which are then assigned to sequential phases I to IV on the basis of offsetting relations between representatives of each class. Phase I faults are minor thrusts. Phase IT, Ill, and IV faults are concentratedin the swarms and show sinistral strike-slip and normal dip-slip movements. The interference of slickenlines indicates that multiple movements have occurred within a single phase; their order is (i) strike slip (ii) dip slip and (iii) oblique slip. All faults truncate and post-date both cleat and sedimentary "stone" dykes.Phase I minor thrusts trend at a high angle to the Hunter Thrust and are considered to predate the Late Permian movements on the Hunter Thrust. Phase II and III minor faults are younger and may be any age between the latePermian and Tertiary.

Jan 1, 1978

By Gerrit V. R. Goodman, Fred N. Kissell

The issue of miner safety in case of an underground mine fire has been extensively examined by both government and industry. These efforts have intensified in recent years following a number of fatal fires at underground coal mines. As a result, there is an increasing interest in the reliability of coal mine escapeways during a mine fire. This paper discusses the use of fault tree analysis for evaluating escapeway reliability. A fault tree is developed using standard logic formulations. It is later evaluated using commercially available software. The computer model uses Boolean reduction to obtain the minimal cut sets and minimal path sets of the tree. A brief analysis is also conducted to determine the occurrence probability of the TOP event. This study shows that fault tree analysis is a viable means of analyzing escapeway reliability. The cut and path sets reveal those event sequences leading to fatalities. Such information is useful in safety training and accident prevention. The probability of the TOP event shows the frequency of occurrence for fatalities in an underground mine fire. The usefulness of this value, however, is limited by the accuracy of the data for the initiating events. For mining events, the data is difficult to estimate precisely.

Jan 1, 1989

By P. Coleman, J. C. Kerkering, S. Iverson

A fatal accident may result when a dozer is driven over a hidden void in a coal surge pile and the dozer falls into the void, burying and suffocating the dozer operator. This type of accident was analyzed by researchers from the Spokane Research Laboratory of the National Institute for Occupational Safely and Health using inexpensive fault-tree programs that had been developed, for use on a personal computer. Fault-tree analysis is a systematic safety-analysis tool that proceeds deductively from the occurrence of an accident event to the identification of the root causes of that event. The analysis identified basic and intermediate events that led to the burial of the dozer and graphically depicted the interrelationship between the basic events as well as the intermediate events leading up to the accident. A sensitivity analysis on assigned probabilities showed which events had the greatest influence on dozer burial in a coal surge pile. Operational guidelines and engineering controls are suggested to decrease the probability of a burial event.

Jan 1, 2002

By Harold Hopkins

THE Wright-Hargreaves mine is one of a group of seven mines long active in the Kirkland Lake district, Ontario. Detailed geological reports and maps covering the area have been published by the Ontario Department of Mines (1,3)t. Though all these mines work several productive veins there is one vein which is common to all and is known as the North Vein of the camp?not that it is the most northerly vein mined, but it is the more northerly of the two major veins of the camp. At the Wright-Hargreaves mine there are in all ten important producing veins, and most of them have a N.60°-65°E. strike and in general a steep southerly dip. It is a common belief that most of these veins lie along faults but it will be shown that whilst this is true of some of them it is not true of all, and also that a vein may lie in a fault along part of its course and elsewhere fill a fracture in line with the fault, this being a consequence of rotational movements that took place during faulting. The paper describes the history of faulting at this mine in particular, makes observations on the principal pre-ore fault, and describes the method used in solving the movements on the post-ore faults. Other details of geology are not discussed except to mention here that our main veins lie almost entirely in the syenite porphyry stock except on lower levels close to the east boundary of the property, where the North vein leaves the porphyry to enter the greywacke.

Jan 1, 1940

By C Buchanan

For a long time there has been a known relationship between the northern Heavy Mineral (HM) deposits of the Murray Basin to the extensive north east trending ridges in the area. These ridges have been a targeting tool for exploration and have uncovered some significant discoveries, some of which have turned into mining projects. Bemax’s Ginkgo and Snapper deposits are good examples of how the faulting helped create an economic deposit but also result in significant planning issues in the exploitation of these deposits. Material balance, induration and pyrite issues have been made easier to manage through good geological understanding of the deposits.

