著者

山口 梅太郎 宮崎 道雄

出版者

一般社団法人 資源・素材学会

雑誌

日本鉱業会誌 (ISSN:03694194)

巻号頁・発行日

vol.86, no.986, pp.346-351, 1970-05-25 (Released:2011-07-13)

参考文献数

15

被引用文献数

5 9

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There has been a rapid increase of interest to unconventional methods of fracturing rocks.Particularly, mechanics of thermal fracture, either by the application of direct heat or electrothermal conversion, are most favourable for practice.In this paper, the authors reported their experiments to measure the strength changes of rocks heated to high temperatures and the thermal fracture.From the experiments, several fracturing mechanisms of rocks heated to high temperatures were found. Which are;a) Thermal elastic stresses induced in rock.b) Transformation of crystal form of the constituting minerals of rock.c) Decomposition of the constituting minerals.d) Melting.e) Thermal expansion of the constituting minerals.f) Others.Neverthless these mechanisms are all affecting to thermal fracturing of rock, one of them is a dominant factor to fracture a particular kind of rock by heat, for example b) to granite and c) to limestone.

著者

下村 弥太郎 山口 梅太郎

出版者

一般社団法人 資源・素材学会

雑誌

日本鉱業会誌 (ISSN:03694194)

巻号頁・発行日

vol.81, no.921, pp.68-74, 1965-02-25 (Released:2011-07-13)

参考文献数

7

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Prilled ammonium nitrate manufactured in this country has been applicable for AN-FO blasting. This paper is the second report of fundamental studies on AN-FO blasting using the recently improved prilled AN. The studies were consisted of experimental AN-FO blasting tests in a mine formeasurements of the cap-sensitivity and the detonation valocity and laboratory tests of loading AN-FOto bore-holes by an ejector type AN-FO bore-hole charger.AN-FO tested was more cap-sensitive in comparison with the AN-FO reported in the first report. Two bound No.6 blasting caps had a possibility to ignite 94 a 6 AN-FO charge in a sealed steel stube. Detonation velocities of AN-FO measured by Dautorich method were from 2, 0000 to 3, 000m/s.By compressed air jet loading, AN prills were crushed and filled in a bore-hole at high density, 0.85-1.0, to the density of original AN-FO, 0.81.The diameter and the length of loading hose, namely hose resistance, is very much effective on the loading speed of the compressed air loading system of AN-FO. The diameter of borehole is a major affecting factor for the state of AN-FO loaded in a bore-hole such as the density. While, the loading air pressure and the distance between the top of loading hose and the face of charge in a bore-hole are minor factors for the state.Loading techniques of AN-FO by compressed air system is rather experimental and should be established by practical operation in each mine.

著者

山口 梅太郎 下谷 高灑 下村 彌太郎 安藤 行郎

出版者

一般社団法人 資源・素材学会

雑誌

日本鉱業会誌 (ISSN:03694194)

巻号頁・発行日

vol.97, no.1125, pp.1157-1162, 1981-11-25 (Released:2011-07-13)

参考文献数

4

被引用文献数

3 2

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This is the report of the landslide happened on 20th of September, 1973 at the Kagemori limestone quarry, Saitama prefecture. The slide started at about July of 1972 and it took over one year to final slide from the first finding of the crack on the slope. This report includes the record of the displacement of crack opening observed at thecrack on the failure slope and the analitical discussion on the slide.

著者

山口 梅太郎

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.134, no.6, pp.67-73, 2018-06-30 (Released:2018-06-30)

参考文献数

14

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The Chichibu region located in Saitama Prefecture is a limestone mining area. Mt. Buko limestone deposit is located in the Chichibu region and is being collaboratively mined by Chichibu Taiheiyo Cement, Ryoko Lime Industry, and Buko Mining companies by bench-cut from the top of Mt. Buko. Since the start of mining from the top, Mt. Buko has produced about 260 million tonnes of limestone until the end of March 2017 and a large rock slope (over 400 m high, about 2 km wide, and with overall inclination of 45°) has formed. Currently, managing the stability of the rock slope is considered the most important and critical issue at Mt. Buko. The Task Group for Research on Rock Slope in Chichibu Area (Chichibu Zanken) was established before the start of the cooperative mining at Mt. Buko. The Chichibu Zanken is composed of engineers (especially younger engineers) from the three companies and its first meeting was held in November 1973. In the 45 years since then, the Chichibu Zanken has continued to meet and has held a total of 450 meetings. In the beginning, activities of the Chichibu Zanken were more fundamental, focusing on collecting information on slope stability and studying to design a stable rock slope. Since around 1994, monitoring and analysis of slope behaviors have actively intensified. After the typhoon in September 2007, a significant but short-term slope displacement was detected. From analysis of current and previous data, it was found that the rock slope was affected by heavy rainfall. Therefore, slope drainage, pavement to suppress water permeation, steel pipe piling, retailing rock piling on the rock slope, and their effects on slope stability are important discussion subjects for the Chichibu Zanken. Mining of Mt. Buko is ongoing and making the slope to extend further. The Chichibu Zanken is set to play a key role based on accumulated knowledge and cooperation to solve future unforeseen problems.

著者

山口 梅太郎 茂木 源人 山冨 二郎

出版者

東京大学

雑誌

試験研究(B)

巻号頁・発行日

1990

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わが国の石灰石鉱山では、数100mにも達する長大な立坑を利用した露天採掘が行われる。近年になって、ようやく、この立坑内での岩石塊の挙動が解明されるようになってきたが、これらの研究を踏まえて、立坑に投入された鉱石(石灰石)の品位調整を行うことの可能性を得ることを試みた。鉱石は、立坑ヘトラックで運ばれて投入されるので、トラック毎の品位変動が立坑排出口での品位変動にどう影響するかを、立坑現場での実験とこれをモデル化した実験とによって観測し、さらに立坑内での鉱石の挙動のシミュレ-ションによって解析した。その結果1.垂直立坑システムよりも、斜坑システムにおける方が鉱石の混合が促進される。2.斜坑システムの混合特性は鉱石の粒径によって異なる。これは斜坑内において粒度偏析がおきるためと考えられる。3.斜坑システム内の混合特性は、斜坑内での鉱石の降下挙動、とくに不連続性による混合特性と、シュ-トホッパ-部におけるファンネルフロ-に起因する混合特性の合成したものと考えられる。4.斜坑システム内での鉱石の降下挙動は、単純な速度分布を仮定することによってモデル化することができる。5.これによって、鉱石立坑における鉱石の混合特性の推定が可能になった。6.鉱石立坑が使用年月と共に拡大して、容量が変化した場合の混合特性の変化を求めることができた。7.投入鉱石の品位変動が立坑の排出口でどうなるかのシミュレ-ションを行った。等を結論として得ることができた。