BOGOTA, Colombia (AP) – A makeshift gold mine collapsed in southwest Colombia on Saturday, killing 21 people and injuring another 18, authorities said.

Efforts were under way to find about 10 miners missing and presumed trapped underground in the mine, located near the town of Suarez, 220 miles southwest of the capital, Bogota.

“There are still a lot of people to rescue, and we don’t know what conditions they’re in,” a policeman who identified himself as patrolman Delgado said by telephone from the mine. “Initially they said there were around 50 people trapped.”

Officials had recovered 21 bodies and rescued 18 people who were hurt in the morning collapse, said Delgado, who declined to give his name because he was not an official police spokesman.

“Initially they said there were around 50 people trapped,” he said.

Local residents began excavating in the mine after it was reported that gold had been found deep underground. Rescue efforts have been hampered by the lack of any registry or count of how many people entered the mine system.

Rich in resources, but a limited government presence across a lot of the country, makeshift mines are a common sight across much of Colombia, in particular those zones where gold or emeralds have been found.

With little to no oversight, mining accidents are a frequent occurrence in this Andean country.

In February of this year, an explosion in a mine killed 32 miners. The same month another accident killed 8 more miners.