Aug 22, 2011

This paper records the observations of faulting in the Black Star mine workings. By classifying the faults into two groups, i.e., strike faults and transverse faults, and by pointing out the differences between the groups and their effects on the silver-lead-zinc orebodies, a time relationship between the two groups of faults and the sulphide mineralisation is suggested.GENERAL GEOLOGY AND MINERALISATIONFolding and faulting are closely related to the mineralisation in the shales by silver-lead-zinc and iron sulphides.Commonly the various sulphides are fine-grained and closely associated with one another. However, exceptions do occur locally, where massive coarse galena, sphalerite, pyrite, and to a lesser extent chalcopyrite, have been observed singly or closely associated one with the other.In the main, the sulphide mineralisation forming the orebodies occurs as replacement of, and infilling along, the sheared bedding planes of the finely bedded shale host rock.The shales in general strike north-south with an average dip to 60° to the west; strong shearing along the bedding planes is evidenced by much slickensiding and slaty cleavage.Sequences of finely bedded shales of varying stratigraphic thicknesses alternate with very. massive beds, and it is in the more highly sheared thinner beds that the greatest concentration of sulphides occurs. The unmineraIised massive beds of shale, 11 in. up to 12 in. in thickness, occur singly or in groups between, and to a lesser extent. within, the orebodies. The massive beds resisted sulphide replacement and impart to the orebodies a most prominent banded structure.

Jan 1, 1953

FaulIing west of the Mount Isa mine is described and is shown to be related to three groups of folds that have been recognized in the area. The first period of faulting postdates the first generation folding; these faulIs are regional faults (tectonic discontinuities) which are folded by second generation folds. The faulting accompanying the second generation folding divides the area west of the Mount Isa mine into four structurally and metamorphically identifiable blocks. The most prominent of these second generation faults is the Mount Isa Fault, which is characterized by a number of distinct zones of intense second generation folding and the presence of localized layers of mylonite. Only limited evidence for brittle deformation has been observed and the major movement appears to be associated with the plastic deformation of the rocks. Confined to the areas of second generation folding in the Mount Isa Fault are numerous third generation kink folds. A detailed description of the Mount Isa and other faulIs is presented together with evidence for their existence. The displacement accompanying this faulting cannot be established because of the complexity of the structure.Postdating these faults and all the folding of the area are minor cross faults.

Jan 1, 1973

By Vicki Tschirhart, Bill Morris, McMaster University

A new method for mapping faults within basement rocks underlying the Thelon Formation and glacial overburden was developed and tested in the Aberdeen Sub-basin. This method utilizes newly acquired aeromagnetic data, the Blakely algorithm for defining magnetic source edges, a calculated dip-direction map, a digital elevation model (DEM) derived from the Canadian Digital Elevation Database, and the positions of identified, inferred and newly mapped faults that are within and adjacent to this sub-basin. Combining these data revealed three age groups of faults. One group is seen only on the DEM; these faults are young brittle structures that have no effect on the sub-Thelon basement unconformity, and are not visible on the dip direction map. A second group is evident on the dip direction map but not the DEM; these faults are old basement structures that did not propagate upward through the Thelon Formation. The third group is expressed on both the DEM and dip direction map; these faults are also old structures that propagated upward during and/or after deposition of the Thelon Formation. The latter group of faults may be of greatest interest for uranium exploration, with reactivation increasing their potential to serve as conduits to transport uranium-rich fluids and focus deposition at or near the unconformity surface. This methodology has promise for comprehensive mapping of basin faults and tracking the tectonic development of the whole Thelon Basin through time.

