Journal of MMIJ
Online ISSN : 1884-0450
Print ISSN : 1881-6118
ISSN-L : 1881-6118
133 巻, 8 号
  • 小林 幹男
    2017 年 133 巻 8 号 p. 193-206
    発行日: 2017/08/25
    公開日: 2017/08/26
    ジャーナル オープンアクセス

    Recently the treatment of mine drainage, especially acid mine drainage (AMD) is attracting a lot of attention, including the passive treatment that is a cost-effective and energy efficient process. In such a process, the natural geochemical reaction, gravitational flow, bacteria metabolism, etc, are utilized for the active treatment, enabling continuous addition of chemical reagents and maintenance of mechanical facilities, and so on. For a long time, the development of the passive treatment was mainly carried out in North America and Europa, thus, much useful knowledge is cultivated and many experimental and actual sites are operated in these area. In this paper, the useful knowledge, information and instances related to the passive treatment are reviewed. The performance of sulfate reducing bacteria (SRB) is very important for the treatment of the mine drainage from non-ferrous mine sites. Thus, the matters related with SRB, that is, the reaction, the reactor and the operation are also described in detail.

  • 佐々木 順悠, 村上 進亮
    2017 年 133 巻 8 号 p. 207-213
    発行日: 2017/08/01
    公開日: 2017/08/31
    ジャーナル オープンアクセス

    Mineral prices hit their ceilings and started fluctuating. It forced resource-related companies to reassess their assets. In order to secure the stable supply of resources, it is important for Japan, which is a resource-importing country, to keep an eye on the changes in strategies of resource-related companies, especially mining giants that dominate the global production of various minerals. There are some studies focusing only on risk management at an individual mine level and fluctuation in mineral prices, but few studies focus on asset management of the mining giants as an entity. The purpose of this paper is to analyze and understand the asset management strategies of the mining giants. All assets of the giants, such as mines, smelters and refineries are considered as risky assets, calculating the optimal portfolio under the Modern Portfolio Theory. By comparing the derived optimal portfolio with the actual one, we conclude that the mining giants' asset management strategies are almost optimal. We also found out which asset will be on sale from each company, which can be useful for Japanese companies increasing the share in overseas mines.