Darkness continues to envelop Grand Caverns, America's oldest show cave, after a lightning strike damaged the attraction's electrical system earlier this month, officials there say.

Charmaine Detrow, an education coordinator at the Grottoes park, said caverns officials are still mystified as to how cables and a light box, which provide illumination for tours, were struck by lightning. She said the system is inside the cave with no exposure to the elements.

"There's no doubt in our minds it got hit," she said. "The plastic switches are melted onto the metal box."

Guided tours in the Grand Caverns have been suspended since Aug. 17, the day after the lightning strike occurred, according to park officials.

But the park, which also offers recreational activities like mini-golf, horseback riding, swimming and hiking, is still open.

Detrow said electricians are working to determine the extent of damage before making repairs.

She said park officials hope to reopen on Saturday.

"It really depends on what the electricians find," she said.