Study On The Character And The Resources Evaluation Of The Littoral Placer In2816L, Mozambique

With Chinese economy developing continuously and quickly, the contradiction of mineral resources shortage is becoming more and more outstanding. Therefore, while using domestic mineral resources reasonably, utilizing foreign mineral resources furthest has also become a strategic activity. The purpose of the strategic activity is to build up a mineral resource supply system of diversity, stability, safety for China, and to guarantee the sustainable development of the Chinese economy.Because mineral resources of the land are reducing gradually, the target of exploration is directed to the sea. The littoral placer is one of the latent resources that can increase mineral resources reserve. All the more, minerals in the littoral placer are extensively applied; investment of littoral placer exploitation is little; exploitation of littoral placer is convenience.Mozambique is located in the southeast of Africa and close to Indian Ocean. It has a coast line of the2500kilometers in length. Its inner mainland part is mainly covered by metamorphic rock and igneous rock of Precambrian, which contains abundant heavy minerals:ilmenite, zircon, rutile, urdite, leucoxene, cyanite, andalusite and so on. Under the rain effect, heavy minerals deposited along the coast line and formed littoral sand bed through weathering, denudation and transportation. The detailed exploration of the prospective area in the2816L mine area in Mozambique not only can provide foreign reserves of heavy mineral resources for the country but also can accumulate materials for compiling coastal placer mineral prospecting specifications. Through the research of the heavy mineral degree of comprehensive utilization of mine resources, the utilization value can be improved. Therefore, launching geological survey and comprehensive utilization of heavy minerals in2816L placer deposit have real and long-term social and economic benefits. The main achievements are as follows.(1) Discussions on the layout of the engineering span of exploration lines in mining areas and practice have proved that the decision is effective which can effectively locate the ore body boundaries and reduce the exploration cost. Through detailed exploration, the grade and the thickness of the ore bodies on5exploration lines have been analyzed, and the exploration type of the2816mine area is decided as type I.Compared with the engineer span of400m×40m, it is more reasonable to control resources reserve of heavy sand minerals with the800m×40m engineer span; four washing times for not-precious-metal detailed exploration can satisfy the production request; in order to satisfy both construction progress and resources classification, shallow bore (8-10meters deep) and deep bore (20meters deep) is combined in practice. The exploration methods mentioned above lay foundation for establishing geology exploration method of littoral placer.(2) With the Optical microscope, the X-ray diffractometer, the Scanning Electron Microscope, the ICP-MS devices and the mathematical statistics method, the mineral composition and characters of the placer in2816L mine area is analyzed. By using mathematical and statistical method, element occurrence state and the carrier minerals in the heavy mineral are discussed. The result shows that①ilmenite, rutile and zircon are the main minerals of the placer, and the main gangue minerals are quartz and feldspar.②Zr and Ti are the main Chemical Components of the heavy minerals, Hf and REE(Rare Earth Element) are minor, and Th and U are harmful components.③some correlations are shown between the content of chemical components and the grain size of heavy minerals:the grain size of the carrier mineral of Zr, Hf, U, Cr, Ta, such as zircon, urdite, xenotime are comparatively fine grained, and the grain size of the carrier mineral of Ti, Fe, V, Nb, such as ilmentite, rutile and magnetite are comparatively coarse grained. (3) The result of the estimation of the resources reserve shows that:ilmenite176.55×104t, rutile5.79×104t, zircon16.85×104t is acquired in the2816L mine area. The beneficiation test results show:the industrial minerals are ilmenite and zircon; ilmenite recovery is more than eighty-seven percent and titanium recovery is more than seventy-five percent; zircon recovery is more than eighty-two percent and zirconium recovery is more than seventy-four percent; The mineral stone (sand)’s quality is good. The resources are of great capacity. Technique conditions of mining are simple. The economic efficiency of mining is good.Through detailed exploration and research in2816L mine area, the mineral composition and characters of littoral placer are acquainted; it reveals that the mineral resources in the area are of great comprehensive utilization value. Through the research of resources evaluation, it is confirmed that the quality of the mineral resources are good, the quantity is huge and of good economic efficiency in mining, for example, the reserves of ilmenite, rutile and zircon can fulfil a ten-year mining plan with a simple technique conditions requirement of mining.Besides, the method adopted in the detailed exploration laid a foundation for establishing geological exploration method of littoral placer.