Transitions of mining technology of Japan after 1967, when the last special issue on Japanese underground mining technology was published, was scoped. During these years, Japanese mining industrieshave drasticallychanged, namely, the number of active metal mines decreased from 390 of 1967 to 57 of 1982, 27, 121×10³t to 6, 439×10³t of the metallic are production, and 43, 811 to 7, 599 of the number of workers employed in metallic are mines. While, non-metallic industries except coal and petroleum industries, particularly limestone quarrying had rapidly grown to the 180×10⁶t producible industry from the 65×10⁶t of limestone production in 1967 and now has experienced the hardly depressed years after the peak production of 178×10⁶t of limestone in 1980.
Since these years, the most remarkable change in mining technology is the mechanization which is typically shown in the broad applications of trackless mining system for underground and the rapid shifting from glory hole method, tunnel mining and other systems to a large scale bench mining method for open-pit.
Other sectors of technology, drilling and blasting, transportation, supporting, mine safety, system planning, and so on have also progressed, steadily. Japanese mining technology has still hold the higher level under the severe situations.

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It is fundamentally important to establish the stabilized supply of non-ferrous metals which are basic resources, in order to secure the stable growth of Japanese economy further and to let people enjoy their rich and comfortable lives.
Mining policy has, therefore, been carried out based on the basic idea which is to develop the domestic mineral resources systematically, as well as to promote the development of overseas resources actively.
In this paper, we wish to make clear the development of mining policy and to imagine what the mining policy should bein the future.

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The purpose of this paper is to describe mine safety policy for the last ten years in Japan (except coal and lignite mines). Mine safety is, in general, performed according to Mine Safety Law. Mine Safety Law, enforced in 1949, stipulates that the term “safety” means 1. Prevention of danger to man in mines, 2. Protection of mineral resources, 3. Preservation of mine facilities and 4. Prevention of mine pollution. However, “mine safety” is generally thought to have two aspects-to prevent danger to mine workers and to prevent danger to other people (e.g. mine pollution).
The number and rate of mine accidents have gradually decreased so far. However, since the accident rate and the intensity are still high compared with other industrial sectors, proper countermeasures are continuously required.
To prevent the danger to other people, there are two big problems: that are 1. accumulated environmental pollution from mines and 2. collapse of waste piles.
Accumulated environmental pollution from mines has a special character, e.g., there is a danger of a continuous occurrence of environmental pollutions even after closing of mines. This is different from other industries, and this makes it difficult to solve the problem.
MITI has promoted preventative action for environmental pollution from mines by means of subsidize, financing and R & D to establish a long term pollution prevention technique (undertaken mainly by Metal Mining Agency of Japan), etc.

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Toyoha mine is located on the south western area of Sapporo city, 43 km from the city center. The mine is one of the largest silver, lead and zinc mines in Japan. From 1915 up to 1982, it has produced 12 million mt of are containing 1, 400mt of silver, 300 thousand mt of lead, and 780 thousand mt of zinc. In the last half of 1982 the mine produced 221, 884 mt of are and o re grades are 148g/mt Ag, 2.39% Pb, 8.43% Zn, and 15.34% S.
The deposits are epithermal fissure filling veins. More than forty veins have been discovered. Vein width varies from several cm to over 10 m, generally 2-3m, and vein dip is 50 to 80°C. Main levels are driven at 50 m vertical intervals and bottom level reaches to 600 m depth from the surface.
The mining method is conventional sub-level stoping using slusher.
The area around the mine is also known as a prominent geothermal field. The maximum temperature of over 200°is obtained from the bore holes near the mine, and in the underground the rock temperature has become to 130°Cat a driving head. To lower the temperature at the working site, three main methods are being practised: 1) extensive ventilation system 2) cooling system by chilled water 3) dewatering of the hot spring before development.

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Jokoku Mine was discovered in 1936 and had produced mainly manganese ore. Since 1976, because of the big reduction of manganese demand, production of silver-zinc-lead are was begun. Now, controlling working faces and quarity, production iskept. Rising up productivity, we wish to make an effort to secure the domestic mineral resources.

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Kamaishi Mine is the only iron mine in Japan, and after the discovery of copper deposits, it also became well known as a distinguished copper mine, which is one of the typical pyrometasomatic are deposits in Japan. The annual output of total crude ore is about 900, 000 tons (wet). Sub-level stoping method is mainly adopted and both of room & pillar stoping method and cut & fill stoping method is also. Because of expansion of the track-less mining system, there are many self-moving equipments, those are Jumbos, L.H.D.s. dumptrucks, jeeps, etc. AN-F0 explosives usually are used for blasting of tunnelling and stopping. The main haulage is carried out by a 15 t trolley locomotive with radio control and twenty 12 t Granby-cars. Almost all amount of underground water is drained by gravity through the main levels. Because of many inlets and outlets of air, there are strong natural air flows in the mine. But many local fans provide fresh air in order to keep good condition. Today, the mine has many subjects to solve. The important one of those subjects is the recovery of the remaining pillars and the support of mined area.

