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By Callcott R

Prediction of raw coal size distributions and those generated by processing are examined using spreadsheets and the matrix analysis of breakage processes. Run of mine coal size distributions are predicted from the lithotype properties using a

Jan 1, 1998

Viking Holdings Ltd, a Todd Corporation company, is active in the mineral industry through operations, joint ventures and equity investments. Identification and management of risk is key to the success of the company. This paper discusses risk in general terms and in the context of Vikings activities. Reference is made to the current environment and the impact of risk and environment on profitability.

Jan 1, 1997

By Osborne V. J, Urbank W

An explosion occurred at Moura No. 4 underground coal mine in Queensland on 16 July 1986 and resulted in the loss of 12 lives. The official report of the accident concluded that the most likely source of ignition was the flame safety lamp. This paper describes an investigation of the behaviour of a flame safety lamp, similar to the one involved in the Moura explosion in atmospheres of methane, coal dust and air, carried out at the Queensland Department of Mines . Testing and Research Station. The behaviour of the lamp is described in conditions of varying methane and coal dust concentrations in air, and varying air velocity. Particular emphasis is given to the 'phenomenon of burning which occurs inside the gauze and which is capable of causing the ignition of an external explosive atmosphere.

Jan 1, 1988

By Booth GW, Robertson IG

The Paddington Gold Mine ties within the Norseman-Wiluna greenstone belt, in the celebrated Eastern Goldfields province of the Yilgarn Block, Western Australia. Regionally, tropical to subtropical weathering has effected development of a prominent regolith and a deep lateritic profile. Detailed examination of the clay mineralogy, largely from a single drill hole which traversed the original Paddington I deposit, outlined three separate, vertically gradational assemblages, which are, in part, rock-type dependant. These include; 1. kaolinite with minur to trace quantities of sericite/illite (0-22m), 2. smectite and/or interstratified clay minerals, together with variable amounts of kaolinite, relic chlorite and illite/sericite (22-81m), and 3. chlorite and sericite (> 81m). Near surface, kaolinitic assemblages may be directly correlated with the intensity of lateritization, whereas smectite and interstratified clays from intermediate zones appear in association

Jan 1, 1989

The safety of mine winder systems with regard to overwind, underwind, rope factors of safety, winder brakes and the like is discussed. Many misunderstandings and poten- tially unsafe practices are discussed as well as variations between requirements of various Mines Departments. Various methods to improve safety are suggested and the formation of an industry committee to review present practice and foster development of improved safety and economy is also suggested.

Jan 1, 1984

By Noreen D

At Bougainville Copper Limited comparison testwork was conducted between "horizontal" cycloning and conventional vertical cycloning. Horizontal cycloning reduces circulating load and allows increased ball mill throughput. Cyclone efficiency is the same or better as a result of the reduction of fines short-circuiting to the underflow. Operationally, horizontal cyclones are less likely to suffer from blocked spigots and high cyclone feed pump sump levels. Cyclone feed pumping power is reduced. High horizontal cyclone underflow density provides the option to optimise grind by manipulating water addition to the ball mill feed.

Jan 1, 1988

By Bennet A. G

As part of the construction of the Melbourne Underground Rail Loop it was necessary to construct two 7 metre diameter tunnels, each 100 metres in length, by shield driven excavation through an alluvial valley at Elizabeth Street. The tunnels had a primary support of bolted precast reinforced concrete liner blocks and were excavated with the aid of compressed air. The work was undertaken by the Tunnelling Group of the Melbourne and Metropolitan Board of Works as nominated sub-contractor to John Holland (Constructions) Pty. Ltd. The paper describes some of the problems associated with the construction of the above tunnels and the methods used to overcome them. In particular

Jan 1, 1981

By Amelunxen R, Finch JA

Flotation columns represent an important addition to flotation practice. Columns have largely replaced. conventional machines in molybdenum cleaning in Canada. Columns have been successfully tested on bulk copper/molybdenum cleaning at Gibraltar Mines Ltd. A rougher cleaner/scavenger cleanercombination was shown to be capable of giving higher grades and recoveries compared with three stages of conventional cleaning. A control strategy for the columns has been developed. An interaction between gas hgldup and wash water rate has been exploited to control performance.

