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Research on Universal Depressant of Talc and Serpentine

Sep 13, 2010

As the theme of the conference is ære-discover Otago' from the minerals point of view, it is also timely. Of the eight million ounces of gold recorded produced from Otago, perhaps a quarter of this came from the goldfields of St Bathans, Vinegar Hill and Cambrians. The most notable among them was the Kildare Hill Mine, which is the so-called Blue Lake at St Bathans today. The bottom wash encountered in this mine contained the famous Kildare lead, which averaged 7 1/2 dwt to the dish, and is still one of the richest leads of alluvial gold known in the world. The richness of this lead, the best encountered in these gold fields, is otherwise stated to have yielded more than 42 ounces of gold to the cubic yard. It should be borne in mind that this equates to about $22 000 per cubic metre, in todayÆs values. I have been told by older residents of this district that in fact about 1 million ounces came out of the Kildare mine and associated workings. In todayÆs values, this would be about 530 million dollars worth of gold. The largest mines in the district were at Surface Hill, Kildare Hill, Nicholsons, Vinegar Hill, the Never Fail claim at Shepherds Flat nearby, and at Cambrians. It would appear that in almost every case, work stopped when the bottom wash progressed too deep down dip of the anticline hills on which it was initially found. The mining methods were sluicing and hydraulic elevating, and although the gold bearing ground did not stop, eventually it exceeded the ability of the mining methods then available years ago, to work it further. When it is realised that the previous mining has removed what is likely to be only a low percentage of the gold resources in these fields, a tantalising situation presents itself today in that mining technology now available will enable another cut to be taken off these fields. As in the past, I believe this will be million ounce plus and multi-million dollar scenarios, where the economic and social benefits will become widespread prizes.

Jan 1, 1992

About twelve months ago, owing to the increasing quantity of stone and dirt being drawn frQm the Victorian State Coal Mine due to the large amount of dead work below ground, cutting, faults, etc, and to the increasing quan#ty of banded coal beingworked, the writer was forced to consider the question of economy in handling the spoil at the surface. The method in operation at the time was to run out level dumps fro,m the, tipping floor of the heapstead, or brace, and to tip most of the skips of stone in tipplers at the ends of the dumps, the remainder of the skips being side-tipped to widen the dumps.The method, whilst quite satisfactory for dealing with a few skips of stone, was found to be costly as the dumps extended, and the number of skips to be dealt with increased from 300. to 400 per day of two shifts;. therefore, in order to expedite thework and cheapen its cost, the writer devised an improved method which may be qescribed as follows :-(1) The stone is tipped into a hopper car which holds about 10 skips(2) The hopper car is hauled up an inclined dump by means of an electric winch.(3) The spoil is dumped from the car forwards or to either side, as required.(4) The car is returned to the starting point for a further load.Plate I Fig. 1 gives an idea of the construction of the hopper car. In the illustration the car is in position for tipping to one side. The body of the car is supported on a ball race on the under carriage, and it can be swung round to tip in any required direction. The bottom of the hopper is extended to form a 4 ft. lip...

Jan 1, 1918

By S M. Aminossadati, R Bagherpour, F Hasheminasab

Mine ventilation is an essential part of underground mining operations used to provide fresh and cool air, as well as to dilute and remove contaminants from the work environment. This paper presents an overview of the ventilation and gas management systems in one of the underground coalmines in Iran: Parvadeh_1 mine. The mine is located in the Tabas coalfield in the South Khorasan province. It is the only fully mechanised mine in Iran utilising the longwall retreat technique. The mine produces 1.1 to 1.3 Mt of coking coal annually. The mine ventilation system currently utilises two 630 kW exhaust surface fans. The gas management system includes surface to in seam (SIS) predrainage boreholes. The underground mine is equipped with an underground gas reticulation pipeline that is connected to a surface plant for the production of methane gas. This study shows that the ventilation and gas management systems of the Parvadeh_1 mine are in line with the standards of Australian underground mines.CITATION:Hasheminasab, F, Aminossadati, S M and Bagherpour, R, 2017. An overview of ventilation and gas management systems in an underground coalmine in Iran, in Proceedings Australian Mine Vent Conference 2017, pp 41–46 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By L. Obert, D. E. Stephenson