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Hanawa mine is located on the border of Akita and Iwate prefecture in northeastern Japan.
The head office and the concentrator are reached by 6 km drive from Tayama station on The Hanawa Line of Japanese National Railway. To reach the mine office further 4 km drive is needed.
The mine was purchased by Kuhara Mining Co., Ltd. in 1920 and transferred to Nippon Mining Co., Ltd. in 1929. The mine had undergone several shutdowns and reopenings and has been operated by Hanawa Mining Co., Ltd. 100% owned subsidiary of Nippon Mining Co., Ltd., since 1973.
The mine is defined as Kuroko are deposit mine, of which deposits are in Shimokobezawa formation composed of volcanic and pyroclastic rocks of Miocene. Ore bodies are much variable and complicated in its massive to bedded form, tonnage and grade. A water bearing breccia zone is adjacent to the deposits.
Eleven are deposits have been found. Today Aketoshi, Tomei, Higashidaiichi and Tatsumi deposits are being mined and Onnataira deposit is under exploration.
The underhand cut and fill with artificial roof stoping method is employed entirely. Two men crew conducts drilling, bl asting, mucking and timbering work necessary for a stoping cycle. Dimensions of working face are 2.4m×2.4m or 2.1m×2.1m, Every mined out cavity is filled with cycloned mill tailings after 30-50cm thick, 10-20 cement mortar artificial roof is formed on the floor. TL-2 tire loaders and 5HP air slashers are used for mucking.
Ore and wastes are hauled by 2-4 ton locomotives and wound up in 3 or 2 ton skips through No.5 or No.3 shaft and then trucked to the concentrator and on the waste dump. Filling materials are also trucked from the concentrator to the slime plants at the mine site.
8, 548 tons, 93g/t Ag, 2.44% Cu, 1.43% Pb, 5.14% Zn and 16.2% S grade of are are mined in Feb., 1984.

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Namariyama mine is located in the lakeside of Lake Towada, in Kazuno-gun, northern part of Akita prefecture and produces the complex sulphide ore, “Kuroko”.
Production of the mine is 2, 000tons/month of crude are with a grade of 2.15%Cu, 5.41%Pb, 13.74%Zn and 19.56%S, and mining method is underhand cut and fill stoping.
This paper describes on the following points.
(1) Geology and mineral deposits
(2) Mining method.
(3) Transportation
(4) Ventilation, drainage, lighting and safety
(5) Problems on the operation and future planning

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南古遠部鉱山は, 秋田県鹿角郡小坂町に在り三菱金属 (株) により昭和35年12月鉱区開発工事に着工, 同38年5月から生産を開始した。
開発当初は, 第1立坑 (深度240m), 第2立坑 (深度215m) 間 (1, 300m) をOL坑道 (ASL125m) で結び, 第2立坑OLレベルより上方へ30m間隔で各鉱床との連絡立入坑道を開さく, 骨格とした (第2図参照)。
昭和44年には, 東又沢地区の開発に着工, 立坑 (深度180m) および2L立入 (700m) で大黒沢西部鉱床と連絡した。昭和51年7月, 三菱金属 (株) より新会社として分離独立し, 南古遠部鉱山となる。開発当初の可採鉱量, 昭和58年9月末現在総採掘出鉱量, 総探鉱延長および昭和58年度下期操業規模を第1表に示す。
山元には社宅等の福祉施設はなく, 従業員の大部分は36km離れた鹿角市花輪, 尾去沢から専用バスで通勤している。人員は第2表に示す。

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Kosaka mine is located at Kosaka, Akita Prefecture, about 22.3 kilo-meter east from Odate Station of the Japan National Railways. The mine site and Odate Station are connected in 34 minutes by the Kosaka Railway operated by Dowa. Kosaka has a population of about 10, 000 and most of them have relations with the mining activity of the company.
In this mining area, the Uchinotai and the Uwamuki deposits are operated. Current production rate is 37, 000 tons/month, and the average grade of the ore is 82g/t Ag, 1.05% Cu, 1.60% Pb, 4.80% Zn with a minor amount of Au and Ba. The Uchinotai ore deposits were discovered in June 1959, the development started in July 1960, and the production was commenced in July 1962. The Uwamuki ore deposits started the production in 1969.
These deposits, massive ore stratified, are typical Kuroko (black ore) deposits commonly found in the Miocene series of northern Japan. They consist of black ore, yellow ore, siliceous ore and gypsum ore. Recently many stock shaped orebodies with the network mineralization, have been found in the white rhyolite located below the Kuroko deposits.
Most of the ores are mined with the method of “The underhand cut and fill with artificial roofing”. Another mining method applied is “The drift type overhand slicing with pillars and back filling”, where trackless system with L.H.D. has been introduced. The mined ores, hauled in 1.2 cubic meter cars and crushed by the primary crusher, are transported by inclined belt-conveyors to the concentrator at the surface. For men and timbering materials, the Kakura and the Uwamuki Service Shafts are used.
In July 1983, the crude ore mined form the inception of the operation reached to 10 million tons.