Jan 1, 1985

By R Linares

The efficient operation of any modern metallurgical facility depends on the accurate measurement and estimation of flow rates, inventories, and composition of their intermediate and final products. All of this information is subject to both statistical errors and gross errors, which can lead to poor estimation of efficiency, yields and specific energy consumption. The detection and the elimination of these errors require not only plant data, but also product transactions and the operational events. Once the gross errors have been eliminated, it is possible to estimate validated performance indicators, such as grade recovery or yields. This paper describes the methodology to implement a unification and gross error detection system using the available infrastructure of both information and data reconciliation system. It covers the different infrastructure layers, from the data collection layer to the data validation and reconciliation layer. In addition, the impact of these methodologies on the decision-making process is presented.

Jan 1, 2005

Consideration is given to the factors affecting raceway activity and the hearth design of a zinc-lead blast furnace. Results of measurements made on operating furnaces are given and comparisons are made with published data both from operating iron blast furnaces and from dynamic models of the zinc-lead blast furnace. Indication is given of the methods used for assembly of the relevant information into the specification of a commercial furnace design. A discussion on the comparative merits of furnaces of circular and essentially rectangular plan is given based on the concepts explained in the paper.

Jan 1, 1981

IN the present paper it is the writer's intention to largely confine the subject-matter to details relating to the metallurgical practice in connection W,ith the blast roasting of lead ores at the Port PiJ;ie works of the Broken Hill Associated Smelters Pty. Ltd. rather than to elaborate on mechanical plant details which are more or less standard equipment of the average Dwight and Lloyd or Huntington-Heberlein blast roasting installations (hereinafter referred to in the text as D. & L. and I.I. & H. respectively). The present blast roasting plant is a combination ot D. & L. straight line machines and IQ-ton H. & H. pots. The latter installation was an operating unit prior to the introduction of the D. & L. machines, the pre-roasting then being accomplished in Ropp roasting furnaces.On the introduction of the D. & L. machines the use of the Ropp roasting furnaces as a pre-roasting unit was discontinued, and this step of the process was then carried out on one section of the D. & L. installation.Consequently, then, the present plant consists of (1) A section of D. & L. machines, which operate solely as a pre-roastiIig unit. (2) A section of D. & L. machines which operate to their full capacity as 3, final roasting unit and treat the main portion of the pre-roasted material.

Jan 1, 1922

By Showers JAF

The Western Mining Corporation mining lease on the Bendigo Goldfield measures 5krri x 18km with more than 20 anticlinal folds parallelling th long north-south boundaries. Numerous closely spaced shafts and extensive underground workings on the reef lines along the folds flooded with groundwater following the progressive abandonment of the field. Preliminary water sampling and assessment demonstrated that a major dewatering programme and acceptable disposal methods were necessary to dewater interconnected old workings in areas of interest prior to any underground work taking place. A field wide geohydolic investigation was undertaken to establish geohydraulic parameters, groundwater recharge rates and water qualities. Data from the field investigation together with estimates of the volume geometry of the submerged workings as obtained from old mine plans, production history, and limited pump testing results were used with an appropriate analytical model to obtain estimates of water discharge rates required to reach various dewatering targets. Water disposal options were limited by relatively high salinities, arsenic levels, contained hydrogen sulphide, and the mine locations within the urban areas surrounding Bendigo. Direct disposal to the surface drainage system could not be considered, treatment to acceptable discharge standards was not economically feasible, and it was necessary to adopt a strategy of collection, containment, and evaporation.

Jan 1, 1988

Magneto flotation is a recently developed method aimed at simultaneous utilisation of the magnetic and flotation properties of minerals in separation processes. In this method, magnetic minerals are prevented from reporting to the froth product while non-magnetic minerals are being floated. With suitable ores, this makes it possible to reduce or entirely eliminate the cleaning and scavenging operations that are otherwise necessary in conventional flotation and magnetic separation systems. This paper describes the testing of magneto flotation on a Canadian magnetite ore. The ore sample used in the experimental work contained a total of 32.89 per cent Fe of which 87.60 per cent was magnetic in the form of magnetite. Magnetoflotation yielded, in a single step, a final concentrate assaying 69.10 per cent Fe and with an overall recovery of 84.84 per cent representing a magnetic iron recovery of 96.39 per cent. Comprehensive comparisons were made with conventional magnetic separation and flotation, and it was found that with these methods at least four processing steps were required to achieve results similar to those obtained with single-stage Magnetoflotation.

