Onlookers survey the damage of a collapsed mine today in India's Godda district. The collapse Thursday has left 10 dead and 23 missing. Rescue efforts were ongoing.

PATNA, India — A coal mine collapse in eastern India killed at least 10 workers and 13 others may be trapped by the mound of fallen earth, police said today.

The collapse happened late Thursday but heavy smog prevented rescue workers from entering the open coal mine until early Friday morning, said S.K. Singh, the general manager of the Rajmahal Open Cast Mines in the eastern Indian state of Jharkhand.

The rescue work was to stop at nightfall.

Jharkhand police spokesman R.K. Malik said 23 workers were reported missing after the accident, and that after 10 bodies were recovered 13 remain unaccounted for.

The Godda district where the mine is located is more than 975 miles southeast of New Delhi.

The coal mine is owned by the state government but is leased to a private contractor. Few other details were immediately available.

Jharkhand is one of India’s poorest states but is rich in mineral resources. It has the third-highest coal deposits of India’s 29 states and the country’s highest deposits of iron ore. Mining and related industries are the state’s economic backbone.