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Matsumine deposit, located in the northern part of Odate basin, Akita Prefecture, is a large scale Kuroko deposit. This deposit was discovered in 1963. The development work was started in July 1964, and the production was started in October 1966, at the rate of 20, 000 tons/month. Current production rate is 40, 000 tons/month, and it is the largest copper supplier in Japan.
The Kuroko generally consists of black ore, yellow ore (cupriferous pyrite ore) and siliceous ore. The black ore (Kuroko) is a black coloured ore consisting mainly of sphalerite, garena and barite, and rich in gold and silver, too. The yellow ore is a yellow massive powdery ore comprising mainly chalcopyrite and pyrite. The siliceous ore which is rich in silica is divided into two types, one containing considerable amount of chalcopyrite and pyrite, and the other with a high sphalerite content.
The mining method applied is “The underhand cut and fill with artificial roofing”. Once a unit block of ore is mined out in a stope, iron reinforcing bars are laid on the floor, and a 15 percent cemented mortar mixed with mill tailings and volcanic ash is pumped over the bars up to 0.6 meter thickness. Then, the space above the layer is filled with the 3 percent cemented sand slime. This reinforced mortar serves as an artificial roof when ores below are mined next. In 1982, the conventional battery locomotive and tub system was partly replaced by the trackless system with L. H. D.

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Fukasawa Mine is located in Odate City, Akita Prefecture. The orebodies are typical stratified Kuroko deposits, and weredi scovered in August 1969. They lie in a steep mountain site at a depth of 400 meters, and extend over an area of approximately 1.5km×1.0km with a thickness of 5 meters. The production and exploration are being conducted by 130 company employees and 60 contractors.
The mine is operated with a fully trackless system. The mining method applied is “The underhand cut and fill with artificial roofing”. 22 drift headings are generally being worked on to produce 28, 000 tons/month of crude are with a grade of 0.89% Cu, 2.44% Pb, 8.39% Zn and 84.8 g/t Ag, and drive 250 meters/month of development drift. These drift drivings progress in cycles of drilling and blasting, mucking, and timber supporting. One of two parallel ramps with a length of 2.2 kilometers is used for the mine service. A conveyor for are and waste transportation to the surface is installed in the other ramp. Underground trucks are used for the transportation from local loading points to main are bins.
In the last few years, Fukasawa Mine has accelerated the reconstruction of underground facilities, the expansion of pro-duction rate and underground exploration work, as well as the development and modernization of its mining machinery. In addition to the scale up of loaders, compact cross-cut jumbos and timbering machines were developed in the mine. To take full advantage of these machines and improve the overall efficiency of the operation, a wireless communications equipment combined with a personal computer was installed in its underground operation in early 1983. The mining system based on the communications equipment has been called the Mine On-line System (abbreviated to MOS).

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Ezuri deposits are situated at the outskirts of Odate City. It takes 20 minutes by car to reach the mine office from Odate Station. The are deposits are distributed in the area of 500 meters east to west, and 2, 500 meters north to south. They belong to Kuroko Mineral Belt, and consist of black ore, yellow are and siliceous are like the other deposits previously discovered in this area.
The development work was started in October, 1977. The mine came into production in October, 1979 utilizing a fully trackless system, and has steadily increased the production rate from an initial 6, 000 tons/month to the present level of 10, 000 tons/month. Today, the grade of crude are is 155g/t Ag, 1.43% Cu, 2.8% Pb, and 7.8% Zn.
The mining method applied is “The underhand cut and fill with artificial roofing” combined with a trackless system.

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(1) 名称釈迦内鉱山株式会社釈迦内鉱山
(2) 所在地秋田県大館市釈迦内字二ツ森三八郵便番号017電話0186 (48) 2141
(3) 鉱種金, 銀, 銅, 鉛, 亜鉛, 硫化鉄鉱, 重晶石, 石こう
(4) 位置・交通釈迦内鉱山は, 秋田県大館市釈迦内字二ツ森38に事務所があり, 奥羽本線大館駅より国道7号線を北に約5kmの地点にある。(第1図)
(5) 地形・気候本鉱山は大館盆地北端部に位置し, 局部的に石英安山岩体よりなる丘陵が点在するほか, 概して平担であり, 地表の多くは耕作地となつている。
気候的には寒冷であり, 11月末-3月初旬は降雪期であるが, 積雪量は1m前後である。

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It is said that Hosokura Mine was discovered about 1, 100 years ago. At present it is operated under Hosokura Mining Co., Ltd., a subsidiary of Mitsubishi Metal Corp.
The production of crude are of Hosokura Mine reached its peak of 75, 000 ton/month in 1970, but now it is reduced to 33, 000 ton/month.
In former days only some parts of vein mostly consisted of galena were mined with over hand stripping method, and then shrinkage stoping method took the place of it. In 1957 sand slime cut and fill stoping method was introduced, because the stoping condition got worse according to the deeper working face. Further sand slime cut and fill descensional stoping method artificial roof of cement mortar has been adopted since 1975 in order to stope the are in weak rocks. Nowadays it is a main stoping method in this mine.

