Your portfolio is more diversified than mine was when I was your age. I may have been 100% in my company!
It served me well, and my shares went up between 50% and 100% between when I bought them, and a few years later, when I sold them. But I was lucky. If I had waited another five years, they would have been worth between half and a third of what I bought them for. I suspect that you’re in the same boat. Look at the spread in share price, including the 80s and 90s for your particular company, and I expect you’ll see the same thing. The mining industry has a very volatile share price.
I left at the right time (the way it worked was that shares had an interest free 10 year loan, that was paid back with the dividends, so I sold some to keep some). Later (when the share price was really low), the company sold off the section I had worked in. People I had worked with owed more than the shares were worth, and it went really badly for them, because they had to pay back the loan as they were no longer part of the company.
Long story short, I’d sell.