Jan 1, 2013

By N. I. Fisher, J. Shepherd

Abstract-Statistical studies have been carried out on structural geological data collected across a large zone of roof failure 600 m (1968 ft) wide and at least 800 m (2642 ft) long in the Greta coal seam at Aberdare East Colliery. Two swarms of hundreds 2 of minor, normal faults with throws commonly between 3 and 300 mm in the room and pillar workings are broadly coincident with roof failure. The faults have been classified into dip slip and oblique and strike slip types. Roof conditions have been classified into good; troublesome with subclasses scaly, heavy, gutter falls and wide, flat-roofed falls; and severely failed with subclasses very heavy roof, gutter falls and dome falls. Troublesome conditions are defined as those in which the height of the fall is less than or equal to 0.3 m, and severely failed conditions as those in which the fall height is greater than 0.3 m. Comparison of faults, roof conditions and mining rate on a shift basis indicates that faults and roof failure are much more important than machine breakdowns in reducing mining rate. The effect of faults on roof conditions has been quantified using a concept called the "zone of influence, " a rectangular area around a fault in which the fault has potentially deleterious effects. The spatial comparison of fault "zones of influence" with areas of roof failure using Spearman's rank correlation coefficient shows that, while normal dip slip faults do not appear to be associated with roof failure, oblique slip and strike slip faults appear to be associated with roof classed as severely failed. The "zone of influence" of an oblique slip fault may extend up to 3 m on each side of it in the headings and up to 1.14 m in the cut-throughs. The fault "zone of influence" has geomechanical implications for the design of mine openings and possibly represents the maximum length of a cantilevered roof beam likely to fail during mining, owing to a fault. Roof conditions could possibly be predicted in blocks of virgin coal if the type of fault could be identified in oriented drill cores.

Jan 9, 1978

By N. I. Fisher, J. Shepherd

Statistical studies have been carried out on structural geological data collected across a large zone of roof failure 600 m (1968 ft) wide and at least 800 m (2642 ft) long in the Greta coal seam at Aberdare East Colliery. Two swarms of hundreds of minor, normal faults with throws commonly between 3 and 300 mm in the room and pillar workings are broadly coincident with roof failure. The faults have been classified into dip slip and oblique and strike slip types. Roof conditions have been classified into good; troublesome with subclasses scaly, heavy, gutter falls and wide, flat-roofed falls; and severely failed with subclasses very heavy roof, gutter falls and dome falls. Troublesome conditions are defined as those in which the height of the fall is less than or equal to 0.3 m, and severely failed conditions as those in which the fall height is greater than 0.3 m. Comparison of faults, roof condition and mining rate on a shift basis indicates that faults and roof failure are much more important than machine breakdowns in reducing mining rate. The effect of faults on roof conditions has been quantified using a concept called the "zone of influence," a rectangular area around a fault in which the fault has potentially deleterious effects. The spatial comparison of fault "zones of influence" with areas of roof failure wing Spearman's rank correlation coefficient shows that, while normal dip slip faults do not appear to be associated with roof failure, oblique slip and strike slip faults appear to be associated with roof classed as severely failed. The "zone of influence" of an oblique slip fault may extend up to 3 m on each side of it in the headings and up to 1.14 m in the cut-throughs. The fault "zone of influence" has geomechanical implications for the design of mine openings and Possibly represents the maximum length of a cantilevered roof beam likely to fail during mining, owing to a fault. Roof conditions could Possibly be predicted in blocks of &gin coal if the type of fault could be identified in oriented drill cores.

Jan 1, 1979

The Favona Underground Project is located approximately two kilometres east of Martha Mine Open Pit in Waihi, 150 km south east of Auckland, New Zealand.   The underground reserve of 354 koz Au contained in resources of almost 600 koz lies within 600 m of the existing process plant presenting an attractive development target in a challenging environment.   The Martha Mine Open Pit is surrounded by urban housing on the north western edge of Waihi township and the Favona Underground abuts residences on the eastern edge of town. Environmental, community and social licence aspects influence project strategies as the new underground mine extends mining in a town that is planning for closure of current open pit operations in late 2006.   The Favona Underground Project has successfully passed through a detailed feasibility study, the third stage of the five stage Newmont project appraisal system. Methodologies used in the feasibility study and parallel permitting draw on a high level of stakeholder involvement to streamline the development and permitting phases.   This paper discusses the project appraisal process and design innovation required for developing an underground mine adjacent to town.