The objectives of this investigation were to develop a laboratory procedure in which core discing could be produced under known (and variable) stress conditions, and to study the discing characteristics of several fypes of rock. Discing of rock cores refers to the formation of discs or wafers of relatively uniform thickness which fracture or rupture on surfaces approximately *Fracture is a type of failure in which there is a complete loss of cohesion and fresh surfaces are created. Rupture is a type of failure in which there Is only a partial loss of cohesion. normal to the axis to the core (see Fig. 1). Usually the surfaces of the discs are concave-convex with the concave side toward the collar of the hole. The surface of the fractured discs are like those created by a tension failure (or possibly a shear failure with virtually no normal compressive stress). This phenomenon has been observed by a number of investigators1-5 in the course of diamond drilling in underground mines, especially in areas suspected of being under high stress. The state of stress in the core required to produce discing is not exactly known. Tranter and craggs6 theoretically investigated the stress distribution in an infinite cylinder, subjected to hydrostatic pressure, minus p, from z = 0 to z = 8 and unloaded from z = 0 to z = 8, Fig. 2. The exact solution to this problem shows that a tensile stress develops in the loaded region near z = 0 with the greatest tensile stress on the axis of the cylinder. A tensile stress also developed on the surface of the cylinder at a point just outside of the loaded zone. Jaeger and Cook3 experimentally investigated the discing mechanism by biaxially loading cores in a pressure jacket sealed at the ends by O-rings. According to the Tranter and Craggs theory it would be expected that failure should occur at the pressure discontinuity at the O-rings. The experimental results showed that if the specimen was unjacketed it broke at random points within the pressurized zone and at a pressure somewhat greater than the tensile strength of the specimen, presumably due to the development of a

Jan 1, 1965

By John G. Henning

The Porcupine Joint Venture operates the Dome Mine in South Porcupine, Ontario. Dome underground began production in 1910. It is the longest continuous operating gold mine in Canada, producing in excess of 15 M ounces. More than 900 underground stopes have been mined and hundreds of miles of drifts, sublevels and raises developed. Underground mining methods included shrinkage, cut and fill and longhole. Not all stopes were backfilled upon completion, particularly the longhole stopes. The Dome open pit was designed above the underground mine workings such that, as the pit is excavated, it intersects underground drifts and stopes. Potential operational problems associated with the interactions between the stopes and the pit walls may occur, necessitating pit wall redesign, ground support installation and operational rescheduling. Each intersection of the pit with the underground mine workings is closely evaluated to maintain a safe working environment and wall stability. This paper discussed how risks to pit wall stability are assessed, mitigated and monitored.

May 1, 2004

For the purposes of this discussion it is assumed that contributors should express the thoughts that arise from their personal experience. So wide is the range of mineral deposits, and so varied the methods employed in their discovery and development, that no two geologists are likely to have been impressed with the same applications of their science. The author's own personal experience has been, during recent years at least, very largely concerned with the broader aspects of the employment of scientific method and geological knowledge to the problems of exploration and exploitation, for the guidance of the general public and governmental authority rather than of mine executives and directors. The view-point thus reached is likely to differ in many respects from that of men who are much more intimately concerned with the mining problems of a single metal or a single mining field, and for this reason a statement may perhaps supplement those from others whose experience has been markedly different.It may well happen that, at some not distant date in the future, when systematic and comprehensive instruction in economic geology is embodied in the courses- prescribed for mining engineers during their years of training, the author's comments will be quitesuperfluous; but at the present time they appear to him to call for expression.The Need for Training of Mining Men in Economic Geology.Contact over a period of many years with mining men who have had different kinds of training and experience has been convincing that there is a general reluctance to acquire a full rational understanding of the geological factors involved in exploratory and developmental problems. The correction of this attitude is regarded as vital to the industry and it is necessary to insist that the outstanding requirement of the present day is the utilization of all branches of geological, investigation in the field and the laboratoryby men who have had systematic and specialized training in these matters. The science of geology is many-sided, but is, nevertheless, whole and essentially indivisible. No one can afford to disregard any fraction of its content 'or any of its methods of investigation.The greatest advances have been made in the understarnding of the occurrence of mineral deposits by those whose knowledge Qfbasal principles, has been soundest, whose endeavour has been to ascertain all their relationships in space and time, whose attention to detail of all kinds has been keenest, and at the same time, whose capability to distinguish between major and minor features has been most marked.With the passage of the years and the accumulation of data from many lands, it has been possible to build up a great body of information regarding the primary deposition and secondary alteration of mineral occurrences, which is of the utmost value in guiding thesearch for new deposits to take the place of those that become exhausted. This heritage is due not only to the efforts of gifted in...

