Complex sentence: On October 13,1941, a geological survey of Smooth Island was conducted to determine the possibility of mining phosphate on the island, concluding that phosphate mining on Smooth Island was unlikely to be viable.
Split into simpler sentences: On October 13,1941, a geological survey of Smooth Island was conducted to determine the possibility of mining phosphate on the island. The conclusion of the study was that phosphate mining on Smooth Island was unlikely to be viable.