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By T. Bajpayee, J. Ellenberger

Microseismic monitoring and evaluation is one aspect of the National Institute for Occupational Safety and Health (NIOSH) research program. Roof falls are often preceded by a period of elevated microseismic activity, but not all periods of elevated activity result in a roof fall, nor do all roof falls occur after some amount of elevated activity. The objective of this study is to review periods of elevated microseismic activity and determine whether fracture activity rate can be used to anticipate the initiation of roof falls. The study was carried out at an underground limestone mine where major roof falls are associated with excessive horizontal stress. The progression of roof falls was detected by the microseismic signature produced by the rock falling from the mine roof onto the mine floor, which is termed a roof fall impact event. A total of nine elevated fracture activity periods that resulted in seven major roof falls were examined. It was observed that elevated fracture activity preceded the initial roof fall impact event in three out of four major roof falls. The initial impact event was not identified for the remaining three roof falls. Fracture event rates were analyzed and a roof fall alarm trigger of five fracture events in a ten minute time period was established for this test case. The fall alarm trigger was tested against six of the elevated activity periods. Four roof falls occurred in the six periods of elevated activity, and two would have triggered the alarm before the roof fall occurred, while two false alarms were generated. The results show that limited success would have been achieved by the microseismic system as a roof fall alarm trigger. However, the trigger would have been successful at warning of the onset of elevated activity, allowing mine employees to respond appropriately. The study highlighted some issues with implementing such a system in an operating mine, including the need for real time identification of fracture related microseismic signals among mining induced signals, and accurate location and identification of fracture clustering.

Jan 1, 2007

By D. Rutledge

Discrete (digital) signal processing techniques are proving to be very valuable tools for miners using the block cave method. Waveform analysis of different measured signals associated with active mining provides valuable information on production dynamics and safe operation of the mine. For example, correlation of the three-dimensional surface displacement velocity waveform and the production output waveform reveals a remarkably predictable time-varying physical process. In this paper, the authors discuss the signal processing techniques used to study these relationships, as well as the related implications for mining.

Jan 1, 2008

The distribution or the userul minerals or Tasmania is so closely connected with the geological structure of the island that it will be convenient to briefly recapitulate the principal ract or its geological history, before describing the ore and other deposits. In many cases these present features which are very puzzling in the absence of knowledge of the structure of the districts in which they are found and in all cases it is of benefit to mining engineers to be acquainted with the main facts of the geological·history of the regions in which they have to carry on operations. Moreover, in speculating as to the origin of lodes and other deposits, we have constantly to rerer to the crumplings or the earth's crust by mountain-making movements, and to the igneous rocks which have been thrust throngh the other strata, to explain the origin or the lode fissures, and this discussion cannot be carried on without knowledge of local geology.The oldest rock yet met with in Tasmania are of Archooan age, and consist of highly crystalline quartzites and micaceous schist. They are most extensively developed towards the western side ot the island, forming a belt parallel to the West Coast from South-West Cape to Cradle fountain; but they also crop out here and there to the west and northward of this belt, where the covering strata or later age have been denuded away. Though not seen in situ in the eastern part of the colony, the abundance or pebbles derived from this formation in the conglomerates of the coal measures shows that it must in those day have formed land surfaces there also, and makes it likely that the archooan strata exist at no great depth: below many of the beds of later age now occupying the surface. Lying unconfortably upon these highly metamorphic strata we find next an extensive series of subcrystalline metamorphic conglomerates, grits, sandstones, slates, and limestones,of Cambro-Silurian age. These are well seen in the Gordou River Basin, along the West Coast Range, aloug the North Coast, and in the goldfields of the north-eastern portion of the colony. They are much broken by later intrusive rocks, and covered by younger rormations, but the series is spread more or less over the whole island.

