Seeking Possibilities in Environmental Reclamation of the Post Tin Mining Site in Indonesia

Seeking Possibilities in Environmental Reclamation of the Post Tin Mining Site in Indonesia

The Center for Southeast Asian Studies (CSEAS), Kyoto University
ITO, Masayuki Environmental Remediation Group

Figure 1 Belitung Island and deserted mines

Tin has been mined on the Bangka Belitung Islands in Indonesia since the 18th century. Although the scale of mining has shrunk today, it is still ongoing. After tin is mined; scarred regions of sand and clay sediments are left, and can be observed as vegetationless wastelands (Figure 1). The purpose of this project is to revitalize the wastelands. We are conducting onsite soil surveys and vegetation restoration surveys so the landscape can be afforested and its biomass be used as natural resources.

Figure 2 Survey of ecological environment of trees

As the price of tin falls and its production drops, peppercorn cultivation is increasing in its place. Gliricidia, trees belonging to the legume family, are used as splints. We sought to restore stripped lands with this tree, and explored with local community members its possibility of supplying biomass. We also conducted groundwater surveys to ascertain water supplies necessary for the growth of plants, and examined the relationship between the water supply and the growth of Gliricidia in each survey site. Furthermore, we carried out pot experiments to obtain detailed knowledge about relationships between soil samples and nutrients (Figure 2). To understand geographical information of the surrounding land, we obtained spatial information using a drone (Figure 3) and extracted minute topological information. We thus understood bit by bit the relationship between Gliricidia growth and environmental conditions.

Gliricidia trees has high survivability despite harsh growth conditions due to droughts in Belitung. Based on this finding of the tree’s characteristics, we learned that Gliricidia is a species with high potential for use in afforestation. We believe it is possible to establish methods for restoring land stripped by human activities by conducting further surveys and clarifying environmental conditions for growing Gliricidia.

Figure 3 Obtaining geospatial information with a drone