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Yatani mine is located in the Bandai Asashi National Park about 28km south west of Yonezawa city, one of the heaviest snowfall regions in Japan.
In 1956 Oppu Mining Co. subsidiary of Mitsubishi Metal Mining Co. constructed underground mill plant to overcome heavy snow and commenced full scale operation (mine production 3, 500t/month).
Since then mine production was gradually increased up to 10, 000t/month, but restricted by the capacity of mill plant and haulage shaft, recent mine production is about 9, 000-9, 500t/month. In 1978, Yatani Mining Co. succeeded to the mining operation from Oppu Mining Co.
Budgeted mine production for Oct. 1983-Mar. 1984 is 9, 000t/month of crude are with 2.70% Pb, 4.90% Zn, 0.70 Au, 40g/t Ag.
The Yatani deposits are epithermal vein type deposits situated in acidic tuff member of Yatani formation of Miocene age. Principal are minerals are sphalerite and galena with gold and silver.
Mining methods using in Yatani mine are mainly overhand cut and fill stoping considering variable vein width (2-15m) and rock conditions.

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Yaguki mine was developed by Nittetsu Mining Co., Ltd. as a copper mine after obtaining its mining concession in 1954.
Starting full scale mining in 1958, this mine has produced copper are until 1978. Copper are mining came to the end, but there exist substantial amount of tungsten ores. This mine has been operated as a tungsten mine since 1971.
The deposits are typical contact metasomatic ones of skarn type. The principal minerals are chalcopyrite, magnetite, pyrrhotite and scheelite.
Scheelite ore bodies tend to occur in the green skarn directly under limestone in a mass or disseminated form.
Depending on the size and occurrence of are bodies, the mine selects the sublevel stoping, room-and-pillar mining or slice-fill stoping method.
At present in a year about 20, 000 tons of crude ore are treated in the beneficiation plant.

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The outcrop of Seigoshi vein was discovered by Isamu Sakata in 1931, and developed by Chugai Mining Co., Ltd. since 1934. We are developing 60 meter Level under sea level. Seigoshi vein is hydrothermal fissure filling deposit with andesitic country rock, and it is crushed and clayey.
The stoping method was changed to the underhand stoping since 1968, from the old overhand cut and the fill method. The present method is the reinforced mortar roof-underhand-stoping and the top-slicing method. As a result, the efficiency increases by 60 to 80%, and it is better for mining safety by this improvement.
Because of much underground water at this mine (average total quantity of through the year, 45m³/min.), water is drained by submersible pump under 0 meter level, and muddy water caused by stoping and drifting is purified at the flocculate precipitator to prevent pollution from mining.
The present production is 1, 000t/month, its grade 14.2g/t-Au, 340g/t-Ag, and employees 39 workers and 9 personnels.

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茂住鉱は岐阜県の最北端, 吉城郡神岡町東茂住に位置する銀・鉛・亜鉛の鉱山である。当鉱発見の時代は詳らかでないが一説には養老年間 (約1200年前) といわれ, 天正年間 (約400年前) に鉱山奉行茂住宗貞により大々的に開発され盛んに金・銀・鉛を採掘したと伝えられている。明治7年三井の所有となり, 昭和25年三井鉱山から分離独立し, 三井金属鉱業 (株) 神岡鉱業所茂住鉱として今日に至つている。
茂住鉱の特色は鉱床規模が小さく緩傾斜 (45°～70°) で複雑な形をしているが比較的高品位 (Zn7～8%) である。採掘はほとんど通洞地並以上で行なつており, 自然条件を生かした重力による運搬系統, 自然排水, 自然通気を主力にしている。最近では通洞地並以下に重点をおき, その開発を行なつている。採鉱法は鉱床条件と上・下盤が脆弱であることからカットアンドフィル法を主力にしており, 種々の採鉱法の改善, 大型機械化, トラックレス化の全面的拡大によつて高能率な操業を行なつていることである。
昭和40年以降, 主な技術改善は運搬系統の合理化, 圧縮空気の高圧化, 坑内作業の機械化, 大型機械の導入とトラックレス化の拡大等である。採鉱法においてはメカナイズドカットアンドフィル法 (上向穿孔方式), 傾斜密充填採鉱法の開発, 近年はトラックレス化の拡大に伴つて密充填採鉱法 (水平穿孔方式) の確立で全ての鉱床を安全かつ高能率に採掘できるようになつた。
一方粗鉱生産量は新鉱床の発見と既知鉱床の下部延長の確認を背景として逐次増産し昭和50年には1, 800t/日を達成した。しかし53年には亜鉛の需要不振, 金属建値の暴落により粗鉱生産量1, 200t/日への減産と人員合理化を実施し今日に至つている。

