The Japan International Cooperation Agency (JICA) and the Metal Mining Agency of Japan (MMAJ) have been conducting since 1995 a mineral exploration project in the Batinah Coast area, Sultanate of Oman. During this project, three concealed ore bodies were discovered in Ghuzayn, with a total ore reserve of 14 million tons averaging 1.6 % copper.
Based on the survey results obtained during the project, following exploration indicators has been established: (a) massive sulphide deposits show stratigraphic control, (b) the alteration associated with mineralization consists of silicification, chloritization(Mg-rich chlorite) and epidotization, (c) the generation of massive sulphide deposits is closely related to faults, and (d) massive sulphide ore grades laterally into metalliferous sediments.
Since this area is widely covered by Quaternary sediments, the features of mineralization can be rarely seen on the surface and for this reason, the exploration work can be more effective if the following steps are taken into account: (1) select potential areas by geological and airborne geophysical surveys to extract mineralized features along the horizon which may bear massive sulphide ore bodies, (2) delineate the zones of high potentiality in more detail by appropriate ground geophysical methods such as IP method to clarify the mineralized zones and subsequently, TEM method to extract possible ore bodies from the mineralized zones, and (3) carry out a suitable exploratory drilling program to confirm the results.

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The Japan International Cooperation Agency (JICA) and the Metal Mining Agency of Japan (MMAJ) have been conducting a copper resource assessment in the Batina Coast Area, Sultanate of Oman as a part of Technical Cooperation for Mineral Resources program. Up to 1997, the survey identified three concealed ore bodies in the Ghuzayn area, with a total ore reserve of 14 million tons averaging 1.6% copper.
Preliminary study indicates that the ore deposits are currently difficult to develop given their depth, size, grade, and the recent copper price decline. However, a sensitivity analysis indicates the discovery of, new deposit at a depth less than 100m, or with ore grande above 0.5g/t gold, or an increase in the present reserve of 60% would prove the area profitable.
Taking these estimations into account, the survey during the remaining 1998 to 1999 term will focus on discovering new deposits in the unexplored and potentially prospective zone in the vicinity of existing ore bodies.

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Stream sediment geochemistry has shown to be a effective method for identifying areas of mineral potential. In 1997, the MMAJ conducted a stream sediment sampling program in the Esashi area of northern Hokkaido. Minus 200 mesh samples were collected at a density of approximately 0.7sample/km2 and analyzed for Au, Hg, As and other 30 elements. Gold anomalies are apparent in the Motokura mine area and other areas where the Hidaka group rocks crop out. Arsenic anomalies also occur in the Motokura mine area. A mercury anomaly was also identified in the Honhorobetsu area. These results indicate that stream sediment chemical anomalies correlate well with old mining districts and zones of known mineralization. It was also shown that the minus 200 mesh fraction can minimize the nugget effect and therefore be used as an effective mineral exploration tool.

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In this paper, I introduce an example of an airborne electromagnetic survey for a uranium exploration project, focusing on the newly adopted data-processing method.
In 1996, we performed an airborne electromagnetic survey for a uranium exploration project in Arnhem Land, Australia. The aim of the survey was to map conductive zones, which might be related to uranium mineralization. A major concern in airborne electromagnetic surveys in this area is the existence of a conductive near-surface layer, which is considered to mask deeper resistivity features. After performing some simulations, we confirmed that our target conductive zones could be identified by using a multifrequency airborne electromagnetic survey despite the existence of the relatively conductive surface in this area.
In the data processing of the survey, we tried multi-element image-processing techniques, such as RGB compositi and image ratio operations, to cope with surface conductivity variations. That those processing results mapped basement conductive zones was supported by vertical electric sounding and confirmed by drilling.
The application of these image-processing techniques to the survey data was also intended as a test of the suitability of these techniques for further multi-element intergrated analysis: combined analysis using several survey methods. The phrase "multi-element integrated analysis" refers here to the production of geological indicators from several types of (geophysical) data, which usually have different spatial density, accuracy and resolution, by analyzing them together statistically. Since a direct correspondence between geological features and observed geophysical survey data is rare, our final goal was to establish multi-element integrated anlysis as a tool for linking them. The trial described in this paper is the efirst step toward this goal.

