A 42-hectare portion the abandoned, heavily-polluted Bagacay Mine in Western Samar has been declared “successfully replanted,” after a six-year project by the Ecosystems Research and Development Bureau (ERDB) and the Mines and Geosciences Bureau (MGB).
The joint project of ERDB and MGB called “An Integrated Science-Based approach in the rehabilitation of mined-out and waste dump areas at Bagacay, Hinabangan, Samar” started in 2009 in the mined-out area of Bagacay, a 2,672 hectare former copper and pyrite area.
Bagacay Mine used to be operated by Marinduque Mine Industrial Corporation from 1956 to 1985 and by the Philippine Pyrite Corporation from 1986 to 1992. It ranked first in the general risk ranking among the seven and inactive mines in the Philippines.
In the joint research project by ERDB and the MGB, both attached agencies of the Department of Environment and Natural Resources (DENR), three experimental blocks of land, all laced with high concentrations of heavy metals and measuring 20 meters by 50 meters each were selected.
“ERDB determined the potential of selected indigenous tree species in regreening and absorbing toxic elements in the abandoned mined-out area,” ERDB information officer Adreana Santos-Remo explained.
Species used in the area were Mt. Agoho (Gymnostoma rumphianum), vetiver (Vetiveria zizanioides), narra (Pterocarpus indicus), Acacia auriculiformis, and mangium (Acacia mangium).
After the study period, high concentrations of heavy metals were recorded for Mt. Agoho, mangium, A. auri, and narra. This showed that the four species planted on the metal-filled soil were most efficient in absorbing the metals and in distributing heavy metals from their roots to leaves.
“Today, the aesthetic condition of the waste dump area has improved. A total of forty two hectares of mined out area have been successfully planted already. The project has also provided employment to the surrounding community,” according to ERDB Director Dr. Henry A. Adornado.
“All hope is not lost for the environment. The initial results of the phytoremediation study conducted by the DENR-ERDB and MGB revealed that mined-out areas can be rehabilitated through the use of appropriate technology,” he added.
ERDB Forester and study project leader Gregorio E. Santos, Jr. said that with the inherent bioremediation (metal and pollutant absorption) capacity of selected tree species along with the fertilization technique, an observable increase in the height of mangium and Agoho del Monte was observed in the former mine.
Biomass (dried leaves and branches) produced by narra was noted to provide nutrients to the soil which prompted the growth of grasses and other shrub species.
The research also revealed that organic fertilizer treatment could work well in areas like the Bagacay mine.
The combination of one by three meter forest soil, 1 liter agricultural lime, and 3 liters of organic fertilizer (chicken manure) was found to be the best treatment for the four tree species that were included in the study, according to ERDB forestry staff Niro Villaceran, Joseph Anthony Luna, Jose Milton Montaras, and Zander Doden.
ERDB hopes that this joint research may inspire other mining companies to use similar rehabilitation protocols to bring back the natural state of the mined out areas in the Philippines.
ERDB is also now implementing the use of other ERDB-developed technologies such as carbonized biomass and Hi Q Vam 1 in this endeavor.
The ERDB experts applied Hi Q Vam on the plants while they were growing.
Hi Q Vam, also known as mycorrhiza, is a fungus that has a symbiotic relationship with plants. Mycorrhiza resides in plant roots and causes soil nutrients to retain in the roots, causing survival and growth in plants despite adverse soil condition such as heavy metal content.
Adornado pointed out that Section 47 of PD 705 of the Revised Forestry Code of the Philippines requires mining companies to restore mined areas as near as possible to their former natural state after mining operations end.
Other rehabilitation projects
Other mine rehabilitation projects that have recently been approved by the DENR include those of Surigao nickel miner Marcventures Mining and Development Corporation (MMDC) and Zambales’ Benguetcorp Nickel Mines, Inc. (BNMI), which is currently suspended from mining operations due to environmental concerns.
Both mines are rehabilitation 50-hectare plots using a soil amendment technology called Activated Biochar, according to information from the DENR.
Biochar is charcoal produced from plant material, which is incorporated into the soil to help remove carbon dioxide from the air, and has some metal-absorbing properties.
MMDC and BNMI are working with the Philippine Biochar Association (PBiA) to develop effective biochar material. PbiA said that its partners, Sambali Beach Farm and Microbial Technology Solutions, have developed specific microbes to be added to the biochar “to activate it for optimum performance in assisting and facilitating plant and life-giving microbial growth in heavily degraded surfaces, such as mined-out areas in Zambales and Surigao.”
In an earlier statement, Marcventures Vice Chairman Isidro Alcantara said his company’s project is not only to comply with requirements of final mine rehabilitation but supports the company’s initiatives to provide sustainable, organic, and environmentally enhancing livelihood activities.
“The idea is to apply Biochar and convert mined-out lands into arable lands which can be planted to renewable cash crops which then gives livelihood that is continuing to the communities especially indigenous peoples,” Alcantara said.