Mexico says mine did not report huge acid spill, allowing pollutants to flow into river

A civil defense official says a private mine in northern Mexico did not report a massive acid spill, allowing it to flow into a river that supplies water to tens of thousands of people.

The official says the spill at the copper mine in northern border state of Sonora state was caused by defects in newly constructed leaching ponds.

Sonora state civil defense director Carlos Arias says last week's spill of about 10 million gallons (40,000 cubic meters) of mining acids was detected by residents downstream.

Arias says tests have revealed the spill contains pollutants like arsenic above acceptable levels. Water supplies from the river have been cut off to about 20,000 people.

The Grupo Mexico company operates the mine, but did not respond to requests for comment on Tuesday.