Simplify the following text for a Grade 6 native English-speaking person.
Original: The township was established a few years later and subsequent gold mining , predominantly driven by the Port Phillip and Colonial Mining Company saw the town 's population rising to well over 6,000 residents in the late 1880s .
Simplified: The town began a few years later . With the opening of a big gold mine , by the Port Phillip and Colonial Mining Company , the town 's population grew to over 6,000 people in the late 1880s .