Good news is that, your reserve will hardly last for 70 years and when it runs out you wont be out of business. Planet has more time to develop an alternative!
Bad news is that your stock prices went steeply down as the supply of the commodity is going to steadily increase. Over exploitation is a sure fact! Over exploitation of the resource which would ensure that by the time your reserve runs out the new one would too.
The government has planned to send the resource extraction team which includes massive infrastructure and dozens of ships to the island. This could possibly take a month or two.
Here is the question. You have time until the government team can make it to the island. You must ensure that the resources is kept untouched for some couple of decades, you cannot move it or steal it. All your plans for protecting the resource from getting exploited must be completed within the next few weeks and you cannot go back to the island for at least a few decades! Not even a single life should be shed, bribery? No!
Clue: The way out is a bit complicated. So think hard and think flexible!
If you found out the way to regain your market share and keep your share prices on fire mail me at tijosdesk@gmail.com. Let the adventure begin!