A lineament is one of the most significant structural information in visual photogeological interpretation, and is usually extracted by means of recognition of diagnostic morphological features such as linear drainage flowpath.
This paper describes an approach for automatic extraction of lineaments from Landsat MSS data and makes appraisal between the lineaments by visual interpretation and automatic extraction.
Directional Segment Detection Algorithm (DSDA), which is different from conventional automatic extractionmethod, has been newly developed in this research. Analytical appraisal of the present results revealed that the majority of the lineaments by visual interpretation were automatically extracted. The reliability of the extraction mainly depends on tonal contrast expressed on the MSS image (band 7), length of lineament, and directional angle of lineament with respect to the sun azimuth.

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The Nurukawa deposit is of Kuroko type lately discovered in the northeastern extension of the Hokuroku district. The first discovery was made by surface diamond drilling in 1984 under thick cover of Quaternary pyroclastics about 2 km west of the lake Towada. An extensive exploration program has been carried out by combining construction of underground drifts and subsequent underground drillings.
The No. 5 and No. 3 ore bodies are now under exploration and exploitation. The characterisitcs of the deposit are nearly the same as those of known Kuroko deposits except its high gold content. It consists of polymetallic massive sulfide layer (black ore) and underlying silicified tuff breccia with network and dissemination of sulfides (siliceous ore). The siliceous orebody is classified into two types, namely, layered and stockwork, based on their shape and mode of occurrence. The latter type has cylindrical shape with a diameter of 20 to 40 meters and the vertical length of more than 50 meters. It has been revealed that gold content in the siliceous ore is extremely high especially in its core which ranges from 15 gram/ton to 100 gram/ton.
Gold and silver mineral in siliceous ore is identified as electrum which has 50-70wt.% gold and 50-30 wt.% silver. In layered and stockwork siliceous ores, the electrum is concentrated in the chalcopyrite-pyrite-quartz veinlets as tiny grains about 10 microns in their diameter. These veinlets occur both on the margins of sphalerite and galena-bearing sulfide veinlets and within breccias in sphalerite and galena-bearing silicified pyroclastic rocks.
Statistical analysis of assays on gold, silver, lead, zinc, iron, and barium (sulfate) in the siliceous ore indicates that gold has strong affinity with copper and iron. Whereas, lead, zinc and barium which represent the elements enriched in black ore show good correlation each other. It is concluded, therefore, that the gold mineralization took place prior to that of the black ore.

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The Tochibora ore deposits of the Kamioka mine are mainly composed of skarn type lead and zinc ore bodies which replace a part of tightly folded limestone beds.
The deposits are classified into four types; 1) pyrometasomatic lead and zinc deposit (so-called Mokuji deposit), 2) mesothermal replacement lead and zinc deposit (so-called Shiroji deposit), 3) silver deposit and 4) disseminated type lead and zinc deposit described in this paper.
Features of the disseminated type mineralization have been disclosed by recent exploration activities as follows;
(1) The mineralization does not appear in limestone but in Inishi rock and gneiss.
(2) There is a strong structual control of the mineralization by weak zones such as fold axis planes and intrusion boundaries of aplitic dykes. Directions and inclinations of ore shoots of the disseminated type deposits are not always concordant with those of the pyrometasomatic deposits.
(3) The disseminated type deposit consists of epidotized-chloritized ore and silicified-sericitized ore with a small amount of argentiferous silicified lens.
(4) Genetical stages of wall rock alteration recoginized by the sequence of mineralization are as follows; early stage: epidotization-chloritization of Inishi rock and gneiss,
late stage: silicification-sericitization of epidotized-chloritized Inishi rock and gneiss.
Studies of fluid inclusion, wall rock alteration and mineral assemblage on the Tochibora ore deposits including the disseminated type mineralization were useful to make a conceptual genetic model for the ore deposits.

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Power Reactor and Nuclear Fuel Development Corporation (PNC) of Japan has been undertaking the uranium exploration in Niger since 1981.
This paper introduces the Mini-Sosie method which was applied in this work during 1982 and 1984. About 200 km of survey lines in total has covered more than 1800 km². In the west region of the target area, at least two reflectors were found. On the basis of measurement of elastic wave velocity these reflectors were considered to be the lithological boundaries between lower limit of analcime-rich facies in Abinky Formation and sandstone in Tchirezrine 1 Formation, and between sandstone and mudstone in upper Izegouandan Formation. These reflectors enabled us to interpret the structure of the target area.
An on-site data processing system using the microcomputer was developed for qualitative check at camp. This system has the basic processing software including the synthetic seismogram. The system is capable of processing the data to check the possible failure in data acquisition process and is useful in determining the most suitable survey specification.

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The Mamut porphyry copper deposit in northwestern Sabah is genetically associated with adamellite porphyry which intruded into host serpentinite and siltstone. Adamellite porphyry intrusives were possibly derived from Kinabalu batholith. Copper-gold mineralization is observed in strongly fractured zones which are spatially related to the belt of northwesterly extending ophiolite complexes.
The first exploration activities at Mamut area started in 1965 with detailed drainage geochemistry by the UN Labuk Valley Project. The Mamut deposit was assessed for its grade and lateral extent based on the results of drilling by the Geological Survey of Malaysia, followed by further detailed systematic exploration and exploitation programs by the OMRD company of Japan. The mine has been in operation for 12 years since 1975 and is currently producing 500, 000 tons of crude ore averaging 0.56% Cu and 0.6-0.7 g/t Au per month.
The second phase of exploration commenced in 1984 in anticipation of additional ore reserves in the periphery of the deposit. The exploration pgrgram was worked out on the basis of ore target criteria, which were developed from the conceptual genetic model of the Mamut porphyry copper system as follows.
(1) Obducted slabs peeled off from the oceanic plate were thrust up from the Sulu Sea onto and into the geosynclinal sediments and then block-faulted by compressional stress of subducting plate.
(2) Regionally, adamellite intrusives structurally controlled by fault system were initially emplaced to a high crustal level. At Mamut, adamellite porphyry intruded preferably along the intersections of N-S and E-W trending faults. The intrusives introduced magmatic hydrothermal fluids, which subsequently produced an initial stage of quartz-biotite alteration and copper-gold mineralization.
(3) The magmatic fluids extended outwards from the intrusives and interacted with convecting meteoric waters, giving rise to quartz-sericite-pyrite assemblage mainly in host rocks.
(4) Granodiorite porphyry dikes were emplaced from south. Lead-zinc mineralization of calcite-quartz veins was introduced in association with hydrothermal fluids of waning stage.
The above tectonic style and proposed genetic model of the deposit are consistent with the tectonic history of ophiolite in Sabah.
The M1 area, a northern continuation of the deposit, and the bottom extension of the deposit were thus selected for final drilling targets. A total of 50 drill holes carried out during the period 1984 to 1986 have shown that ore-grade mineralization underlies, to a depth not less than 400 m from the original surface, the area of already confirmed mineralization and it extends as well to the north beyond the initially proposed pit limit. The newly-confirmed ore reserves are estimated to be 37 million tons with a cut-off grade of 0.35% Cu.

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