The Kamaishi mine is of skarn type and composed of several copper and iron ore deposits. The copper deposits except the Tengumori deposit are all emplaced in the skarn zone developed at the contact between a Carboniferous limestone formation and the Ganidake igneous complex of early Cretaceous in age.
It has been disclosed from the present study that the area of the Tengumori copper deposit is underlain by a Permian formation which is covered unconformably by lower Cretaceous sedimentary piles probably of preore in age. The Tengumori deposit is emplaced within a skarnized lenticular limestone bed situated at the upper part of the Permian formation. Lithological and mineralogical zoning observed at the deposit is as follows: limestone/pisolitic garnet/clinopyroxene-chalcopyrite/epidote/sedimentary rocks, in stratigraphically ascending order.
In this mining district, none of such copper deposit as emplaced within Permian limestone has ever been known. The present finding would thus provide a new significant exploration target to prolong the mining life of the Kamaishi mine. Calculated ore reserve of the Tengumori deposit is about 340, 000 tons with Cu 2.1% and is expected to increase considerably.

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Mode of occurrence of silver in the Nakatatsu skarn type deposits has carefully been studied in terms of microscopic observation and electron microprove analysis. The results reveal that silver is concentrated in galena and some other sulfides of the system Pb-Bi-Ag. The silver-bearing minerals are classified as follows on the basis of their grain size and silver contents.
Galena A: fine-grained galena with high silver contents (0.93%Ag in average) included in aggregates of sphalerite and pyrrhotite
Galena B: coarse-grained galena with low silver contents (0.23%Ag in average) occurring in general as massive aggregates
Pb-Bi-Ag sulfides: fine-grained crystals with high silver contents (3.95%Ag in average) in aggregates of sphaler-ite and pyrrhotite.
On the other hand, from the economic viewpoint, lead-zinc ores of the mine are conventionally grouped into three types as follows.
Low Ag/Pb type ores (Ag/Pb: 0-59)
Intermediate Ag/Pb type ores (Ag/Pb: 60-239)
High Ag/Pb type ores (Ag/Pb: ≥240)
The low Ag/Pb type ores are characterized by the presence of the galena B, the intermediate Ag/Pb type by the galena A and the high Ag/Pb type by the Pb-Bi-Ag sulfides.
In the deposits are well developed the zonal distribution of the above ore types, i.e., high Ag/Pb type→intermediate Ag/Pb type→low Ag/Pb type, from the inner skarn zone near the quartz porphyry mass towards the outer limestone side. The regularity of this zonal distribution has been employed not only as a practical indicator to increase the recovery of silver during milling processes but also as a promising guide for prospecting works to acquire economically favorable ores.

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Promising exploration margins around known kuroko deposits can well be evaluated in terms of the Na₂O anomaly reported previously (HASHMOUCHC et al., 1981). In the present study, using 662 samples from 61 drill holes in the Fukazawa mine area, an attempt has been made to figure out statistically the metallic contents and their variations in the footwall mineralization zone, which is essentially included within the promising margin delimited from the Na₂O anomaly. The results obtained are as follows.
1) Two economically significant thresholds in metallic distribution can be set at Cu 0.07%, Pb 0.18% and Zn 0.29% as a lower limit and at Cu 0.5%, Pb 1.4% and Zn 3.1% as a higher one.
2) The anomalous zones delimited by the lower thresholds are about two times as large as the presently known deposits in scale and are quite similar to them in both distribution and shape.
3) The higher thresholds obtained are virtually the same as the experiential cut-off values for the "siliceous ores" of the mine.
4) The "siliceous yellow ores" and the "siliceous black ores" appear to be different in their spatial distribution. The former tends to be predominated in the central portion of the mineralization zone and the latter in the peripheries of the zone.
5) The footwall mineralization zone thus defined extends rather regionally along the NW-SE direction, which is in harmony with what are given from our knowledges of magnetic susceptibility anomaly, alteration zoning and distibutions of so-called "Fe-chert" and post-ore basalt flows.

