1. Sized products of the lead concentrate are briquetted, polished and analized statistically under the microscope. Mineral composition, and "free" and "locked" relationships of each mineral have been determined. From the result obtained, it has been concluded that to improve the grade of the lead concentrate it is necessary, to depress the "free" sphalerite and pyrite more effectively, because these minerals are in part flótated unduly in the lead circuit as "free" grains, not locked with galena. To improve the recovery, it is advisable to avoid overgrinding which increases the loss in grains of slime size.
2. Distribution of the silver in each base metal sulphide has been determined by dithizon. The most important silver carrier is galena, and some of the galena grains which are more argentiferous than others include minute specks of silver sulphoantimonide such as pyrargyrite and polybasite. Sphalerite and pyrite are also argentiferous, so it is impossible to concentrate all the silver by improving the lead concentrate from which silver is recovered.

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1. Sized products of the lead concentrate are briquetted, polished and analized statistically under the microscope. Mineral composition, and "free" and "locked" relationships of each mineral have been determined. From the result obtained, it has been concluded that to improve the grade of the lead concentrate it is necessary. to depress the "free" sphalerite and pyrite more effectively, because these minerals are in part flótated unduly in the lead circuit as "free" grains, not locked with galena. To improve the recovery, it is advisable to avoid overgrinding which increases the loss in grains of slime size.
2. Distribution of the silver in each base metal sulphide has been determined by dithizon. The most important silver carrier is galena, and some of the galena grains which are more argentiferous than others include minute specks of silver sulphoantimonide such as pyrargyrite and polybasite. Sphalerite and pyrite are also argentiferous, so it is impossible to concentrate all the silver by improving the lead concentrate from which silver is recovered.

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Surveys and studies on geology, ore deposits and structural control of. large numbers of. worked-outmetal mines of Japan have been conducted within the last few years by mining geologists attached to the industry, universities, geological survey, and similar organizations to such an extent of exactness and minuteness incomparable to those undertaken in the past. As a result, the mining geology of Japan, has like that of the United States begun to show composite and comprehensive progress in regard to thorough ness and preciseness.
The overall actual result of exploration and devlopment in Japan for 1950 reveals that though falling short of the prewar record, level exploration reached as much as about 240 kilometers and is heading yearly towards increase. while in boring, rapid spreading was shown as a consequence of improvement in its technique and reduction of cost, the total length for which reached as much as about 60 kilometers.
During the past year, new ore deposits worthy of note were discovered in mines such as Konomai, Numanoue, Shimokawa and Yoichi in Hokkaido, Kamikita, Tsuchihata and Matsuo in East Japan, Kune, Kamioka and Myoho in Central Japan, Akenobe, Ikuno, Yanahara and Kawayama in West Japan, Besshi and Okuki in Shikoku, and Kusu and Taishu in Kyushu.
The total amonht of ore devloped for the whole country for the previous year marked only a slight excess over that of mining in the case of gold and copper ores, but as for lead and zinc ores it showed about 3 times the amount mined while for sulphur and pyrite ores, we were able to achieve about 6 times the amount.
The total amount mined during last year was only 50% of the prewar maximum, but by decreasing the amount of crude ores, we succeeded in improving their grades and hence, if compared with that of the year before last, rapid improvements were seen on all lines.
This year, incentives for encouraging exploration have been granted by the Japanese Government to 339 mines for conducting their exploration tunnels and borings, to 21 mines for their geological surveys, and to 20 mines for their geophysical surveys. In addition to these, geological surveys of 78 mines will be undertaken by and at the expense of the Geological Survey Institute. Besides the foregoing, it is expcted that a fairly large number of surveys will be performed by various companies and survey set-ups attached to universities and similar organizations, which means that abuot 200 mines will undergo modern geological survey during this one year. Such an active and lively ore deposit exploration has never been witnessed in the past mining history of our country.
The mines now operating, including the ones under exploration, count as much as 900 for metallic and 1, 100 for non-metallic mines. Furthermore, due to the metal boom, the number of idle mines reopened is increasing monthly.

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Mining geology is an application of geology to mining. Its main object is the finding of ore, the prediction as to the persistence of ore in depth, and the appraisal of ore bodies.
The improvement of prospecting methods depends upon the progress of mining geology.
In recent years, the mining geologists in Japan have been doing fine work in discerning guides to ore.
Hereafter more emphasis should be laid on the use of contour methods of revealing ore structure, a closer investigation of faults, and the determination of temperature of deposition of minerals in ore deposits.

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This is an address in which the major problems of geology and mineral resources of India are summarized.

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