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Sumitomo Metal Mining Arizona, Inc. and three other international companies formed the Stone Boy joint venture in 1991 and started a regional grassroots exploration program east of Fairbanks (Stone Boy area) focusing on SEDEX type lead-zinc and gold deposits.
The region is underlain by highly deformed, amphibolite-grade gneiss of the late Proterozoic to mid-Paleozoic Yukon-Tanana terrane, intruded by Cretaceous granitoid bodies. In 1994, the first diamond drill hole on the Pogo claims intersected the high grade gold mineralization (15ft, 27g/t Au) which was later confirmed to be a part of the Liese gold deposit. The Liese Au de-posit has an estimated gold resource of 162 metric tonnes with an average grade of 17.8 g/t Au as of December 1998. Exploration to date on the Pogo claims has focused on the Liese Zone in the northwest part of the claims. Mineralization in the Liese Zone consists of at least two large, tabular gold-quartz bodies, designated L1 (Liese main ore body) and L2 (Liese lower ore body). These quartz bodies contain approximately 3% sulphides, including arsenopyrite, pyrite, pyrrhotite and loellingite. Other minor metallic minerals include various Au, Bi, Te, Cu, Pb, Zn, Ag, W and Mo minerals. Au-Bi has the most significant positive correlation.
In addition to the Liese gold-quartz mineralization, two other styles of gold mineralization, stockwork and gold sulphide dissemination were discovered in the Pogo area. The Liese gold-quartz mineralization has some similar earmarks to the mesothermal gold quartz veins in the Fairbanks mining district, however its formation temperatures (300°C to 600°C) and trapping pressures (1, 700 to 2, 000 bar) are higher than those veins, and microscopic studies have revealed that the Liese gold-quartz is not vein but meta-quartzite due to its equigranular granoblastic texture. Arsenopyrite geothermometry indicates temperatures of 380°C to 600°C for the Liese deposit and 520°C for the North Zone stockwork gold mineralization. Fluid inclusion studies have suggested that the Liese deposit has homogenization temperatures of 290°C to 580°C, and was formed under ductile conditions at about 6km below the paleosurface. Stable isotope analysis of the Liese deposit indicates that the δ³⁴S values of sulfide minerals are±0 (-1.4 to +2.8%) suggesting mantle origin, δ¹⁸O values of gold-quartz are +12.3 to +15.7‰ and estimated δ18O values of hy-drothermal fluid are +5.07 to +10.40‰, which are similar to those of magmatic or metamorphic water. Evidence suggests that the Liese deposit is a metasomatized quartz or a tectonized quartz vein, or a combination of both formed within tectonic shear zones under high P/T conditions.
The radiometric dating of the alteration minerals at Pogo suggests that the Pogo gold mineralization took place between 97.7Ma, and 91.2Ma, and well coincides with the ages of granodiorite (96.6Ma to 91.9Ma) and diorite (97.9Ma to 91.1Ma).
The genesis of the Liese deposit still remains enigmatic and controvertial. Underground exploration, envirofimental studies, and final feasibility, including all engineering work and plant scale metallurgy will be completed by the end of the year 2000 with the intention of bringing the Liese deposit into production.

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The Christie Lake project area is located in the eastern part of the Athabasca Basin, Canada. The exploration project for unconformity-related uranium deposits was commenced in 1985 by PNC Exploration (Canada) Co. Ltd. The Paul Bay Ore Shoot was discovered in 1989 at the northeastern end of Yalowega Lake by a reconnaissance drilling targeting an electromagnetic conductor. The deposit is an inclined tongue-shaped ore shoot ranging from the unconformity between Aphebian basement and the Helikian Athabasca Group sandstones to the basement at least 140m below the unconformity level. An additional orebbdy named the Ken Pen Ore Zones was found in 1993. In total, geological reserves amount to about 9, 000 t U₃O₈ at an average grade of 3.2% U₃O₈.

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