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The Tochibora Mine, owned by the Mitsui Mining & Smelting Co., Ltd., is located at the central part of Japan, Gifu Prefecture. It is one of the largest zinc mines in Japan as well as in the world. The annual output of crude are is 950, 000 tons with average grade of Zn (4.3%), Pb (0.32%), Ag (22g/t).
Some of the features of the Tochibora Mine are as follows;
First of all, the orebodies are large in size and are generally hard and solid. Ore grade is comparatively low but distributed homogeneously. Secondaly, it does not need any special devices for drainage and ventilation owing to its favorable topographical condition. Thirdly, the first trackless mining system was introduced in 1968 in order to get high productivity. Moreover, the Tochibora Mine employs various mining methods, such as sublevel stoping method, induced block caving method and mechanized cut and fill method. Combining the trackless mining system with various mining method, a high productivity has been attained. This is also due to the introduction of huge machinery and reduction in man power of miscellaneous jobs.
In the past, the mine has faced several crises, that is, depreciation in metal prices, depression in demand for zinc and escalation of operating cost. Under these circumstances, we had no choice but to reduce the daily are production to 3, 200 tons, even though it once had achieved 4, 800 tons per day in 1974.
Recently, we have just finished to form a long-range plan based upon the past experiences. Its framework is to yield excellent and small are deposits proportionately and to establish a stable operation toward a fluctuation in prices.

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Nakatatsu Mine, which is located nearly in the central part of Honshu Island of Japan, is a lead and zinc mine, where pyrometasomatic lead and zinc deposits in skarn masses have been mined.
The annual output of crude are in this mine is 410, 000 tons with the average grade of 25 grams per ton silver, 0.38 percent lead and 5.38 percent zinc respectively.
The lead and zinc concentrates prepared here are processed at the smelting and refining plants of Mitsui Mining & Smelting Co. Ltd. In 1973, a trackless mining system was introduced into Nakatatsu Mine and to secure more increase in are production, various improvements for the mining facilities such as streamlining its transportation network and various large-sized rock drilling machines were also carried out.
Basing on such improved technologies, a mechanized cut and fill method was employed and as a result, the total efficiency per man-month has risen to 227 tons in 1982 from 189 tons in 1973.

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The Akenobe Mine is located in the central part of Hyogo Prefecture some 150km west from the ancient capital of Kyoto. Access is by highway from Himeji city on the Pacific side and from the town of Yohka, where is the nearest National Railway station on the San-in Line.
The history of the mine goes back to the early 9th century when the first discovery of the deposit was reported. Modern mechanized operation was commenced in 1896 under the management of Mitsubishi with the introduction of a western technology.
Since cassiterite in the are was found in 1909, the Akenobe Mine has been in operation as a leading tin producer in Japan. The total are mined to date is estimated to 16 million tons with average grades of 1.01% Cu, 1.48% Zn, and 0.41% Sn
The Akenobe deposits are of typical polymetallic xenothermal vein-typeproducing tin, tungsten, copper, zinc, silver and gold. More than are hundred veins are distributed in the area of about 9.0km², with a vertical extension of 1, 020m. The distri-b ution of are minerals shows a remarkable zoning with age.
In the underground mining, cut-and- fill stopirig method is adopted and mill tailings are used for backfill in the stopes. Waste rock from the cross cut is also used in some areas where waste is hard to hoist up to the surface.
Recently trackless mining has been introduced to the new development work in Chiemon area.

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Yanahara Mine is located in Kume-gun, western part of Okayama Prefecture, and produces iron sulfide ore. Total annual production is 132, 000 tons of crude ore. The number of mine personnel is 92 in all, and separated to two divisions; the mining division and the administrative service division. The mining division consists of four sections; mining, maintenance, concentra-tion and water treatment. The operations are proceeded in day shifts.
The orebodies are bedded deposits, and their main iron mineral is a high grade pyrite. They lay in volcaniclastic rocks and slate of permian. The hanging wall is slate and the foot wall is diabase and quartz-diorite. The orebodies extend in an area of approximately 2, 000m×400m with an average thickness of 60 meters.
Yanahara Mine has two main shafts. One is used for mine service, another is used for ore transportation. Level drifts are generally located at 15 meter intervals from L+6 to L-60, while several sublevels are prepared among them. The orebody being mined is divided into the northern block and the southern block. A central pillar runs between them from east to west. The mining method applied is a sublevel stoping, and the mined space is filled with waste rocks. The primary stoping has been finished, and regular band pillars are currently being mined.
All the ore mined are crushed by a jaw crusher located at L-32, and wound up through the shaft to the gravity concentration plant. To meet the market's needs, the concentrates are classified to several brands according to their size and grade. The main usages of products are high grade iron oxide, sulfuric acid and heavy concrete.

