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Unconventional PGE occurrences and PGE mineralization in the Great Dyke: metallogenic and economic aspects 总被引:4,自引:0,他引:4
B. Stribrny F. -W. Wellmer K. -P. Burgath T. Oberthür M. Tarkian T. Pfeiffer 《Mineralium Deposita》2000,35(2-3):260-280
Platinum group elements (PGE) are strategic materials because 96–99% of the world production is derived from just five mining
districts and because they cannot be replaced as catalysts in many chemical processes. In order to lessen the strategic character
of PGE, both conventional deposits and unconventional PGE mineralizations were investigated in an attempt to locate viable
deposits which would diversify the supplier base. In the Great Dyke, conventional PGE mineralization occurs in the form of
pristine sulfide ores mined underground and oxidic surface ores. New observations such as bimodal distributions of the PGE
in the Main Sulfide Zone (MSZ), elevated Pt/Pd ratios in the oxidized MSZ compared to the sulfidic part and distinct differences
between the platinum group mineral (PGM) assemblages of the MSZ and stream sediments of adjacent rivers emphasize the fact
that even though the Great Dyke seems to be the second or third largest PGE occurrence in the world, the complicated PGE distributions
and supergene redistributions should be kept in mind during planning and mine operation. Investigations of unconventional
PGE occurrences in ophiolites, Alaskan-type intrusions, porphyry copper deposits and in the Kupferschiefer show that economically
exploitable PGE concentrations can be expected in a broader variety of host rocks than considered favourable in the past.
In the Albanian Mirdita ophiolite average contents of 860 ppb Pt and 60 ppb Pd were detected. Flotation concentrates of porphyry
copper deposits, for example from Mamut, Malaysia, Santo Tomas, Philippines, Elacite, Bulgaria, and Ok Tedi, Papua New Guinea,
contain between 827 and 1860 ppb Pd + Pt. In selected profiles of the Polish Kupferschiefer average contents of 255 ppb Pt,
94 ppb Pd, 2.4 ppm Au and 13.0 ppm Ag were analysed. The distribution of the PGE resources in the world and the annual production
rates, however, underline the fact that the chances for a significant change in the supplier base are relatively low. The
Bushveld Complex will remain the largest producer, followed by Noril'sk-Talnakh, Sudbury and Stillwater. If the operations
in the Great Dyke reach their planned capacities, the Great Dyke will rank in third place among the PGE-producing deposits
in the world.
Received: 12 September 1998 / Accepted: 7 December 1999 相似文献