By Creelman C. A

With the technique and data obtained in using the blast hole diamond drill for "Removal of Horizontal Level Pillar by means of Blast Hole diamond drilling at New Occidental Gold Mines N.L.," as described in Proceedings No. 133 of 1944, and a series of experiments using the blast hole diamond drill for stoping at New Occidental and New Cobar Mines over the past two years, a benching method of stoping has been developed using 2 inch coring diamond drill bits, resulting in efficient and economical ore extraction in these large ore bodies.During the experimental stages the standard H-inch blast hole was used, but the deflection of the holes, when using this solid bit, either decreased or increased the burden of the hole when it became necessary to drill holes deeper than 45 feet.It was found that after blasting vertical holes deeper than 45 feet, the ore did not break satisfactorily over the full length of the hole; on one occasion as much as 30 feet of bench was left at the bottom of the face, which had to be subsequently re-bored andblasted.As this defect was also noticeable to some extent even when the holes did not deflect, it was then obvious that the explosive had become less sensitive in the lower section of the hole. This was probably brought about by pressure being built up ahead of the detonation wave in H-inch hole, resulting in desensitization of the explosive.Another series of experiments were carried out, using 2-inch solid bits, which enabled a much greater burden on the holes, and the use of primacord for the full length of the hole.This gave satisfactory results regarding breaking and fragmentation, but was uneconomic owing to the excessive consumption of diamonds, and the slow rate of drilling.Further experiments were then carried out using 2-inch coring bits, (Fig. 1) which allowed holes of 90-feet to be bored with little deflection, and proved to be entirely satisfactory as to cost and speed of drilling.

Jan 1, 1945

By L. J. Terrill

Lateral displacement in the immediate roof beam at the Waste Isolation Pilot Plant (WIPP) is a significant factor in assessment of excavation performance for the design of ground control systems. Information on roof beam lateral displacement, expansion, fracture formation, as well as excavation convergence, is gathered using a variety of manually and remotely read instruments. Visual observations are also used when possible. This paper describes the methods used to measure lateral displacement, or offset, at the WIPP. Offset magnitudes are determined by the degree of occlusion in drillholes that intersect the offset plane. The Borehole Lateral Displacement Sensor (BLDS) was developed for installation at WIPP to monitor offset at a high degree of accuracy at a short reading frequency. Offset measurements have historically been obtained by visual estimation of borehole occlusion. Use of the BLDS will enable relationships between time dependent roof beam lateral displacement and expansion to be established in much shorter periods than is possible using visual observations. The instrument will also allow remote monitoring of roof beam displacement in areas where visual estimations are not possible. Continued monitoring of roof beam displacement, convergence, and expansion, is integral to timely and pertinent assessments of WIPP excavation performance.

Jan 1, 1996

By Maurice Bottiau

It is a quite challenging objective to aim at covering in one paper the most recent evolution in piling and deep foundations technologies. This report has to be understood within the limits of the session 2b. It will therefore concentrate on the technological evolution of deep foundation techniques, addressing design issues only when directly related to execution aspects. For the same reason, it will not address the related codes, as a separate session of this conference is specifically dedicated to this topic. Monitoring and deep excavations being covered in other sessions, they will only be addressed when clearly relevant. We will try to show, from a practical viewpoint what are the main changes and the most exciting or critical issues over the last years, as they appear from the topics addressed in the literature or in the papers published in this session of the conference. As the paper mostly intends to explain trends and critical topics, it cannot be exhaustive, neither can it give the full description of the case studies. The author invites the reader to read the full papers, for a more complete description. We have divided our report in three main topics: Piling, soil improvement and treatment and retaining walls. Anchors and tie-backs will not be treated, neither tunneling.

Jan 1, 2006

By Murray W. Hitzman

Two great revolutions in mining occurred during the 20th century. The first took place almost 100 years ago (1903-1905) with Daniel Jackling’s experiment in the economies of scale for large-scale mining at Bingham Canyon. Jackling’s ideas changed the focus of base metal exploration toward lower-grade, high-tonnage deposits. The second revolution was the impact of environmental and social concerns on mining. It started near the end of the 20th century and is still under way. This article speculates on the effects of this second revolution on the future of mineral exploration.

Jan 1, 2005

Jan 1, 1963

By A Kamkar-Rouhani

The paper describes a mineral potential mapping of gold and other base metals in Mahneshan area, Iran, using geographical information system (GIS), in which, the method of weights of evidence is used to combine spatial data obtained from different sources to make prediction for mineral potential. This is a quantitative tool for mineral resource mapping that can be used to delineate and predict favorable areas for further exploration by using the characteristics of known and similar mineral deposits. In accord with the descriptive model for gold and other base metal deposits, the spatial distribution of 20 known mineral occurrences was used. In addition, digital evidential maps were used in this study. The maps include maps of lithological units, faults and first derivative of total aeromagnetic data, remotely-sensing data of alteration and also geochemical evidential maps produced on the basis of the results of chemical analyses of samples taken from the stream sediments in the area, and analysed for Cu, Pb, Zn, Sb, As, Ag, Au, Ba and Hg elements. The binary maps were produced and then combined with the model of weights of evidence using 20 known mineral occurrences to obtain a final map of the favourable areas for further exploration of gold and other base metals in the study area. The final map is a predictive GIS model of the mineral deposits in the area. An interesting matter about the final predictive GIS model is that the faults are mainly located in favorable areas which possesses the most probability of mineralisation. Therefore, the faults in these areas have priority for further exploration of gold and others base metals.

