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As part of a joint research project on fine particle processing by COREM, Natural Resources Canada and Hydro-Quebec, two flotation plant circuits were sampled to identify and quantify the causes of mineral losses within several particle size ranges. Size distributions, size-by-size assays and global chemical assays (Cu, Zn, Fe, S) were performed for the major streams. Size distributions were measured in 13 classes by sieving, cyclosizing (minus 45 microns) and laser diffraction analysis. BILMAT, a material balance computation package, was used to optimise the sampling, to estimate the unmeasured variables, and to assess and improve the quality of the information generated. The BILMAT methodology has been extended to correct cyclosizer data and to reduce discontinuities of up to 20% at the transition from sieves to cyclosizer. Results show that the correction of cyclosizer data has a significant effect on the flowsheet materials balance. The critical size below which the recovery drops was evaluated at 10 microns for the three sulphide flotation circuits., As part of a joint research project on fine particle processing by COREM, Natural Resources Canada and Hydro-Quebec, two flotation plant circuits were sampled to identify and quantify the causes of mineral losses within several particle size ranges. Size distributions, size-by-size assays and global chemical assays (Cu, Zn, Fe, S) were performed for the major streams. Size distributions were measured in 13 classes by sieving, cyclosizing (minus 45 microns) and laser diffraction analysis. BILMAT, a material balance computation package, was used to optimise the sampling, to estimate the unmeasured variables, and to assess and improve the quality of the information generated. The BILMAT methodology has been extended to correct cyclosizer data and to reduce discontinuities of up to 20% at the transition from sieves to cyclosizer. Results show that the correction of cyclosizer data has a significant effect on the flowsheet materials balance. The critical size below which the recovery drops was evaluated at 10 microns for the three sulphide flotation circuits.

Study results show that Ontario has a strong competitive position in the shield region and in Canada. A marked deterioration is found in the potential value of base metal exploration in Ontario and throughout Canada during the past 20 years, culminating in uneconomic results for 1976-85, the most recent decade analysed. The economic potential of gold exploration, on the other hand, appears to be improving with time. Ontario's taxation policies are shown to have a substantial negative impact on investment incentive. However the three-year tax exempt period for Ontario mining tax, introduced in 1987, is shown to have a significant positive effect on the after-tax incentive for exploration and development. The potential values assessed in the study provide a portrait of the mineral supply process that can be applied when looking ahead to describe the distinctive economic characteristics of mineral exploration and mine development in Ontario for government policy analysis. More generally, the study illustrates the type of data base, evaluation procedure, and economic assessments that can be developed and used on an on-going basis., Study results show that Ontario has a strong competitive position in the shield region and in Canada. A marked deterioration is found in the potential value of base metal exploration in Ontario and throughout Canada during the past 20 years, culminating in uneconomic results for 1976-85, the most recent decade analysed. The economic potential of gold exploration, on the other hand, appears to be improving with time. Ontario's taxation policies are shown to have a substantial negative impact on investment incentive. However the three-year tax exempt period for Ontario mining tax, introduced in 1987, is shown to have a significant positive effect on the after-tax incentive for exploration and development. The potential values assessed in the study provide a portrait of the mineral supply process that can be applied when looking ahead to describe the distinctive economic characteristics of mineral exploration and mine development in Ontario for government policy analysis. More generally, the study illustrates the type of data base, evaluation procedure, and economic assessments that can be developed and used on an on-going basis.

The positive expected values assessed for the base metal and gold potential in Newfoundland are found to be significantly lower than those which more broadly characterise the Appalachian region and Canada. The potential value of base metal exploration in the region is shown to have made an encouraging comeback in the most recent decade analysed (1976-85). Newfoundland's taxation policies are shown to have a substantial negative impact on investment incentive. The effects of Newfoundland's taxation system tend to be on the onerous side of the spectrum of Canadian inter-provincial assessments presented. The comparative impact of five types of regional development policy: geologic data base development, direct exploration assistance, support for new mine development, mine production incentives, and end-of-mine assistance are illustrated. While the assessments are of an exploratory nature, they suggest that geologic data base development would have the greatest impact on enhancing economic performance. The potential values assessed in the study provide a portrait of the mineral supply process that can be applied when looking ahead to describe the distinctive economic characteristics of mineral exploration and mine development in Newfoundland for government policy analysis. More generally, the study illustrates the type of data base, evaluation procedure, and economic assessments that can be built up and used on an on-going basis., The positive expected values assessed for the base metal and gold potential in Newfoundland are found to be significantly lower than those which more broadly characterise the Appalachian region and Canada. The potential value of base metal exploration in the region is shown to have made an encouraging comeback in the most recent decade analysed (1976-85). Newfoundland's taxation policies are shown to have a substantial negative impact on investment incentive. The effects of Newfoundland's taxation system tend to be on the onerous side of the spectrum of Canadian inter-provincial assessments presented. The comparative impact of five types of regional development policy: geologic data base development, direct exploration assistance, support for new mine development, mine production incentives, and end-of-mine assistance are illustrated. While the assessments are of an exploratory nature, they suggest that geologic data base development would have the greatest impact on enhancing economic performance. The potential values assessed in the study provide a portrait of the mineral supply process that can be applied when looking ahead to describe the distinctive economic characteristics of mineral exploration and mine development in Newfoundland for government policy analysis. More generally, the study illustrates the type of data base, evaluation procedure, and economic assessments that can be built up and used on an on-going basis.

A flexible crushing plant simulator - CRSHEX - has been developed at CANMET. The advantage of designing a plant with the CRSHEX simulator is obtaining first results rapidly. The first sample-run simulation was completed within an hour. Modifications took only a few minutes. Results were accurate enough to decide the initial setting range for most of the equipment. In minutes, a realistic quarry flowsheet can be tested to achieve preset production levels and quality., A flexible crushing plant simulator - CRSHEX - has been developed at CANMET. The advantage of designing a plant with the CRSHEX simulator is obtaining first results rapidly. The first sample-run simulation was completed within an hour. Modifications took only a few minutes. Results were accurate enough to decide the initial setting range for most of the equipment. In minutes, a realistic quarry flowsheet can be tested to achieve preset production levels and quality.