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Organic dyes such as nigrosine and sun yellow act as depressants for carbonaceous particles in the, flotation of sulphide ores. Depression is achieved when initially hydrophobic organic surfaces are made hydrophilic by preferential adsorption of dye molecules. Experimental studies, mainly on Mount Isa ores, indicate that dyes are adsorbed as planar anionic micelles attached to carbonaceous surfaces by van der Waals and ion exchange attractive interactions. Relationships appear to exist between the amount of organic matter on the surface of ground particles, the surface area of the particles, the "saturation" adsorptions of dyes, and the degree of difficulty experienced during froth flotation.

Jan 1, 1975

Asarco's newest concentrator near Troy, Montana, began operation in October 1981, and is presently milling ore at its design capacity of 7,710 metric tonnes per day. The underground room-and-pillar mine produces a readily floatable copper sulfide- native silver ore in a quartzite gangue. Major sulfide minerals are bornite and chalcocite with minor chalcopyrite; fine grained native silver occurs with the copper sulfides. There are also minor amounts of native copper and copper oxides in the ore. A rougher copper-silver concentrate is floated, reground and cleaned twice. Cleaner tail is scavenged, and the scavenger concen- trate is combined with rougher concentrate for regrinding. Rougher flotation tailing and scavenger tailing make up final mill tailing which is disposed of by spigotting into a tailing dam located 10.5 km from the mill site.

Jan 1, 1978

Economic evaluations of mineral projects are based on discounted cash flow analyses, followed by sensitivity and risk analyses. However, the global macroeconomic and political environment in which the mineral industries operate have a profound effect on the viability of individual projects. Since the oil crises of 1974 and 1980, demand patterns for minerals have become much more variable and prices more volatile. Significant changes in the geographical distribution of world mineral supply and demand are underway, and the mix of minerals used is also changing. Social and political factors are as important as economic and technical factors in determining the viability of mineral ventures. Economic evaluation of mineral projects have to be undertaken in a more uncertain and risky environment. They can no longer be reduced to a number crunching exercise.

Jan 1, 1987

By K Steamy, D Lesmana, K Yulia

Effective selective mining relies heavily on high quality geological data and assay data. Such assay data is dependent on effective sampling protocols, sample preparation techniques, assaying practices and well founded quality assurance/quality control (QA/QC) procedures. This paper describes recent developments in grade control sampling at PT Nusa Halmahera Minerals high-grade Kencana gold mine at Gosowong Indonesia and presents a case study in identifying, minimising and monitoring random and systematic sampling error including the use of duplicate sampling and the Thompson Howarth technique for quantifying random sampling error.

Jan 1, 2009

By Owen D

A central part of mine planning is to ensure the protection of the beneficial uses of water. Integrated mining software does not generally provide tools to help the mining engineer to achieve this objective. This paper identifies some of the requirements which are desirable for such a tool and discusses how object oriented modelling can help achieve an effective design.

Jan 1, 1995

The effect of temperature, time and SO2 concentration in the atmosphate have been studied for a complex Pb-Zn concentrate, which contained four sulphides and some organic material, in order to determine optimum roasting conditions. Under static roasting conditions virtually complete sulphation was achieved after roasting at 650¦C.2 hours in 10% SO2 in air. Both zinc ferrite and zinc silicate were observed to form early in the roasting, but continued exposure to SO2 -containing gases caused decomposition of these as the roasting time increased. Water and acid solubilities of iron, silica, calcium, magnesium and aluminium in the calcine were determined, as a function of roasting time, temperature and atmosphere composition.

Jan 1, 1970

By Morgans DJ

The aim of this paper is to highlight the social aspects involved in the preparation of environmental impact studies (E.I.S.'s) for mining developments. In particular, the paper will reveal that the social information provided in such E.I.S.'s can achieve much more than simply satisfying government requirements. Such information can form the basis of a strategy to deal with the settlement of a mine workforce in either an existing or newly developed community. A strategy of this type can go a long way towards avoiding many of the social problems and related industrial disputes often created in such circumstances. It will also be of significant benefit to the mining company in negotiating its infrastructure package with the local authority.

Jan 1, 1987

The word `environment' may have many different meanings but, for the purposes of this paper, I have assumed the definition included in the Environmental Protection Act 1986 (Western Australia). This Act defines `environment' as `... living things, their physical, biological and social surroundings, and interactions between all of these'. The Act further defines the `social surroundings of man' as `... his aesthetic, cultural, economic and social surroundings to the extent that those surroundings directly affect or are affected by his physical or biological surroundings'. This gives a very broad meaning to the idea of environment and environmental issues, and it is therefore understandable that the influence that environmental issues have on mining activity can vary so much from state to state, and even within states, and why the degree of influence can change so much with time.

Jan 1, 1990

By Slattery T. E

Recent develognents in zinc flotation at the North Broken Hill Limited concentrator are discussed. An outline of the history of zinc flotation and a description of current practice is presented. Installation of on-stream X-ray analysis probes has resulted in inproved metallurgical performance and focussed attention on automatic control. Results are presented of investigations made over the past six years which have led to the formulation of experimental schemes for the automatic control of zinc flotation.

Jan 1, 1983

By Linge H. G

The effect of the presence of ore pulp on the adsorption rate of gold on activated carbon has been studied. A substantial reduction in the rate occurs when the pulp is present. The reduction in rate appears to be caused by two effects: permanent carbon pore blocking by ore particles and temporary shielding of the carbon particle surface, slowing gold access to the carbon due to the physical presence of the fine pulp. There is no significant effect arising from the presence of a pulp viscosity modifier even for conditions when mass transport dictates the loading rate of carbon in clear Solution.

