Chocolate drop is a mine feature where miners hit a weakness in the rock creating this collapse and the geologic feature we see today. 

The void has a rusty sulfur type smell and seems to have a lot of corrosion on the walls which appears to have created this weakness. 

There were multiple passages that continued but without proper equipment and gas meters we did not continue the exploration. 

 We used rope to access the void and found this to be more of a mining feature with some geologic significance than anything cave related. 

If you are interested in this kind of exploration, make sure you reach out to qualified organizations or local caving grottos for more information.