14 December 2024
Seeing firsthand how nickel mining operated by Harita Nickel in Obi Island, South Halmahera, North Maluku, gives us pride. It is because nickel ore, which is one of Indonesia's rich natural resources, is directly mined and processed in its site to produce ferronickel as well as Nickel Sulfate and Cobalt Sulfate. Whereas in the past it was exported abroad in the form of nickel ore, so Indonesia used to be criticized for selling its land and water literally.
On Obi Island that is not the case. Nickel ore in the form of saprolite is processed into ferronickel, while limonite which has a low nickel content is processed into nickel sulfate and cobalt sulfate with High Pressure Acid Leaching (HPAL) technology.
After the nickel mining was completed, the ex-mining areas were properly reclaimed as evidenced by the normal growth of vegetation. As a soil science background person, I am well aware that it is not easy to grow revegetation plants in topsoil dominated by iron oxide. This kind of soil has a high pH around neutral. That seems good, but despite the high pH, these soils have a very low net positive charge and Cation Exchange Capacity (CEC), so their ability to absorb nutrients in the form of cations is also very low.
In addition, the amount of Ca-exchangeable in this soil is smaller than the amount of Mg-exchangeable, so plants will experience Ca deficiency, an element that is essential for plant cell development. The cropping conditions in the Harita Nickel reclamation area show that these soil properties can be overcome by applying high doses of compost, which is more than 20 tons/ha.
However, even though it is good, for future revegetation programs it is strongly recommended that the compost used be improved first by adding FABA ((Fly Ash and Bottom Ash, which is waste ash from burning coal in Steam Power Plants) with a ratio of compost: FABA 75: 25 or KomFABA 75: 25.
Compost is very good for improving soil physical properties and increasing soil CEC. However, compost has low nutrient levels and requires a long time to be available to plants, which is through the decomposition process. Therefore, adding FABA can ensure the availability of nutrients needed by plants in a short time because FABA contains various nutrients in soluble form. The addition of FABA to compost will also reduce Ca deficiency in plants.
KomFABA can also be utilized in Salam Kawasi Agropark. Various food crops such as tomatoes, eggplants, corn, chilies, and others can be planted in this area as a pilot as well as to prove that the food produced in this area is safe for consumption, of course, after being proven by laboratory analysis.
In addition to good plant growth conditions in the reclamation area, Harita Nickel's seriousness in carrying out reclamation is also evident in the provision of various kinds of seeds with quantities exceeding the needs of revegetation each year. These seeds are prepared in a modernly built nursery area. Harita Nickel's concern for the environment is also evident in keeping erosion and sedimentation under control by building extensive settling ponds TG 1 and TG 2. These settling ponds are proven to keep the beach and sea around Obi Island, which is directly opposite the mining area, clean and blue. Also the presence of 2 very large coal domes can maintain air quality to be free from flying coal dust pollution.
Harita Nickel also cares about its surrounding community by building the Kawasi Baru area for the settlement of indigenous people of Kawasi Village. Community empowerment is also carried out for rice farmers, planters, fishermen, and entrepreneurs of tofu, tempeh, processed nutmeg, banana chips, and others.
We would like to thank Harita Nickel for the opportunity to visit Obi Island. We gained a lot of experience and knowledge, which we will certainly pass on to our students at our beloved IPB campus. From Obi to Campus, to Indonesia and to the World.
*This article originally written by Prof. Dr. Ir. Iskandar, Department of Soil Science and Land Resources, Bogor Agricultural University (IPB).
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