Complex sentence: Afterwards, he acquired control of several of Nicaragua's gold mines, which had been destroyed during raids by Sandino's forces, unsuccesfuly attempting to restore mining operations for the La Luz company, until they sold their holdings to the Nevada-based Tonopah Mining Company.
Split into simpler sentences: Afterwards, he acquired control of several of Nicaragua's gold mines, which had been destroyed during raids by Sandino's forces. He unsuccesfuly tried to restore mining operations for the La Luz company, until they sold their holdings to the Nevada-based Tonopah Mining Company.