Abstract
When planning highly selective mining operations, the challenge is to estimate mineable ore reserves that will be selected at the mining stage. From exploration data it is not possible to estimate accurately the grade (or thickness) of each future selective mining unit; however, it is possible to estimate the local distributions of these mining unit grades within large panels suitable for long-range mine planning. Application of a cut-off then allows estimation of the recovered ore tonnage and grade within each such panel. Derivation of local conditional distributions is rather simple when the grade is either normally or lognormally distributed. The geologically important lognormal case is fully described both in the stationary and the nonstationary case. Cross validations of these techniques using the exploration data of the Imouraren uranium deposit are presented.
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References
Aitchison, J. and Brown, J., 1957, The lognormal distribution: Cambridge University Press, London.
Delfiner, P., 1975, Linear estimation of non-stationary spatial phenomenain Proceedings of the “Geostat '75” NATO ASI Congress (Reidel Publ. Corp., ed.): Dordrecht, The Netherlands, p. 49–68.
Jackson, M. and Marechal, A., 1979, Recoverable reserves estimated by disjunctive kriging: A case-studyin Proceedings of the 16th APCOM Symposium: Tuscon, Arizona, October 1979.
Journel, A. G., 1977, Kriging in terms of projections: Math. Geol., v. 69, no. 6, p. 563–586.
Journel, A. G. and Huijbregts, C., 1978, Mining geostatistics: Academic Press, London, 600 p.
Marechal, A., 1974, Krigeage normal et lognormal: Centre de Morphologie Mathematique, Fontainebleau, France (Unpublished note N-376).
Matheron, G., 1974, Les fonctions de transfert des petits panneaux: Centre de Morphologie Mathematique, Fontainebleau, France (Unpublished note N-395).
Matheron, G., 1975a, A simple substitute for conditional expectation: Disjunctive krigingin Proceedings of the “Geostat '75” NATO ASI Congress (Reidel Publ. Corp., ed.): Dordrecht, The Netherlands, p. 221–236.
Matheron, G., 1975b, Forecasting block grade distributions: The transfer functions,in Proceedings of the “Geostat '75” NATO ASI Congress (Reidel Publ. Corp. ed.): Dordrecht, The Netherlands, p. 237–251.
Parker, H. M., Journel, A. G., and Dixon, W. C., 1979, The use of conditional lognormal probability distribution for the estimation of open-pit ore reserves in stratabound uranium deposits: A case-studyin Proceedings of the 16th APCOM Symposium: Tucson, Arizona.
Parker, H. M. and Switzer, P., 1975, Use of conditional probability distributions in ore reserve estimation: A case-studyin Proceedings of the 13th APCOM Symposium: Clausthal, West Germany, p. M II, 1–16.
Rendu, J. M., 1979, Normal and lognormal estimation, Jour. IAMG, v. 11. no. 4, p. 407–422.
Wilks, S. S., 1962, Mathematical statistics: Wiley, New York.
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Journel, A.G. The lognormal approach to predicting local distributions of selective mining unit grades. Mathematical Geology 12, 285–303 (1980). https://doi.org/10.1007/BF01029417
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DOI: https://doi.org/10.1007/BF01029417