Jan 1, 2004

By JESSE L. MAURY

DEVELOPMENT of new gold mines in Canada since the price of that metal was increased in 1932 and 1933 has been of interest and importance to many of us. The day-by-day story has given an impression of aggressive effort and enough good luck so that the spirit of enterprise has been encouraged. It is the purpose of this article to report the results of a statistical appraisal which give emphatic numerical confirmation to this impression, together with certain side lights on the costs of development and equipment of new mines. The data presented have been taken from all readily available published sources up to the close of 1938 and are representative of that year. A. B. Bower did a large part .of the spadework and Weston Thomas offered many helpful suggestions.

Jan 1, 1939

Data recently released indicate substantial improvement in mineral industry performance for 1984. Business plans to increase plant and equipment spending in 1984 by 14.8 percent, according to a recent survey conducted by the Commerce Department's Bureau of Economic Analysis (table 1). In contrast, capital spending by all industries declined 4.8 percent in 1983 and 2.3 percent in 1982. The latest estimate of planned expenditures for 1984 is $2.2 billion higher than the comparable estimate based on the survey conducted in late January and February 1984.1/ [ ] Of particular significance to the U.S. mineral industries are the 15.5-percent increase in capital spending planned by manufacturing in 1984 and the planned 18.6-percent increase in spending by durable goods manufacturing, where the largest increases are planned in the transportation equipment (26.4 percent) and electrical machinery sectors (23.5 percent). Capital expenditures in manufacturing declined in both 1982 and 1983.

Jan 1, 1984

By H. P. Ehrlinger

The Illinois State Geological Survey added Minerals Processing to its capabilities in 1966. Subsequently, the Minerals Processing Team and several Geologists collectively thought what neither would have thought of separately. The results included a number of projects. discussed here are: 1) The Utilization of the Fines from Kitty Litter as a Bonding Agent for Iron Ore Pellets; 2) Separating Plant Waste from a Commercial Silica Sand Producer into two marketable products, including a closely sized Silica Sand; 3) Marketable Feldspar Sand and Silica Sand from Dune Sands near the Kankakee River; and 4) A Method for Making Metallurgical Grade Fluorspar more desirable as Blast Furnace (Steel) Feed.

Jan 1, 2003

By H. Palza, C. Ihle, S. Contreras

"Processing of minerals, particularly treatment of tailings, has been increasingly challenged by the presence of clays in the feed of thickeners. This occurrence is expected to become increasingly important given the nature of ore deposits currently being exploited and those that have been recently discovered. In sedimentation operations (solid-liquid separation), industrial flocculants often fail to coagulate clay-containing fines, generating supernatants with high levels of turbidity, thus implying operational problems. Recently, it has been reported that graphene oxide (GO), a graphite derivative with high oxygen-containing groups, could enhance the flocculation of clay systems, due to the interaction between clays and GO functional groups. In the present work, we investigated the effect of doping industrial flocculants (commercial polyacrylamide) with GO on the floculation of kaolinite suspensions in a solid-liquid separation stage. Separation performance was evaluated by studying flocculation kinetics using a focused beam reflectance measurement (FBRM) instrument, in a set of batch tests. A statistical analysis of the flocculation kinetics and floc population distribution was further carried out. Our results suggest the existence of a synergistic effect between the studied flocculants and GO. This effect is observed as a decrease of clay fine contents in the supernatant, thus improving solid-liquid separation eficiency for high clay containing tailings. INTRODUCTION Copper, given its mechanical, physical and chemical characteristics, is a critical material for the progress of society and so has been from early stages of mankind. Demand for this metal has increased due to the growth of cities and the technological explosion, leading to increase current mining production and reinforce the efforts in exploration for new deposits (Elshkaki et al. 2016). As copper-rich deposits are being depleted, it has been necessary to develop proper technology to mine deposits of lower grades and more complex mineralogies, keeping in mind that the economic window that allows the exploitation of them is reduced by the increase on operating costs (Crowson 2012 and Northey et al. 2014). High clay bearing minerals are found in many of those low-grade copper deposits, and they induce problems in all stages of the mineral processing route (Taner and Onen 2016). Particularly, in the solid-liquid separation stage, the flocculation process fails to remove the clay fraction from suspension and it leads to operational issues such as filter damage, overconsumption of reagents and the need to add an extra clarifying step for the recovered process water. Those problematics pose an interesting challenge."

