<span>The United States would oversee the continuance of the Open Door policy.</span>
Large companies took over the mining because Congress passed laws granting underground mining rights to certain companies.
Explanation:
US was in the middle of a gold and oil rush as a lot of resources were discovered on the US sol by industrialist who moved into the towns and built big industries around the mines and mined the resources.
This became a hegemony of big companies because the Congress passed laws to grant the underground mining rights to certain companies only.
This made the business a hegemonic one.