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(1) 名称 都茂鉱業株式会社都茂鉱山
(2) 所在地 島根県美濃郡美都町大字山本イ2, 183の3
(3) 鉱種 金, 銀, 銅
(4) 位置・交通 鉱山は山陰本線益田駅の東南約20km, 益田～広島を結ぶ国道191号線に沿つて位置し, 益田駅より事務所所在地まで定期バスが運行し, 交通はきわめて便利である。
(5) 地形・気候 鉱山付近は海抜約260～500mで, 中国山地特有の起伏ある山々に囲まれたところにある。
気候は冬は北西の風が強く, 曇の日が多いが, 春, 夏, 秋は温和である。

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The Kuga mine are located at Negasa, Mikawa Town, Yamaguchi Prefecture, started the operation in 1953, treating the production of 2300 tons tungsten-copper are per month. Monthly production are approximately 15 tons of scheelite concentrate, 3 tons of scheelite-cassiterite mixed concentrate, 90 tons of copper concentrate.
The geology of the mine is underlain by the Triassic Kuga Group which consists of slates, cherts, sandstones and limestones. The are bodies are tungsten-copper deposits of a contact-skarn type which is controled by the structure of the anticlinorum and the synclenorum. The mining methods are breast stoping and sublevel stoping. The transportation is track method used battery locomotive. The ventilation and the drainage methods are almost native. The number of underground artisans are 18 and they are all contracted men.

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Fujigatani mine is located in Kuga-gun, eastern part of Yamaguchi prefecture and its deposits are skarn type.
Production of the mine is 1, 650 tons/month of tungsten are (0.95%WO₃) and mining methods are 1) open stoping with pillar supports and 2) underground cut and fill stoping.
This paper describes on the following points
(1) Geology and mineral deposits
(2) Mining methods
(3) Transportation, drainage and ventilation
(4) Problems on the operation and future planning.

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Kushikino gold mine is one of the largest gold-silver mines in Japan. The mine consists of two pits -Kushikino and Iwato pit.
Kushikino pit is located on the northwestern coast of the Satsuma Peninsula and forms part of the southwestern Kyushu gold field. The are deposits consist of more than 30 epithermal veins formed in andesitic volcanic rocks of Miocene age. At present the mine produces 180 ton per day of crude are with 5.3g/t of gold and 47g/t of silver. Underground cut and fill is employed and the mining stopes are situated between 60m above and 280m below sea-level
Iwato pit, which is located some 70km south of Kushikino pit, is noted for its unusual massive gold mineralization, termed ‘Nansatsu type’. Ore deposits in the pit consist of gold are shoots in a gold- and silver-bearing silicified mass that occurs in andesitic volcanic sediments called the 'Nansatsu Group'(of probable Miocene age). At present Iwato pit produces 420ton per day of are (gold grade, 3.3g/t; silver grade, 6g/t). The are is mainly produced from a small open-pit.
A total of 110ton of ore, containing 95% silica, is sent daily to the Hibi copper smelter of Mitsui Mining and Smelting Co., Ltd., as a silica flux for the copper smelting process. The balance of the crude are is sent for treatment at the Kushikino cyanidation plant.

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Kasuga mine is located at Makurazaki city, southern part of Kagoshima prefecture and its deposits are massive silicate are containing gold and silver minerals.
Annual production of the mine is 76, 000 tons of crude are (2.3g/t Au) and mining method is bench cut.
This paper describes on the following points
(1) Geology and mineral deposits
(2) Mining operation 1) opening, 2) underground mining, 3) bench cut mining, 4) operation practice
(3) Others 1) crushing, 2) transportation

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Tsukinuno mine is located in the central part of Yamagata prefecture.
Annual production of the mine is 100, 000tons of bentonite are which consists of Na-montmorillonite accompanying with a little amount of quartz, feldsper and calcite and mining methods are shrinkage stoping and sublevel stoping.
This paper describes on the following points
(1) Geology and mineral deposits
(2) Opening
(3) Mining methods
(4) Others 1) transportation, 2) ventilation, 3) drainage, 4) lighting, 5) mine safety

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The Hiraki mine is situated in the southeastern part of the Hyogo prefecture, about 50km to the northwest of Osaka. Hiraki deposit is a large hydrothermal kaolin deposit in Japan, output of which is 5, 000-6, 000 tons/month. And Hiraki-Kaolin is mainly used for chinaware and glass-fiber.
In the recent ten years, trackless underground mining have been adopted in Hiraki mine. Among underground mining methods, sublevel stoping, room and pillar method with underhand stoping supported by the rock bolts are working, and then mechanized cut and fill supported by the cable bolt is working too.
This paper is described the underground mining method at Hiraki mine, under the following items.
1. Sublevel stoping method.
2. Underhand stoping supported by the rock bolts.
3. Mechanized cut and fill.
4. Measurements on the effect of rock bolting.
5. Adopting reasons of cable bolting.
6. Past records and Effects of cable bolting.