Jan 1, 2005

By D. Harrington

This circular presents part I of a series of papers of a review of the literature on air conditioning in mines, with particular reference to the health, safety, and efficiency of miners. It deals with the physiological aspects of exposure to air contaminated by organic matter, noxious and toxic gases, and dusts that emanate from various sources in underground workings; part II will discuss the relation of abnormal mine temperatures and humidities to the health and efficiency of minors; and part III will describe theoretical and practical methods of air conditioning mines to correct or alleviate the conditions mentioned and will discuss the results attained by some of the systems now in use in various parts or the world.

Jan 1, 1938

The Golden Ridges Mine, one of the properties of New Guinea Goldfields Limited, is situated on the right bank of Nami Creek, not far from the township of Wau, in the Territory of New Guinea.The property is somewhat unique, in that the goldbearing ore-body occurs in the form of a flat seam-like deposit lying on a volcanic breccia, and covered with a mantle of overburden of decomposed porphyry. The overburden varies in thickness up to a maximum of about 65 ft.The ratio of overburden to ore is about 3 to 1. The practice developed is to strip the overburden by hydraulicking, and to mine the exposed ore under open-cut conditions, blasting to a vertical face, and using electrically operated scraper hoists for conveying the broken ore to the mill bins.The stripping of the overburden involves the boring of well-drill holes, blasting the holes and then hydraulicking the shattered material.

Jan 1, 1934

By A. C. Smith

Although only used in a few U.S. longwall mines, bleeder-less ventilation systems can be an effective spontaneous combustion control method in mines having a demonstrated history of spontaneous combustion. To provide insights for the optimization of bleederless ventilation systems for U.S. underground coal mines, a computational fluid dynamics (CFD) study was conducted to model the spontaneous heating in longwall gob areas using a bleederless ventilation system. A single longwall panel with a bleederless ventilation system was simulated, and typical longwall mine ventilation data were used in the simulations. The permeability and porosity profiles for the longwall gob were estimated using a geotechnical model and were used as inputs for the CFD modeling. The effects of gob permeability and resistance of the collapsed entries on the spontaneous heating were studied. The effectiveness of using nitrogen injection to prevent spontaneous heating in the gob was also examined.1

Jan 1, 2008

By Roger S. Jackson

"This study interprets vibrations produced by single underground shots, recorded on surface by 135 digital seismographs laid out in four linear arrays. Several vibration anomalies were observed and are investigated. A novel method of displaying the blast-induced vibration iso-contour data relative to the three-dimensional representations of the geological rock units and structures leads to the following interpretations:• The identified faults commonly dampen or amplify vibrations, on the evidence of the peak particle velocity,• Strong anisotropy of geologic formations produces different vibration attenuation in the various directions of interest,• Low-vibration “depressions” can be related to the presence of faults, and• Higher vibration levels than expected based on ‘scaled-distance’ principles are observed close to intersecting faults.The interpretations from this study document a better understanding of the geotechnical influences on blast induced stress wave propagation in a geologically complex area. The practical benefit of this understanding is better control of surface vibrations, experienced from underground mining activities."