Jan 1, 1987

The Merrill-Crowe process for gold and silver recovery yields a low grade concentrate containing high levels of zinc and copper. External refining charges and high transport costs prompted the company to establish itsown enrichment facility.The route chosen was a wet chemicaltreatment which converts the gold, silver and other metals to their chloride. This is achieved with hydrochloric acid and sodium hypochlorite. Gold is recovered from the resulting filtrate by cementation with copper.The solid residue from the gold process is washed and treated with ammonia which dissolves the silver chloride. Metallic silver is recovered from this solution, againby cementation with copper.

Jan 1, 1985

In recent decades the awareness of environmental issues by the general public has developed at an accelerat- ing rate. This is the result of a number of factors including more scientific knowledge of environments and of the impacts of modern society upon them, higher levels of education, the opportunity for people to travel more, and the success of the various communication media in bringing in- formation to the communities of the world about such environmental crises or threats as the smogs of Los Angeles and London, the Torrey Canyon and Santa Barbara oilspills, Minamata disease in Japan, the spread of the Crown of Thorns starfish, the disposal of toxic industrial wastes into the Upper Rhine, the discovery of high mercury and zinc contents in marine foods in southern Australian waters, and the proposal to mine limestone at Precipitous Bluff in Tasmania.

Jan 1, 1975

By A E. McElnea, M A. Martens

An 18-month project was undertaken to test the effectiveness of controlled daily tidal exchange augmented with hydrated lime treatment of surface waters as an approach for remediating a severe acid sulfate soil disturbance at East Trinity, Cairns, north Queensland. Actual acid sulfate soils were producing hazardous levels of acid and heavy metal contaminants and degrading approximately 720 of the 940 ha East Trinity property and the adjacent foreshores. A government-led research team established a series of research projects with the aim of characterising the site (soils, water, terrain) and testing the effect of the lime-assisted tidal exchange management strategy on soils, water, sediments and biota.

Jan 1, 2003

By Barrett D

The paper discusses the justification for the Open Pit Mining Operation at Central Norseman Gold Corporation Limited's North Royal facility.Open pit mining history is outlined together with production statistics and associated costs. Underground mining practice is discussed together with an outline of the problems with mining in oxidised ground.

Jan 1, 1984

By T Galvin

Drilling and blasting at Westside Mine near Wallsend, NSW, has presented a challenge for Orica Explosives, Australia. The colliery produces 600 000 tonnes of steaming coal per year from two seams using surface mining techniques. Tapping into underlying coal will greatly improve the yield, but there are many issues which make this an enormous challenge. Hunter Valley Earthmoving engaged Orica Explosives to supply the explosives products and to provide much of the blasting expertise that is needed on the minesite. Hunter Valley Earthmoving and Orica Explosives have proven to be an outstanding, unified technical team on this project. The success of the team is based on good communication, progressive attitudes, extensive expertise in blast design and most importantly, care and accuracy in implementing the agreed upon designs.

Jan 1, 1999

By P McCarthy

Despite significant advances in the platform technologies that could form part of a system of mine automation, the goal of full automation in most underground mining applications remains distant. This is because the industry developed these platform technologies to achieve local improvements in safety, machine and labour productivity, and asset utilisation, rather than to work towards a goal of a complete system of automation for general application in underground mines. This paper reviews the history and current state of automation in the underground mining industry and uses lessons learnt from the automobile and general manufacturing industries to gain insight into the opportunities and pitfalls in the complex and uncertain path to automation of underground mines. It also evaluates the relevance of the current drivers of interest in the industry. From this, we hope to engender an attainable vision of automation in underground mining and determine the best development path, process and timeline to achieve this vision.

Jan 1, 2008

By Hughes A

Nchanga Division of ZCCM has installed and operated a trolley assist system on part of their truck fleet for some three years. This paper examines how the system came to be chosen and how the many features of construction and operation were dealt with. The economics and productivity of the system are presented as are the personnel aspects of acceptance and training. Zambia Consolidated Copper Mines is a state controlled copper mining company formed by the amalgamation of the former Nchanga Consolidated Copper Mines and Roan Copper Mines. The company operates seven copper mines the largest producer being the Nchanga division, which is scheduled to produce some forty-two percent of Zambia's copper production. The division operates four open pits and an underground mine which produce annually some 192 000 and 96 000 tonnes respectively of copper contained in ore.

Jan 1, 1986

A modular computer-based monitoring system for mines is dis-cussed. The system consists of the following modules : production moni-toring system HADES, methane monitoring system CMC, seismoacoustic and seismometric systems SAK and SYLOK, communication systems. The system enables one to compose flexible,` economic structures according to the specification of a mine. Application of microcomputer-based monitoring and control systems in coal preparation plants also is discussed.

Jan 1, 1985

By Weber D, Knox PR

The criteria developed for the Argyle Diamond Mine process plant control system are reviewed. The control system installed is described along with a discussion of the method of implementation adopted. The control system was extensively tested prior to instal- lation at site. This approach led to signi- ficant time savings during plant commissioning and facilitated rapid escalation of plant production. The control system has performed satisfactorily with a high level of operator acceptance and basically satisfies the criteria Developed.

Jan 1, 1986

The development of the SECV brown coal open cut at Loy Yang will require depressurisation of aquifers both within and below the coal seam sequence in order to maintain open cut stability. Prediction of future open cut dewatering requirements at Loy Yang Open Cut and evaluation of the regional consequences of dewatering has required development of a detailed hydrogeological model of the Loy Yang area. The complex stratigraphy of the coal seam and aquifer/aquitard sequences at Loy Yang have been analysed and integrated with the hydrogeological concepts developed from regional groundwater studies to formulate a realistic hydrogeological model as a basis for finite-element flow modelling.

Jan 1, 1988