Recent Works

Jiro Yamatomi	University of Tokyo
Hiroshi Shimotori	The Metal Mining Agency of Japan
Susumu Takemura	Engineering Advancement Association of Japan
Yoshio Ohtsuka	Toyoha Mines Co., Ltd.
Osam Sakai	Toyoha Mines Co., Ltd.

Installation of past backfill technologies in a hot and hard rock mine, Toyoha, Japan

The Toyoha Mine is located in the Hokkaido Island of Japan and close to a regional large city, Sapporo, as well as the Jozankei hot spa. Currently, the mine is excavating polymetallic ores by the longhole sublevel stoping from its vein type deposits composed of a large number of veins. The unique features of the deposit are characterized by the occurrence of rare metals such as indium (230 g/t), young geological age of mineralization (3 to 0.5 million years), and high rock temperature partially exceeding 100 degrees Celsius.

In order to improve the underground climate, the mine utilizes the local river water as cooling medium and raise boring machines for construction of ventilation shafts. The mine has a plan to introduce the paste backfilling to save energy consumption and cut operating cost. The paste backfill technology is expected to effectively suppress the heat outflows from the mined out regions and to significantly reduce useless time between mining consecutive sections, which might result in reduction in the total energy consumption. The flow test was initially carried out in 1998 and the second flow test is presently organized and scheduled to be implemented (Figure 4).

Also, you will be able to find the details of the study in

(a) Jiro Yamatomi, et al., Installation of past backfill technologies in a hot and hard rock mine, Toyoha, Japan， (Proc. of Minefill 2001 Symposium, (Seattle), Submitted, 2001).

---