Jan 1, 2018

By H. Yavuz

A Numerical modelling study using the two dimensional finite difference code "FLAC" was performed for investigating the ability of numerical modelling to predict the performance of yielding pillars. The model was verified by comparing the stress and deformation data obtained from a yield pillar trial application at Welbeck Colliery, a UK coal mine. Two entries with-a 10 m intervening pillar were modelled. Both for development and for side abutment loading stages, the vertical stress measurement data over the pillar and side abutment and deformation measurement data in the roof and floor of the trial entry were compared with the results obtained from the model. Two difficulties were encountered, unavailability of data for caved rock and for the yielding pillar material. These were overcome by back analysis to estimate the unknown field properties of the pillar material and caved rock from known properties of these materials. Results from this model are given and the predictive capability of a finite difference model for two entry yield pillar applications is discussed.

Jan 1, 2001

By Sastry Putcha, Vamshi Vemula, Aneesh Goly, Kumar Allady

Current dynamic testing practice to obtain pile total capacity will not yield optimum capacity due to the strain incompatibility between the side and tip resistances during driving. Superposition of end of initial drive- static tip capacity and the peak static skin capacity during beginning of restrike and adding them is the preferred method. The FDOT method determines independent pile static tip and skin capacities in real time analyzing appropriate blows from the embedded tip and top data of the Embedded Data Collectors (EDC). This data is collected through a wireless radio transmitter, receiver, and laptop software. The approach utilizes EDC tip and top data and nonlinear single degree of freedom system to satisfy force and energy equilibrium with a global genetic inversion analysis. Top impacted energy equals at pile tip as sum of Static, Damping and Inertial energy providing independent tip resistance. With EDC sensors as boundary conditions, pile is divided into desired segments and using global inversion techniques one dimensional equation is solved for independent skin friction for every blow. EDC data compared close static load test results. The EDC - FDOT method has enabled cost effective 100% testing of driven piles cost effective. INTRODUCTION Historical documentation has shown that not only driven piles have a long history of usage but also continues to advance unceasingly till today. Historians placed the first pile driving using timber piles in the 4th century BC. While modern pile driving systematically started around nineteenth century, the credit for conceiving the idea of the applicability of wave equation to driven piles goes to David Victor Isaccs of Australia. His 1931publication “Concrete Pile Driving Formulae” provides the basis for modern pile driving using stress wave theory. He felt that the dynamic formulae then in use lacked the capability of detecting integrity and hence developed stress wave theory. This work was further developed starting in 1938 by W.H. Glanville and colleagues of British Building Research Board as they developed the first solution to the wave equation. But these early efforts have really taken off only with the advent of computers. E.A.L. Smith (1960) published ‘Pile Driving Analysis with the Wave Equation’ and provided first numerical solution to the wave equation. Within few years, the FHWA funded research and in due course this effort ushered the era of externally instrumented pile driving.

Jan 1, 2018

This paper describes a simple finite element (FE) modelling approach which leads to the computation of seismic energy release rate (ERR) and strain energy storage rate (ESR) which result from mining. The concept of critical strain energy is introduced as a means to help evaluate the strainburst potential in mine structures. A new, energy-based, burst potential index (BPI) is proposed. The use of ERR, ESR and BPI is demonstrated by a cut-and-fill stope case study. The merits of using such energy parameters in the interpretation and analysis of strainburst phenomena are discussed. While the study gives promising results, site-specific back analyses would be required to first calibrate the model and fit it with the local mine conditions, before it can be adopted as a routine design tool.