Jan 1, 1950

The Development of a Non-Roasting Technology for Polymetallic Gold and Silver-Bearing Sulfide Concentrates Treatment

Sep 13, 2010

Bioleaching Metals from Waste Printed Circuit Boards and the Shapes of Microorganisms

Sep 13, 2010

Despite the media's use of the mining industry as a whipping boy over its perceived attitude towards the environment, the facts remain that the only legislated requirement in the SA Statute Books for any form of environmental impact-assessment prior to development is to be found in the Minerals Act in the form of an EMPR. Not only is our industry complying with this requirement, but moves are afoot to set up environmental management systems for existing operations in preparation for seeking accreditation under ISO 14001 when published towards the end of this year. On how broad a front are we advancing? ? Is the industry equipped to handle these challenges? ? Does it have the determination to overcome its problems? ? Do we realise that failure may mean the loss of markets overseas to competitors who can meet the international standards? ? Where are the shortcomings and when must our efforts be focussed?

Jan 1, 1996

By C. E. Van Orstrand

An intrusive body is a mass of igneous rock that has migrated upward, presumably from great depths. Great variations in form, composition and depth of burial occur. It is not proposed in this paper to go into all of the details of the problem. Instead, it mill be assumed here that the intrusive has the form and characteristics represented in Fig. I. According to W. 11. Emmons minerals are not deposited in appreciable quantities below the "dead line." Important amounts of ores of virtually all metals may be found around summit cupolas, but only gold, copper and zinc (in limited quantities) are usually associated with trough cupolas. Most students of ore deposits agree that temperature changes are largely instrumental in precipitating many ores in the "hood" and that the difference in temperature between the intrusive and that of the country rock may be the chief factor in determining the mineralogy of a deposit. A problem then of some interest is to correlate the principal physical features of the intrusive with the phenomena of heat conduction as evidenced by the cooling curves and the isothermal surfaces. Mathematical Theory In order to show the possible application of heat conduction to the interpretation of the processes of metalliferous deposition associated with intrusives, it will be as- sumed that the intrusive is a large par-allelopiped of dimensions, 2l, 2m, 2n. The equation that represents the flow of heat from the parallelopiped into country rock (v = o, 1 = o), which has the same thermal properties as the intrusive, is2,3 l-x v I FT 2 [2 2 — l-x m — y — m — y n — z In this equation, the origin, x = o, y = o, z = o, is at the center of the parallelopiped. v = temperature at point x, y, z, time 1. v, = initial temperature throughout the intrusive, 1 = o. k = coefficient of thermal diffusivity. a, ß, y are variables of integration. Put n = m in Eq. I, and we have v I [2/5 [2I-x 2 — l-x m — y 2 2 2 kt 2 20xt e-a2da ebrdß

Jan 1, 1946

This paper is a collection of thoughts and frameworks. It addresses a simple question: æIf we are to believe the large number of people and institutions indicating that humans are destroying the Earth and that the end is nigh, why do we bother trying to be sustainable?Æ The paper lays out evidence for the existence of multiple hazards to global society. The existence of a hazard alone is insufficient to make an assessment of risk. Risk estimates are required to support decision-making. An approach to assessing risk is provided and some limited data are presented. A new ædefinitionÆ or statement of what sustainability (in a broad sense) might have become is then given. A decision framework for guiding decision- making about the risks is developed. This framework includes a definition of leadership with inherent implications for what determines whether a leadership position by title is actually leading. The paper concludes by offering a view of minerals industry sustainability and considerations around maturity in the current economic situation. It is hoped that by placing this collection of frameworks around sustainability, a supporting structure emerges that will facilitate action. It is proposed that action taken in this way will be more effective than reaction to regulation or even social license to operate imperatives because it is driven by a more holistic view of the challenges and the potential roles of individuals û all of whom are potential leaders at some scale of action.

