Complex sentence: The land cost about $10,000; much costly machinery was placed in position, and a shaft was sunk feet, There many thousands of tons of copper were taken from the earth, but later all was abandoned and the machinery rusted out with the passing years.
Split into simpler sentences: The land cost about $10,000; much costly machinery was placed in position, and a shaft was sunk there. Many thousands of tons of copper were taken from the earth, but later all was abandoned and the machinery rusted out with the passing years.