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Yaguki mine was developed by Nittetsu Mining Co., Ltd. as a copper and limestone mine after obtaining its mining concession in 1954.
Starting full scale mining in 1958, this mine has produced limestone for many uses. In July 1974, production of limestone powder was started.
Geology in the district is composed of sedimentary-metamorphic rocks as limestone, slate and schist and intruding igneous rocks. Limestone bed is distributed 1, 200m EW and 1, 300m NS, and 100m in thickness.
The mining of limestone is carried out in underground by the sublevel stoping method. In a standard case, slots and sublevels are driven into a block that has been by providing 20m wide vertical pillars at intervals of the center-to-center distance of 40m; long holes are drilled from around the slots in order and the block is blasted to be stoped. The blasted limestone is led to a breaking chamber through a draw hole and broken with a breaker; it is then thrown into a chute, where it is loaded on to mine wagon.
Limestone is broken, crushed, then pulverized with a roller mill into certain sizes. It is mainly used as a filler for road paving work and for industrial use. Its annual production amounts to about 50, 000 tons. Furthermore, high-grade limestone powder has been supplied to thermal plant since 1983, shipment of 6, 000 tons a year.

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Musashi-shiraiwa mine is a underground mining limestone mine which is located at naguri-mura, western part of Saitama prefecture.
Annual production of the mine is 170, 000 tons of limestone are and mining method of it is sublevel stopping.
This paper describes on the following points
(1) Outline of the mine 1) location, 2) development, 3) geology and mineral deposits, 4) motive and changes of adoption for underground mining method
(2) Opening 1) pre-surveying, 2) plan of opening, 3) norm for structure of are brock, 4) operation of drifting
(3) Mining methods and operation
(4) Transportation
(5) Ventilation
(6) Transmission

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The Sanpo mine is located in the north-west of Okayama prefecture and about 15kms to the west apart from Bittyu Takahashi station of the Hakubi railroad line.
The geology around the mine consists of the limestone, the conglomerate rock and the andesite group et al. The deposit, whose shape is massive, is the noncrystalline limestone. Recently, about 15, 000 tons of the are are mined per-month and the quicklime and the slakedlime are produced from them.
The are is mined by the sub-level stoping method and transported by the battery locomotive & granby car.

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The Kanahira mine is located in the border of Okayama and Hiroshima prefecture and about 33kms to the west apart from Bittyu Takahashi station of the Hakubi railroad line.
The geology around the mine consists of the limestone, the Liparite group and the granite porphyry et al. The deposit, whose shape is massive, is the crystalline limestone. Recently, 9000-10000 tons of the are are mined per month and the ‘Kansuiseki’ and the ground limestone are produced from them.
The are is mined by the room and pillar method and transported by the trackless method.

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Isa limestone quarry with an annual production capacity of 18 million metric tons belongs Isa cement factory which constitutes a mainstay of Ube Industries' cement division.
The limestone produced from this quarry is of non crystalline having an excellent quality standard, therefore 40% produce is supplied to iron & steel making and chemical industries. The other 60% is used for the cement raw material.
Already, 2.1 hundred million metric ton limestones have been excavated from this quarry since it's installation in 1946.
From the point of view to prepare lasting limestone supply in future, we had been working since 1978 on the development of a new limestone deposit and had completed its development in 1981.
Considering the topographic features and the prevention of traffic pollution, it has been decided to adopt a belt conveyor system for the 3 km hauling of limestone produce from the new quarry, which has 2 underground shafts connected to the bench on the top of the mountain, to existing secondary crusher plant.
At the bottom of each shaft, there are installed a rockbreaker room, an are bin, and a primary crushing chamber, in which all machine are operated from outside the shaft about 1.5 km away by using T.V. and microphone.
With the completion of the works for the installation of above described equipment and facilities, all systems for the long-term stable supply of limestone which had been the original object of this limestone resources development project have been established, and thus the raising of mining efficiency, prevention of environmental pollution, etc. have been achieved as originally planned.

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The Torigatayama limestone quarry is the most up to date and large scale quarry in Japan, located in Shikoku island, Kouchi prefecture. However the annual production capacity has been increased successively to 10Mt, 1983's annual production rate fell sharply than its capacity due to the depressed state of the Japan economy.
The operation is separated into two locations, Niyodo village and Susaki city. The quarry and the primary crushing facilities are in Niyodo village, and the processing plant and the ship loading facilities are in Susaki city. Both processing plant and primary crushing facilities are connected by the long distant belt conveyor of 23km long with the belt speed of 300m/min, of which 92% is installed in the underground.
The Torigatayama quarry has adopted the bench cut with vertical shafts system. The quarrying area has been getting wider to 0.8km² now and the elevation of the top bench is 1340m above sea level.
The production has started on May of 1970 after two years development work. Since then the accumulated production of 100Mt was achieved on Nov. of 1983. Roughly speaking, 50% of the products are sent to the steel makers, 30% to the cement makers, 10% to the construction works and the rest of them are shipped abroad.
The limestone are deposit is occurred in the Chichibu formation and it is covered by thin top soil of less than 1 m and has intercalation of the schalstein along the strike in the northern part of the are deposit. The minable are reserves are estimated around 1500Mt.
The climatic conditions at the quarry site may be characterized by the thick fog in the spring and the early summer, the heavy rain fall of around 1500mm monthly in the summer and the early autumn, and the cold weather of which temperature goes down sometimes 20°C below zero and the snow fall of more than 1m deep in the winter.
The detailed description of the operations are given as follows.

