Study predicts black sand mining could sink areas in Northern Luzon
The online news portal of TV5
BAGUIO CITY, Philippines -- A study by US scientists predicts that areas in Northern Luzon mined for magnetite, or black sand, could sink and be underwater within 30 to 70 years, prompting an environmental group to call for a stop to the extractive industry to prevent what it said would be a “massive” disaster.
“Sites with subsidence rates of 1.8 and 3 cm/ a year are projected to be underwater in 50-70 years (while those with) subsidence rates of 4.3 and 4.6 cm/ year are projected to be underwater in 30- 40 years,” geologist Estelle Chaussard of the State University of New York and political scientist Sarah Kerosky of the University of California said in their article, “Characterization of Black Sand Mining Activities and their Environmental Impacts in the Philippines Using Remote Sensing.”
The two aimed “to monitor, control and respond to black sand mining activities and their environmental and societal impacts.”
Remote Sensing is a method of analyzing data from remote satellite images to “sense” a change in the geophysical maps of target areas. It uses the Interferometric Synthetic Aperture Radar or InSAR, which has been successful in detecting ground deformations linked to geohazards such as earthquakes, volcanic eruptions and land subsidence due to groundwater extraction, to assess which communities with black sand mining activities are most vulnerable to sea level rise and impacts of climate change.
The study targeted 20 black sand mining sites from the 28 in Cagayan and 18 in Ilocos Sur, most of these illegal, and recruited the local groups Defend Ilocos and Federation of Environmental Advocates in Cagayan, both convenors of the Amianan Salakniban (AS or Defend the North) network to assist.
Based on the results, Chaussard and Kerosky identified areas that saw “critical” land subsidence from 2007 to 2013: Lingayen (4.8 cm/yr), San Marcelino (1.3 cm/yr), Candon City (3.0 cm/yr), Santa Lucia (4.3 cm/yr), Dagupan (4.3 cm/yr), Santa Maria (2.5 cm/yr), Masinloc (1.8 cm/yr), and Balanga (2.6 cm/yr).
"We know the negative effects of black sand mining as experienced by the communities based only on observation, but seeing proof based on a high tech scientific study with our own eyes should really bother us even more and challenges us to act to change this alarming future,” AS spokesman Fernando Mangili said.
“Rapid subsidence results in high exposure to flooding and seasonal typhoons, and amplifies the effect of climate change-driven sea level rise,” Chaussard and Kerosky said in their article.
“We show that several coastal areas will be at sea level elevation in a few decades due to the rapid subsidence. Since subsidence likely continues to affect the areas even decades after the cessation of mining activities due to the disruption of the sediment budget, characterization of the temporal evolution of land subsidence with longer SAR temporal coverage will be critical to mitigate environmental and societal effects of black sand mining activities,” they added.
Mangili urged the national and local governments to act immediately to prevent what he said would be an environmental catastrophe that could rival the magnitude of 2013’s super typhoon Yolanda in Eastern Visayas.
“Let us protect the future of our people in the coastal areas by stopping large-scale magnetite mining in the Philippines," he said as he called on the Mines and Geosciences Board to do its job.
“A lot of times, illegal mining activities continue even though the communities report it to authorities. This is true in the case of illegal Chinese mining in Cordon, Isabela that up until now, the MGB hasn’t stopped it despite the community’s protests. People in Cordon, Isabela still report that illegal mining is very much alive in the area," he said.