Jan 1, 1999

By I. B. Schalamuk, R. E. de Barrio, M. J. Pons, M. B. Franchini, L. Meinert

"Several Fe, Fe-Cu, and Cu-Ag prospects hosted by Mesozoic carbonate-rich sedimentary rocks that were intruded by diorite stocks define an approximately 20 × 200 km belt along the Andes Cordillera of southwest Mendoza province, Argentina (34°-36°S). This belt includes the Hierro Indio and Vegas Peladas Fe skarns, Las Choicas, and several other Cu-(Ag) prospects.The main features of the Fe skarns include: association with mantle-derived middle Miocene (~15-11 Ma) diorite stocks and sills; widespread alteration including epidote ± amphibole ± magnetite endoskarns, and zoned garnet (Grs0-66 Adr32.5-100) ± magnetite ± pyroxene (Di24-50 Jo2-9 Hd74-41) exoskarns formed from oxidized, saline, high-temperature brines (530º-660ºC; 60-70 wt.% NaCl equiv.); and magnetite-hematite orebodies associated with quartz ± epidote ± calcite ± actinolite formed at lower temperatures (290º-436ºC) from saline fluids (32-50 wt.% NaCl equiv.) of magmatic origin.West of the Fe skarn belt, the Valle Hermoso district covers more than 300 km2 and hosts several poorly known Cu-(Ag) prospects (estimated 30 Mt with 1.5% Cu and 20 g/t Ag). These prospects share many characteristics with the iron oxide copper-gold-type systems and manto-type Cu deposits of northern and central Chile. One of the prospects (Las Choicas) is located at the apex of a regional 015°-trending anticline, along the contact of stratified calcareous sandstone and limestone (Neocallovian-Oxfordian) with a diorite pluton. This pluton has positive Ta and Nb anomalies (on normalized diagrams) and a high Ti content, features uncommon in Miocene diorites associated with Fe skarns and of magmas derived from sub-arc mantle sources. Alteration at Las Choicas includes early widespread chlorite + calcite ± albite ± scapolite ± ilmenite or titanite ± apatite, and local actinolite ± hematite ± biotite alteration of diorite and sedimentary rocks along contacts. Later Cu mineralization (1%-10% Cu) is associated with calcite ± albite ± quartz alteration in fractures, vein networks, and crackle breccias. Mineralization is zoned from bornite ± chalcopyrite ± millerite with Zn, As, Mo, Ag, and U anomalies in the main orebody, through chalcopyrite-rich breccias with Zn anomalies, and chalcopyrite ± tetrahedrite vein networks with Sb, As, Ag, and Zn anomalies in the uppermost zone, to a Cu-depleted pyrite-rich envelope with Co anomalies, and finally to late, barren calcite veins in distal zones."

Jan 1, 2007

By Pingchao Ke, Zhihong Liu

Fe(III)-As(V) precipitates were synthesized from the Fe(II)-As(V)-SO42--H2O system at 90°C in initial Fe(II)/As(V) molar ratios of 4.0 and 5.0, respectively. The synthesis were carried out by introducing oxygen gas into the system to oxidize Fe(II) ions into Fe (III) ions, and at the same time, adding aqueous sodium carbonate solution into the system to neutralize the acid released by the hydrolysis reactions, with the purpose of keeping the pH constant at 1.5±0.05. The precipitates obtained were characterized by XRD, chemical composition analysis, SEM, XPS, and Raman spectrum. The results indicated that the particles in the precipitates were in the morphology of irregular aggregation with their sizes in the range of about 1–4 µm. The precipitates consisted of scorodite, ferric arsenate and amorphous hydrated ferric oxide, of which amorphous hydrated ferric oxide formulated as Fe(OH)x(SO42-)y. The characteristic XPS peaks of Fe-AsO43- and Fe-O in the precipitates located at 711.8 and 713.3 eV, separately, and the existence of amorphous hydrated ferric oxide led to two series of shake off lines developed over the end of high binding energy of Fe2p XPS. The precipitates were stable in TCLP tests at pH 4.93 for 60 hours with the arsenic concentrations in the leaching solutions being 0.27 mg/L and 0.59 mg/L for the precipitates prepared in the initial Fe(II)/As(V) molar ratios of 4.0 and 5.0, respectively. The tests for the long-term stability of the precipitates were carried out by leaching them for 40 days at 25°C under various media in the pH range from 9.50 to 10.57, and the results showed that the precipitates synthesized in this study were much more stable than those by previous researchers.

Jan 1, 2017