The sinking of portions of Mankayan town, in which at least five houses were destroyed, occurred despite warning signs. And many residents point to the decades-old mining in the area as the culprit in the disaster.
By LYN V. RAMO
MANKAYAN, Benguet, the Philippines — Odellon Wallang and two of his children were inside their house along Aurora Street in this town at around 11:45 in the morning of June 5 when they were jolted by a loud crashing sound that he likened to a plane crash.
Wallang rushed to the window to see the whole mountainside going down. “I caught a glimpse of the tail of the mountain sliding down,” he told Nordis.
Immediately, he went out to warn his neighbors but only to find them packing, some already fleeing. Wallang returned to pick up his kids. By then, the trail to the main road of the town was already gone.
“I kicked the fence off, gathered my children and, not long after we left, our house went down,” Wallang said. He was still shaking, his voice quivering as he retold his close encounter with disaster.
Five other houses also collapsed, Wallang said. These belonged the families of Pedro Casaldo, Ben Asiong, Abdon Costian, Salvador Pacsayan and Gloria Ticuala. The last three were grade-school teachers of this town.
Last week’s disaster, which may have been triggered by the nonstop rain here two days before the area practically caved in, was just the latest in similar incidents here that many attribute to mining.
There has been major ground subsidence in the area over the years. The last occurred in 1999, when some 55 houses were pulled down by a landslide. Ticuala, one of the teachers, had actually left the place after the 1999 tragedy but returned here subsequently, only to suffer the same fate again.
A teacher from the Lepanto National High School said a rip-rapped wall at the school had been bulging, indicating a weakening in the wall and warning of an impending collapse. “It was full of mud,” the teacher said.
Pablo Khayog Jr., principal of the Mankayan National High School, had noticed a tree inside the campus changed position. He said he even called the attention of town officials, in a letter he sent them in March.
“They did not bother to investigate. They could have done some mitigating measures,” Khayog told Nordis in an interview Wednesday.
The sinking occurred in the former site of the Mankayan Central School (MCS) to the Mankayan National School (MNHS) athletic oval. MCS is now inside the MNHS campus since it was displaced by a similar disaster in 1999.
The octagon-shaped canteen of the school and a portion of the athletic oval also collapsed, with more cracks evident on the ground just a few meters from the outdoor stage, prompting school and town officials to fence off the subsidence area and organize a 24-hour watch.
“We are closely monitoring the subsidence area. When it rains incessantly, classes would be suspended automatically,” Khayog said.
Not Blaming the Mines
In the absence of an independent investigation, town officials chose to refrain from stating that large-scale mining activities are responsible for the collapse of Aurora.
Residents, however, insisted that the abandoned and sealed underground tunnels may have already collapsed and may have triggered the disastrous ground movement.
NIGS, in its recommendations, mentioned the investigation into the competence of the alleged underground tunnels, which were last investigated in 1974. It also proposed a detailed structural and geologic mapping of the subsidence area, as well as monitoring of the rate of subsidence.
Relocation of residents and business establishments were also then recommended, underscoring consciousness-raising activities about the real threat to life and property.
The Mines and Geosciences Bureau (MGB) of the environment department, in a June 11 report, pointed to fault lines traversing the area of subsidence as evidenced by the nature of landslide materials composed almost wholly of soil and crushed rocks.
The MGB report described the June 5 incident as a major landslide measuring about 44.4 meters wide and some 20 meters deep, which caused the temporary damming of Casibugan Creek below the school site.
Residents, however, said the ground movement was a subsidence, not a landslide. “If it was a landslide, the earth mass could have gone to the other side,” said Wallang, who is also the vice-chairman of the security union of Lepanto Consolidated Mining Company. “The place just collapsed.”