Sustainable Business in Post-Mining Land: A New Paradigm

The land area of 8 million hectares (80,000 km2) is a large area, even the area is roughly equivalent to twice the size of the Netherlands or Switzerland or as large as Austria. Various types of plants can be planted or cultivated on the land, both food crops, energy (bioenergy), feed and biomaterials. This is very much in line with the current era of bioeconomics and decarbonization where world attention is focused on reducing carbon (CO2) emissions from fossil fuels to non-carbon in an environmentally friendly and sustainable way. And moreover Indonesia's location is on the equator so it has a tropical climate so it is very suitable for plant cultivation or biomass production for the purposes as above. The 8 million hectares of land is unproductive land or more precisely damaged land, namely post-mining land in Indonesia. Restoring (recovering) the land to a minimum condition like pre-mining is the responsibility of the mining companies. Of course it would be even better if the recovery was better than pre-mining conditions considering that a number of mining businesses generate large profits so environmental improvement efforts such as reclamation and post-mining rehabilitation should be carried out easily.

In addition to residential areas, tourism, water sources and cultivation areas, revegetation is one of the efforts for reclamation and rehabilitation of post-mining land (OP phase reclamation program attachment VI Kepmen ESDM No. 1827 K/MEM/2018). Revegetation for the ultimate goal of an environmentally friendly, sustainable and profitable business activity is certainly the best solution. The general characteristic of ex-mining land is a thin layer of top soil and subsoil so that little soil organic matter and soil microbes are needed for plant growth. It is impossible to simply revegetate land with these extreme conditions, therefore successful revegetation of ex-mining land can only be achieved by combining soil amendments, species selection and application of appropriate silvicultural techniques. This is because these business activities provide environmental, social and financial benefits. Revegetation with productive plantations or forests is an effort to achieve this. How big the benefits are, of course, needs to be studied in more depth on the types of productive plantations or forests that will be created.

The type of mine also influences the post-mining reclamation and rehabilitation work. In almost all coal mines there is no further processing, in contrast to mineral mines which require further processing. In post-mining reclamation coal mines it is simpler just to return the soil to its original condition whereas in mineral mines, apart from returning the soil as in coal mines, the problem of tailings (waste soil left over from the mining ore extraction process) is also another problem, whereas in smelters or smelters (processing/refining) of these minerals also produces slag (post-operation) which can also be another additional problem. The damaged lands in the post-mining reclamation area need to be repaired or rehabilitated so that they can return to their previous condition. The addition of organic fertilizer and biochar, will accelerate the improvement of soil fertility. Acceleration of soil fertility is important to accelerate the growth of plants planted in the area so as to reduce the potential for natural disasters such as floods and landslides. The use of biochar can also provide valuable additional income from carbon credit through a carbon sequestration / carbon sink mechanism. 

In these land conditions, not all types of plants or trees can be planted on the land. Trees or plants that can live and grow in marginal and even extreme conditions are the choices for these land conditions. Energy plantation of legumes (fast growing species) and bamboo is the best choice for the land. In energy plantations from legumes (fast growing species), apart from having high adaptability to marginal conditions including minimal water availability, the root nodules are also useful for fertilizing the soil. Wood from energy plantations is used for bioenergy into products such as wood pellets, while the leaves are for animal feed and honey from beekeeping which utilizes the flowers of these plants. Bamboo plants also have high adaptability. Products from bamboo plantations can be in the form of food, namely from bamboo shoots and the bamboo itself for various purposes. Industrialization of bamboo so that it becomes high added value products must be carried out. Almost all wood products can be replaced with bamboo and even the quality can be better, such as furniture, bamboo boards, ply bamboo and so on. With the existence of a sustainable industry that takes advantage of the products from the post-mining reclamation land, a number of benefits as mentioned above will be obtained.

The potential of 8 million hectares of land will produce very large biomass products if managed properly and correctly. The era of electric vehicles which is also expected to soon become a world trend will also require electrical energy stored in the battery. The electrical energy used should also come from renewable energy, not from fossil energy sources. The energy source from biomass to electricity is an ideal renewable energy source for the electric vehicle energy source. Production of biochar by pyrolysis and production of biogas from livestock manure as organic matter can be used for electricity production. With a number of driving forces and future trends, it is important to consider the utilization of the 8 million hectare land.