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Mt. Buko, elevation 1, 336m (now 1, 304m), is located at the western part of Saitama Prefecture near Tokyo, and the majority of its mass consist of limestone. The mountain is well-known for its limestone production as well as for its scenic beauty and as being a place of historical interest.
Three mining companies have concessions for mining limestone, and four mines are now in operation. The three mining companies are Chichibu Cement Co., Ltd., Buko Mining Company of Nihon Cement Group, and Ryoko Lime Industries, a part of the Mitsubishi Mining and Cement group.
Heretofore, all of these companies were mining independently, without co-operation, within their respective mining areas, which start from the mid-slopes of the mountain. However, 10 years ago the co-operative development project was envisaged by the companies in order to realize efficient and rational development.
In carrying out this project, technological studies, environmental assessments, and negotiations were made for the purpose of finding solutions to possible hindering problems.

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The Mamut mine which is the first porphyry copper type mine in Malaysia started its open-pit mining in May 1975. The mine is managed by Overseas Mineral Resources Development (OMRD) Sabah Bhd, a joint venture company organized by and between Malaysia and Japan.
To support this project, Mamut Mines Development Co., Ltd.(A consortium of seven major Japanese non-ferrous mining and metallurgical firms) was established in Japan, and has been engaged in sales of concentrates as well as offering fund and technology assistance.
The Mamut mining operation had to adopt the multi-stage narrow bench system under such situations as (1) steep topography, (2) the are deposit being incised beneath a high hill, (3) necessity of blending the various kinds of crude ore, (4) much rainfall, (5) reduced amount of pre-stripping due to depressed initial costs and so forth. As a result, the operation needed small and medium mining equipments which had high mobility. The actual work was carried out mainly by combining wheel loaders and 40T-45T dump trucks.
We could overcome the various difficult problems encountered at the initial stage, and the current operations is in good progress on 500th. T/month are and 610th. T/month waste basis.

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Huanzala is one of few mines that Japan developed successfully in forign countries. It is located among the Andes of Peru, about 4, 000 meters above the sea level, was opened at the year of 1968. It products the concentrates of zinc, lead and silver, treating 950ton per day crude ore.
Recently new veins at “El Recuerdo” Zone, situated about 2 km north of original zone, were developed. Because of the dimensions of new veins are very large and the grade is specially high, they were developed in short time and already reached to the production level of more than 500ton per day. Also they are located in short distance from surface, so we can enter to working place by vehicles directry through access tunnels and ramps for trackless machines.
Here in Huanzala mine, we adopted the most advantaged “mechanical cut and fill mining method”. The greater part of ores are dumped to main are pass by load haul dump machine, and later transported to mill plant by train. Another part of ores are transported by dump trucks through surface load.
About ten years ago we adoped small scaled trackless mining method with HST-1A, and recent years scaled it up to promote to one of modern mines.

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Akouta underground mine extracts the uranium deposits lying practically at a level at the depth of 250-270 meters.
The opening of mine was made by a slope composed of two parallel gallerys inclined at 20%, of about 1, 300 meters length.
The mining method is the room and pillar method using L.H.D. system.
In the first phase, the room are drifted in a checkered pattern with a width of 6 meters, leaving the square pillars with a side of 18 meters.
A cycle of drifting operations is drilling by a two-arms-jumbo mainly using diamond auger bits, blasting with dynamite and millisecond delay detonator, loading and carrying off of blasted are by a loader-hauler, falling of loose rock by a jumbo with pick and roof bolting by a special jumbo.
At the second phase, the pillar is mined by separating it in three working faces with a width of 6 meters by length of 18 meters, after packing the goaves of rooms and mined pillars. The packing is made by pushing in the pasty mixture of rubble, sand and a small quantity of cement by a concrete pump.
The ores are sorted out by their grade by measuring the radiation of ores in a bucket of loader 7 hauler at the point of charge of the belt conveyer.
In order to keep the personal exposure within the limits of permissible dose and to avoid the gathering at the year-end of the miners who have to work out of the active areas, a program extrapolating the exposure of coming months of each person was developed.

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In order to solve the water pollution problems at abandoned Matsuo sulpher-pyrite mine, the Japanese Government, the Iwate Prefectural Government and their concerning organizations have taken such measures as water sealing by plugging at the lowest portal level, construction of water way partially diversing surface water, reclamation of abandoned open pit etc., since 1970.
Among these measures, installation of the new neutralization plant, which is the major project for treating acid mine drainage from the mine, had been commenced in Aug.1977 and completed in Nov. 1981.
The plant is the newest and largest plant treating acid mine drainage in Japan, and its construction cost was approximately 9, 300 million yen.
The plant includes a bacterial oxidation system for converting the ferrous salt contained in the drainage to ferric salt prior to neutralization.
It enables the neutralization by calcium carbonate, resulting in a considerable saving of the treatment cost of acid mine drainage at the mine.

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