Am I using a SEMI-COLON correctly here? (Best Anwser)

Yes.

The sentence structure itself is rather awkward.

The Semicolon doesn't belong there. The first sentence was a complete idea.
Try to shorten and separate your ideas and keep the tone in the 3rd person as opposed to the second.

"Living on Mars will grant the residents many prospects. For example, these residents will have the opportunity to mine for precious metals found on Mars. This lucrative opportunity will be available to them long before many others travel to Mars."

A semicolon is really only ever used prior to an advancement on an idea or within an elaborate list, such as:

"There are three main precious metals found on Mars; aluminum, found in the meteorites; Mercury, found at the basins of the dried oceans; and iridium, found in the rock formations."

Or

"Several fast food restaurants can be found in each of London, England; Paris, France; Dublin, Ireland; and Madrid, Spain."

It's basically either when you're making a list of items in which commas are not appropriate for use because the list ideas have commas within them.

If it's not being used for a list, the ideas must be very closely related to each other.

"A man chooses; a slave obeys."
"I like to eat cows; however, I don't like to be eaten by them."