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In studies of kuroko ore genesis have to be equally taken into consideration the following two aspects, i.e., initial formation processes of ores and their modification processes during subsequent geologic history. Our careful observations on the mode of occurrence of the Shakanai deposits, which are essentially a continuation and extension of our recent works (KUMITA et al., 1980; KAMBARA et al., 1982), have disclosed some geologic key factors or conditions responsible for their formation and subsequent modifications. Important conclusions derived from the present study are as follows.
1. Environmental constraints on ore formation: The Shakanai deposits are suggested to have been formed at the "calm" local sedimentary deeps with no significant supply of clastic materials in space and within a certain period during which no significant volcanic activities took place in time. The assumed local sedimentary deeps are considered to be most likely due to the complicated submarine configuration of the pre-existing dacitic lavas.
2. Mechanical modifications of ore deposits: The ore deposits formed have undergone a variety of mechanical modifications mainly due to the intrusion of post-ore dacites, some deposits having been significantly dislocated and broken into several minor orebodies. Some of the footwall dacites, which are currently assumed to be of pre-ore and closely related with the mineralization, are also considered to have been involved in the mechanical modification processes of the deposits.
3. Chemical modifications of ore deposits: The deposits have also undergone a variety of chemical modifications both in quality and in quantity throughout their burial history, which are mainly due to possible multiple interactions with some "fluids" derived from different sources such as magmatic fluid, interstitial formation waters, and circulating seawater and/or meteoric water.
4. Preservation of ore deposits: For the good preservation of a deposit, the possible interactions with "fluids" as suggested above have to be reduced to the minimum. For its purpose, therefore, it would necessarily be concluded that some impermeable rocks against the "fluids" (i.e., compact igneous rocks or mudstone) must exist at the footwall side of the deposit as well as at its hangingwall side.

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The vein-deposits in the Akenobe mine have been cited as one of the best-known examples of the polymetallic vein-type mineralization with the characteristic of the remarkable mineral zonings. They occur in formations of slate, basic tuff and basic lava of middle to late Permian Maizuru Group.
The total amount of crude ores ever produced is estimated more than 13, 000, 000 tons (Cu 1.09% Zn 2.0% Sn 0.37%) from over a hundred veins, about 30 veins of which are still workable. Recent production and exploration tend to be moved to lower and outer parts of mineralized area. It is recognized that mineral zoning pattern which has been identified in upper and central parts of the area is still applicable.
The Shirogane veins, located at the southeastern fringe of the mineralized area, are proved to be:
(1) rich in Pb-Zn at near surface and upper part of the veins, on the other hand, rich in Cu-Zn at lower part;
(2) composed of two veins intersecting each other, Shirogane No.1 vein and Shirogane No.2 vein, the former at the lower part showing the precipitation from the ore solution rich in Cu-Zn and the latter from the ore solutions rich in Cu-Zn firstly and rich in Zn secondly;
(3) zoned vertically, Pb-Zn—Cu-Zn—Cu-Sn zones in descending order, however, vertical interval of Cu-Zn zone seems to be longer compared with that of average Cu-Zn zone in the Akenobe mine.
Adding those findings, it is also confirmed in Shirogane No.2 vein that ores are brecciated by fault displacement occurred in the period between the first Cu-Zn rich mineralization and the second Zn rich mineralization, and that ore-breccias are generally rimmed and cemented by quartz and sphalerite precipitated from later Zn rich solution.

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On the purpose of uranium exploration in the northern Saskatchewan in Canada, many kinds of geophysical survey were systematically conducted in the same surveyed area, and the geophysical data were integrated and interpreted to obtain the geological information.
The surveyed area is so-called the Athabasca area and has no outcrop. The basement rock composed of the Archean granite and the Aphebian metasediment are covered by the thick Athabasca formation and glacial deposits.
The basement structure assumed by the integrated interpretation well corresponded with the results of diamond drilling, suggesting that the systematic geophysical survey and the integrated interpretation are important and indispensable to obtain the information on the deep concealed geological structure.
In these years, the target of mineral exploration is mainly blind deposit and the necessity of geophysical servey becomes greater. Herein, this paper was presented as a successful casehistory of the systematic geophysical survey and the integrated interpretation on the deep concealed geological structure.

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