Tailings cease to flow at Marcopper mine

The tailings leak at Placer Dome’s (TSE) Marcopper mine on Marinduque Island in the Philippines has stopped, and the operators of the mine are preparing to install a temporary seal.

Tailings began leaking March 24 from a mined-out open pit being used as an impoundment; the concrete plug in the pit-floor tunnel failed, allowing the water-saturated tailings to escape into the nearby Boac River. The leak stopped on its own on March 28, likely because fine-grained tailings began to clog the breach.

Local and international consultants are designing a replacement seal while Marcopper (39.9% of which is owned by Placer Dome) pumps water from the tailings pond to decrease pressure on the plug. The spill is benign, according to Marcopper and the Philippine Department of the Environment and Natural Resources, both of which have been monitoring the river since the spill.

The discharge, however, increased the level of the river and cut off access to some villages after crossings were washed out. Marcopper has been constructing levees to prevent flooding of agricultural land.

A report carried by the Bloomberg news agency quoted Victor Ramos, the cabinet minister responsible for the environment portfolio, as saying Marcopper would be denied approvals for any future developments.

The Philippine Trade Commission in Toronto confirms that the governor of Marinduque province, where the mine is situated, had petitioned the national legislature for that measure. Ramos later withdrew his statement in a conversation with Marcopper’s vice-president, Ted Gabor.