Jan 1, 2010

By R Handfield, G Kary, Frieda Project

Recent exploration by the Cyprus Amax-Highlands Pacific-OMRD Joint Venture at the Frieda River project, PNG has demonstrated the extent of igneous phases, alteration and mineralisation, and the relationships between the various mineralisation styles in this major Cu-Au porphyry-epithermal system. The project area is in the obducted volcano-sedimentary section of the New Guinea mobile belt 78 km NE of Ok Tedi. It is between two major NNE dipping faults interpreted to have undergone thrusting then sinistral shear in the Late Miocene to Recent. The Frieda River Igneous Complex is a 15 km +7 km ovoid area with a central pod of basaltic andesite volcanics with cogenetic diorite to quartz diorite subvolcanic intrusions, and flanking clastic sediments. A series of late-stage, hornblende quartz diorite plugs ring the main igneous mass. The igneous rocks have a normal K calc-alkaline character with a very limited compositional variation. The intrusives are exposed on the eastern flank of the complex and have five mappable units and numerous defined phases. The southeastern quarter of the complex is host to a cluster of at least seven stockwork porphyry copper and skarn-hosted deposits within an area of 4.5 +3.5 km. The Horse-Ivaal and Koki deposits have identified resources totalling 804 mt @ 0.46 per cent Cu and 0.3 ppm Au, and the other deposits are in various stages of exploration. All these deposits are related to the Horse Microdiorite phase of the Complex and are outlined by a zone of potassic-propylitic-SCC alteration. Local overprinting argillic and advanced argillic alteration is related to a separate, post-porphyry mineralisation intrusive phase. The recent emphasis has been on the identification of higher-grade zones using ideas of structural control and specific intrusive-alteration-mineralisation relationships within the known resource areas. An elongate area 13 km x 4 km in the centre of the Complex has advanced argillic alteration in the volcanic rocks. This alteration zone hosts the Nena deposit (52.8 mt @ two per cent Cu and 0.7 ppm Au) and approximately 20 prospects of high sulphidation type. These deposits are distributed along two prominent NW-trending siliceous ridges interpreted as regional scale structures. Nena is a pod of vein and replacement sulphides hosted in a tectonically controlled multiphase breccia that overprints the advanced argillic alteration. The Nena deposit is 4 km from the nearest of the major porphyry occurrences. It is underlain by basemetal veins and minor porphyry mineralisation that are related to the Flimtem Trachyandesite intrusive phase. The recent search for additional Nena-type ore has focussed on the siliceous ridges using detailed structural and geochemical ore control criteria. Widespread, but poorly mineralised, basemetal-bearing carbonate and sulphate veins form a ring around the mineralised area. These veins have sericitic selvages, cut the porphyry mineralisation, but are cut by and locally underlie the silica-alunite phase of the advanced argillic alteration. The current model is that there are discrete intrusive phases responsible for each of major hydrothermal events at Frieda. These include from oldest to youngest:the Koki phase has no related alteration or mineralisation; the dominant Frieda phase has the hornfels, early skarn and minor magnetite-chalcopyrite mineralisation; the Horse phase has the bulk of porphyry copper and skarn-hosted mineralisation and minor basemetal veins; the peripheral Knob phase is barren; and the Flimtem phase has the high sulphidation epithermal deposits and minor porphyry and vein mineralisation. The intrusive phases span the interval 17 to 11.5 Ma and are co-magmatic. They represent discrete batches off the parent magma, rather than simple fractionation products.

Jan 1, 1999

By V. A. Cammarota

In this report, the effects of anode-production variables, such as aggregate coke sizes, pitch binder content, and baking cycle, were investigated. A small alumina reduction cell proved effective in evaluating anodes prepared from commercial materials and from lignite coke and pitch. Compressive strength was found to be the physical property most significantly influenced, but it did not appear to affect anode consumption. Specific carbon consumption, that is, the ratio of carbon in the anodic gas to carbon theoretically oxidized at the anode, was used as an index of anode consumption. It was found that an anode made with lignite coke and commercial pitch was very low in consumption; however, anodes made completely from lignite but by a different fabrication method showed high consumption and anode deterioration. Microscopic examination of anodes after electrolysis showed evidence of higher consumption at low current densities, and was useful in judging overall anode quality. Based on the physical properties of the anodes and their consumption during electrolysis, lignite can be a suitable material for anodes, provided the proper fabrication conditions are used.