Jan 1, 2009

By Yongbin Yang

Cathodic reduction of oxygen is a process involved in many fields. As is well known, the mechanism of oxygen reduction usually varies considerably with electrode substrates. In this paper, cathodic reduction of oxygen on gold electrode was studied by linear sweep voltammetry with regards to cyanide leaching of gold. As the results shows, the electron transfer number increases as potential shifted negatively and decreases as pH value increases. Besides, the increment of electron transfer number as a function of potential decreases when pH value increases. When pH increases to 13.0, the volt-ampere curve exhibits a relative flat section with currents approximate to the limit current density of a 2e process. By varying dissolved oxygen concentration, the electron transfer number was calculated for pH11.0 at different potentials, the results being 2.387e, 2.732e, 2.982e, and 3.227e at, -0.35V, -0.40V, -0.45V, and 0.50V, respectively. The calculated current densities are in good conformity with measured results.

Jan 1, 2010

By A. Lyndon

Vertical and lateral load tests were carried out on two 13 m deep bored cast-in-place instrumented piles, socketed into weathered sandstone. The first pile, 1200 mm in diameter, was loaded vertically to a maximum of 16000 kN and then loaded to failure under lateral load (1900 kN). The second pile, 1500 mm in diameter, was tested under lateral load up to a maximum of 2400 kN. It was found that the deflections of the 1200 mm pile were more than twice those of the 1500 mm pile under similar loads. The soils on the site are not easily tested in the laboratory, or by conventional insitu site investigation techniques, parameters needed in design can only be reliably obtained from pile test results. In this report shear moduli are back analysed from the vertical load test and the two lateral load tests. For these similarly installed piles very different design parameters were determined from the lateral load tests, the only known major difference between the piles being that the 1200 mm pile was loaded vertically before it was loaded laterally. Changes in G values needed to match performance under vertical load if applicable to lateral loading could have accounted for a significant amount of the difference.

Jan 1, 1989

By Thomas Barkley

Recent developments in hardware and software have made accurate measurement of Underground Face (Development) Drilling a reality. New and compact laser profiling equipment makes it possible to measure drilled material left on the face as well as the actual tracks of the holes drilled in the rounds. Utilization of these available technologies makes it possible to correctly define the drilling accuracy and the blasting pull. Through the use of actual face round measurements, I will show the level of definition and amount of information that can be collected.

Jan 1, 2003

By David R. Skuse, Jacek A. Kostuch, Steven M. Fortier

"Particulate ground calcium carbonate (GCC) is used as a filler and coating pigment in a wide range of applications including papers, paints, plastics and films. In this paper we will overview the requirements for GCC used in both filling and coating applications in the paper industry and highlight the processes used in the production of these materials.INTRODUCTIONCalcium carbonate is both abundant and very widely distributed occurring most commonly as limestone, marble and chalk (Harben 2002). Given, the high purity, whiteness and relative inertness of these materials it is not surprising that they are heavily utilised in a range of industrial applications. Worldwide ground calcium carbonate (GCC) capacity is estimated at 50.5 million tonnes per year (Roskill, 2002). This usage is divided between relatively coarse materials that are used in applications such as landscaping, cultured marble and carpet backing and finer grades that find application in plastics, rubbers, inks, paints and paper. Given the usage of calcium carbonate products across a very wide range of consumer products, the outlook for GCC is very promising with growth expected in many markets. Growth is anticipated across many applications in the emerging nations and more specifically in paper applications on a global basis.Over the last several decades the GCC processing industry has evolved to be well adapted to both the cost effective production and delivery of standard products and the production of high performance speciality products. Many of the standard unit operations found in the metaliferous raw material processing industry are also used, albeit in some cases in modified form, in the processing of GCC. Coarse products (diameter > 3 - 10 µm) are typically produced by dry processing routes. Whereas, the finer products are typically produced by a combination of wet and dry processing."

Jan 1, 2004

The Application of Roasting Pretreatment for Antimonial Refractory Gold and Silver Ores

Sep 13, 2010

By R. Unger, L. Mallett

The use of virtual reality (VR) technologies to train miners is an evolving area in research and development. In July 2006, representatives of 14 international organizations met to discuss current VR-related efforts and explore ways to employ VR in the future. This paper gives an overview of the various approaches presented at the meeting and discusses directions for future implementation. An example of a training package that teaches mine map-reading skills is presented. The meeting was the first step to building collaborations for furthering VR applications for mining. Planning has begun for a 2008 meeting open to broader participation.

Jan 1, 2007

Adsorption of Starch on Kaolinite Surfaces

Sep 13, 2010

By Paul Swatkowski

A Note About Copyrighted Material ??Permission to Use? has been granted ?Teachthe7habits ?Think win/win (4thHabit) ?Don?t stop here ?i.e., buy the book

Jan 1, 2009