VISIT TO KELIAN GOLD MINE (CLOSED) IN INDONESIA

Kelian Gold Mine was  once operated by Rio Tinto Limited and continues to manage the rehabilitation program of the mine Tailings Dam  after the mine closed back in 2005. The mine is located in East Kalimantan, Indonesia on the island of Borneo. 

Kelian Mine commenced production in 1992 and ceased production  in 2005. It is a closed mine which still monitor some of its closed domain such as : 

- Namuk Tailings Dam

- Waste Rock Dump

- Hydro Dam

- Kelian River Diversion Area

- Kelian Mine Pit Lake

 - Wetland Areas

- Ohter Rio Tinto Foundation Facilities.

Kelian Mine Pit Lake

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Application of Geotextile on Slope Stability for Establishment of Tailings Dam in Gold Mines – The Case of Hidden Valley Mine, Papua New Guinea

1. Introduction

The Hidden Valley (HV) tailings dam/storage facility (TSF – Fig.1) is constructed with downstream method of embankment. The initial dam crest elevation was designed for RL 2,000 with a storage capacity of 40Mt of tailings with a mill throughput of 4.2Mtpa, (Rynhoud et al., 2017). The TSF has reached its designed capacity at RL 2,000 and the mining company plans to raise the dam height to RL 2,015 to increase the volume. In this study, it proposes for further 20m dam height expansion in two stages (RL 2,025 & RL 2,035) with the application of geotextile reinforcements for slope stabilization.

Fig.1 Hidden Valley (HV) tailings dam

2.Numerical Simulation

Analysis of the TSF is carried out in 2 cross sections (Fig.2) with 4 stages (stg): RL 2,000(stg.1), RL 2,015(stg.2), RL 2,025(stg.3), RL 2,035(stg.4). Phase2 software is used for numerical simulations with: (1) no reinforcement; (2) geotextile reinforcement. Desired critical shear strength reduction factor (SRF) is 1.3 and above.

Fig.2 Model view of section AA' and BB' at RL 2,000

3. Results, Discussion and Conclusion

Fig.3 Stability of dam at different RL with no support

Fig.4 Stability of dam with reinforcements at different RL in X2

Fig.5 Effectiveness of reinforcements at RL 2,000 (X1)

It is unstable at initial stage with no support in X1(Fig.3). Geogrid and Geocomposites are unstable in X1, whereas structural interface is stable in X1(Fig.5). In X2, it is stable at initial stage, but unstable as the dam height increases (Fig.3). Geogrid and Geocomposites are stable at initial stage but, unstable as dam height increases (Fig.4). Structural interface is consistent and stable (Fig.4).

RL 2,035 is possible to achieve with the application of geotextile reinforcement in structural interface for stability in both X1 and X2.

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Small Scale Mining in Papua New Guinea

The Alluvial Mining Sector in Papua New Guinea (P.N.G.) contribute significantly to the country's economy. The gold produced by small scale miners eventually get to the gold exporters that in return bring in foreign currency into the country.

However, Mine Waste Management is an issue for almost all the miners in the country.

The mining operations contributes to the sedimentation that causes high turbidity of  rivers and streams where alluvial mining happens.

Luckily, most of the small scale mining operations use gravitational method and gold recovery where gold is physically separated from the gangue materials. Thus, least chemical is used. 

Below is a typical alluvial mining operation in PNG

 

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