Jan 1, 1993

By Anderson JDC

Opencast Lignite Mining requires topwall strata of seams to be fully depleted and footwall aquifers sufficiently depressurized. To prevent a spread of the cone of depression into protected wetlands some distance away, alternatives had been investigated such as closing water works, underground slurry wall barriers and recharge by infiltration. As a result of these investigations, the infiltration method has been chosen and in a first phase during the next decade it will utilize as much as 55 x 106 m3/year. Using this approach, the survival of the wet lands is assured.

Jan 1, 1988

The Jurassic Walloon Coal Measures crop out over much of the Moreton Basin and contain numerous thin, banded coal seams which have been mined at various locations since the 1870s. Historically most mining has been by underground methods. Increased exploration during the 1970s and 1980s has led to the delineation of significant open cut coal resources and to the development of the Oakleigh, Jeebropillly and Ebenezer open cut coal mines in the Rosewood-Walloon area. Over 2 170 million tonnes in-situ of shallow, high volatile bituminous coal with a mean maximum vitrinite reflectance of between 0.5 and 0.6 have been proven in the Basin.

Jan 1, 1991

By Poplawski R. F

A 32-channel PSS seismic monitoring system was commissioned at Mt Charlotte mine in 1994, and at the time it was the first such system in Australian mines. The system continuously observes the occurrence of seismic events and locates them accurately in space and time. Mt Charlotte has a history of seismicity, with the largest event in recent years of Richter magnitude 4.3. The decision to 'go seismic' was made despite some uncertainty regarding its potential usefulness. However after the first year of operation, benefits have been realised in terms of less production downtime, improved mine safety and mine planning, and better understanding of the nature of Mt Charlotte seismicity. The seismic network has performed well, recording 550 events in its first year of operation to a location accuracy averaging ¦ 12 metres. System reliability is excellent, with very little downtime, and acceptable operation and maintenance times and costs. Observations show major distinct changes in the rate of mining induced seismicity over time periods of weeks and months. Events have tended to cluster in specific mine areas and on particular faults and structures. Case examples of pillar preconditioning, breakout around an orepass, and a major stope rockburst, illustrate the role of seismic data and the benefits it brings to safety, productivity and planning.

Jan 1, 1995

By Spencer GA, Saul SJ

The flight line spacing in low level aeromagnetic surveys is the principal factor governing both the cost and the amount of geological detail which can be extracted from the data. The rate at which geological resolution diminishes with wider line spacing is illustrated by progressive subsampling of a 200 m spaced data set from the Charters Towers region in Queensland.The usefulness of high frequency type filters in enhancing shallow structural features is seen to be limited to the 200 m data.It is concluded that each data set is suited to a particular scale and style of geological investigation with only the 200 m data having sufficient detail to identify the subtle structural patterns which are crucial to mineral exploration.

Jan 1, 1976

By Goode RA

It is-assumed that a pipeline system is economically justified as a means of transportation.. The terms "True Life" and "Economic Design Life" are defined. The most usual design alternatives to be considered from both physical and economic -viewpoints are listed and a summary is given of the main factors to be costed in assessing the relative economics of each alternative. A brief statement of the recor mended method af economic. assessment is given and an example is included. The paper aims to present a reasonably accurate, simple and practical method of considering the main economic factors which govern design.

Jan 1, 1962

The mined-out Old Waite volcanogenic Cu-Zn deposit lies in the Noranda mining district of northwestern Quebec. The deposit has a distinctive pipe-like zone of alteration beneath the massive ore, extending into the stratigraphic footwall. The hydrothermal metasomatism within the alteration pipe produced a concentric zonation. with a peripheral quartz - sericite - chlorite mineral assemblage surrounding an axial core of magnesian chlorite - Phlogopite.

Jan 1, 1989

Rock bolting provides a supplement or alternative to conventional timber and steel supports. The tensile strength of the bolts lies within a range established by manufacturing quality control. Rock bolt testing determines the ability of the rock, anchor and individual bolt as an assembly to accept load. The.test is performed to the yield strength of the bolt or anchor and deflection is observed. The anchorage index, inches deflection per 1000 lb load increment, is a measure of anchorage quality. This allows comparison with anchorages under ideal conditions. It also permits comparative assessment of roof bolt anchors in a particular environment.

Jan 1, 1971