CORYDON, Ind. (AP) _ Rescuers chiseled away rock inside a cave today and freed a cave explorer who fell 30 feet in a pit and was badly injured.

Kenny Carrigan of Indianapolis was injured Sunday afternoon at Birthday Plunge Cave about 25 miles west of Louisville, Ky. He was finally freed this morning, 18 hours after the accident, and was being taken to University Hospital, Humana, in Louisville.

Rescue crews worked through the night, first raising him from the bottom of a pit and then chipping away rock so that Carrigan could be lifted from the cave entrance.

''It's hard going. It's very hard going,'' Tom Sawtelle, assistant manager of the Wyandotte Woods recreation area, said prior to the rescue. The recreation area is part of Harrison Crawford State Forest.

Carrigan had a deep cut on his head and also an injured, possibly broken, pelvis, Sawtelle said. During the night, he received intravenous liquids and was kept warm with blankets and heating pads.

Carrigan, described as an experienced cave explorer who had taken part in rescuing other people, was with two other spelunkers when he slipped from a ledge about 100 feet deep inside the cave to another ledge 30 feet lower.