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The most meaningful way to estimate the current value and the future value of a mining company is to consider the cash flow of the company through time. This is the case since the reported earnings of a mining company are highly sensitive to the accounting practices followed and to changes in metal prices. The valuation of a mining company is strongly dependent on the forecasting of the expected net cash flows of the company. The computer model presented herein has been designed to assemble all of the pertinent variables relating to a mining operation and to calculate the net cash flow for a mining company. The diversity of the operations in the mining industry has necessitated the development of a general model which can be applied to a number of different situations. The model has been developed for base metal mining operations which, produce any combination of the following seven metals: copper, lead, zinc, gold, silver, cadmium and molybdenum. The model has been divided into thirteen subroutines and a main programme. Each of the subroutines corresponds to a particular phase of the mining operation. In this way, the critical variables in the operation can be isolated and examined in detail. Although the model is complex and requires a large amount of data, it is hoped that its use will be straightforward and that it will be of assistance to those persons interested in the valuation of a mining company. / Business, Sauder School of / Operations and Logistics (OPLOG), Division of / Graduate

The principal functions of underground mine pillars are to stabilize openings and to carry the load of overlying rock strata. They are often (partially or completely) recovered at a later stage when their stabilizing effect is no longer required. For economic reasons, an optimum-sized pillar is the smallest one satisfying safety requirements. Thus the pillar design problem consists of determining the pillar's minimum dimensions as the load approaches the ultimate pillar strength. Because the pillar's strength and the load acting upon it are both functions of many interrelated factors, which may vary as mining progresses, the determination of pillar dimensions is a complex task. Furthermore, the multiplicity of pillar shapes, sizes, rock material and functions add to the designers' problem. Consequently, pillar design programs are still generally performed as a trial-and-error process. In order, to improve the present pillar design practices (1) -AApillar classification is proposed to standardize the design procedure (2) The principal design methods, divided into four groups, are summarized and their applicability is is defined (3) A five-phase design procedure with design charts is developed (4) The design procedure is applied in analysing two case histories / Applied Science, Faculty of / Mining Engineering, Keevil Institute of / Graduate

The design of open stope rib pillars has been done using many empirical methods, but none of the methods has been verified with a design survey. This thesis uses data collected in the "Integrated Mine Design Study" to develop an empirical rib pillar design method for open, stope mining. The method is called the "pillar stability graph". The design variables in the method are: the compressive strength of the intact pillar material, the average pillar load determined by numerical modelling, the pillar width and the pillar height. The graph has been refined with the use of more than 80 literature case histories of hard rock pillars in room and pillar mining. The pillar stability graph and the pillar data base are used to examine the applicability of empirical methods commonly used in open stope rib pillar design. The investigation found the pillar strength curves developed by Hoek and Brown (1980) may be useful under some conditions for the design of open stope rib pillars but formulas by Hedley (1972), Obert and Duvall (1967) and Bieniawski (1983) are not applicable. Guidelines, using the pillar stability graph method, are proposed for the design of permanent open stope rib pillars, stable temporary open stope rib pillars, and failing temporary open stope rib pillars. / Applied Science, Faculty of / Mining Engineering, Keevil Institute of / Graduate

Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Mining and Metallurgy, 1967. / Vita. / Includes bibliographical references (leaves 95-106). / by Amitava Gangulee. / Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Mining and Metallurgy, 1967.

A presente tese apresenta uma contribuição técnico-econômica à atual mineração brasileira de fluorita, que foi profundamente modificada pelo desenvolvimento de novos e importantes depósitos. Tendo-se em vista a importância econômica do mineral, no atual contexto industrial, são analisados os usos e aplicações da fluorita, as principais propriedades físico-químicas do elemento flúor e de seus minerais, bem como as características estruturais e genéticas dos depósitos minerais que condicionam o aproveitamento industrial. Essa abordagem tem por objetivo não somente rememorar os conhecimentos técnicos, como também investigar as conexões que devem existir entre as várias fases de desenvolvimento pelas quais um empreendimento mineiro passa até a sua consolidação. Diversos fatores técnicos pertinentes à indústria mineral são discutidos, com ênfase às características peculiares da mineração de fluorita, incluindo a recente usina de beneficiamento inaugurada no Alto Vale do Ribeira, no Estado do Paraná. Os aspectos relativos à produção, custos e mercados são examinados no âmbito do comércio nacional e internacional. Finalmente, a demanda futura da fluorita na indústria nacional é estimada com base no crescimento acelerado da produção brasileira de aço bruto e alumínio primário. / This thesis is a contribution to the present technical and economical aspects of the brazilian fluorite mining industry, which hás been deeply affected by recent development of several importants deposits. Due to the economic importance of fluorite for the brazilian industry, its main applications are analysed, along with consideration on the physico - chemical properties of fluorine and associated important mineral. Genetic and structural characteristics of the mineral deposits affecting the industrial recovery of fluorite are also discussed. Throughout the whole report there is a search for the linking elements that must exist between the several phases of a complete mining Project, from the initial stages up to the operation point. A brief review of the existing operating and their technical characteristics is presented, i8ncluding some details of a fluorite Project recently started at the Upper Vale do Ribeira, in the Paraná State. Production, cost and market aspects are examined from national and international viewpoints, and finally future consumption trends are evaluated, considering the rapi evolution of the raw steel and primary aluminum productions.