Jan 1, 1970

By Woodcock J. T

When an aqueous suspension of pyrite and a manganese ore reacts with oxygen, manganese is dissolved by the ferrous sulphate and sulphuric acid produced in situ by oxidation of pyrite. In the absence of added acid, the optimum conditions are: a molecularratio of Mn02/FeS2 of about 1·0, a temperature of about 1400 C., and an oxygen pressure between 25 and 90 lb./sq. in. Under these conditions, complete extraction of manganese is obtained in six hours leaching. An addition of sulphuric acid enables an Mn02/FeS2 ratio of 2·0 to be used successfully.Manganous sulphate decreases in solubility with increase in temperature above 1000 C., but even when the solubility limit is reached during leaching, reaction to form MnS04 still proceeds, and on cooling the MnS04 redissolves.INTRODUCTIONMany manganese deposits contain secondary manganese oxide minerals which are difficult to concentrate. Considerable attention has therefore been given to their hydrometallurgical treatment. In most manganese oxide minerals, the manganese is quadrivalent and must be reduced to the divalent state for dissolution. Reduction and dissolution can be accomplished in a number of ways, one method being to use aqueous ferrous sulphate solutions.A possible source of ferrous sulphate is pyrite as it is known that ferrous ion is an intermediate product in the aqueous oxidation of pyrite. It was therefore thought possible, that by heating an aqueous suspension of manganese oxide and pyrite with oxygen, the ferrous sulphate and sulphuric acid formed from pyrite would provide the necessary leaching reagents for manganese in situ. There are certain advantages in producing ferrous ion in situ...

Jan 1, 1958

By Y. L. Sun

The feasibility of using the ultrasonic wave attenuation method for measuring in-situ stress is examined theoretically and experimentally. The theoretical analyses show that for a given rock type the relation between stress and attenuation coefficient ratio can be approximated closely by second-order polynomials. Combining the elastic and statistical theories, the magnitude and direction of the existing principal stresses can be predicted by using the relations between stress and attenuation coefficient ratio obtained in the calibration of core specimens. Several experiments are conducted in the laboratory on two types of rock. The experimental study consists of two parts: the attenuation-coefficient measurements in core specimens under uniaxial stress and the attenuation coefficient measurements in boreholes drilled through blocks of sandstone and limestone subjected to uniaxial compressional stress. Compressional waves are used exclusively in the measurements.

Jan 1, 1989

By P. K. Leung, S. R. Allada, P. M. Dranchuk, D. Quon

The alternating direction explicit procedure (ADEP) makes use of the boundary conditions to reduce multi-dimensional problems to a series of one-dimensional problems. The method, previously applied to reservoirs containing only an under-saturated oil, has now been extended to cover the case of natural gas reservoirs. l his involves solving a non-linear partial differential equation, application of the procedure is straightforward and no calcuIational problems were encountered. INTRODUCTION There has been a growing interest in formulating mathematical models of petroleum and natural gas reservoirs — models which permit the engineer to examine and evaluate the physical and economic consequences of various alternative production policies. The tremendous reduction in the cost of solving such models in recent years has made possible their use as an almost routine management tool. This reduction is the result not only of improved computer hardware but also of the development of more efficient mathematical techniques. The present paper is concerned with the application of a recently proposed numerical method (ADEP) to two-dimensional gas reservoirs. STATEMENT OF THE PROBLEM Given a two-dimensional Region R, bounded by a closed Curve C (Fig. 1) such that the behavior on Curve C is known, the differential mass balance for each fluid phase in R, neglecting gravitational effects and assuming Darcy's law for fluid transport, can be written as:

Jan 1, 1967

By H. Ikeda

INTRODUCTION [Slide 1] The Role of the MMAJ Ladies & Gentlemen, it is a pleasure for me to be able to make a speech at this SME annual meeting, representing the Metal Mining Agency of Japan. [Slide 2] Today’s Topics In my presentation today, I would like to divide my topics into four parts. First of all, I would like to describe the current situation of Japanese non-ferrous metal mining and mineral processing industries in Japan. Secondly, the supply and demand of non-ferrous metals in Japan. Thirdly, I would like to spare some minutes on the overview of overseas development by Japanese mining companies. Finally, since some people may not be sure what the Metal Mining Agency is or what this Agency, I would like to briefly introduce the Metal Mining Agency of Japan.

Jan 1, 2001

By Xiao Caimei

The method of Substance Flow Analysis (SFA) provides a helpful tool for the study of the industrial metabolism of a certain metal within a regional level, such as copper, lead etc. In this paper the flows and inventory of cobalt in China, 2008, were traced with the STAF model, and the situations of production, fabrication and manufacturing, use and waste management in China were introduced. The result revealed that the resource of cobalt in China was so poor that a large amount of cobalt material or cobalt products needed to be imported, and there was lack of recycling of cobalt resources.0

Jan 1, 2010