No— Just worthless rock but how much of your grandkids money do you want to spend on that mine? I can get all the silicon you want down at my beach house.
Dr Gerald O'Neill who formulated these plans as a Physics Professor at Princeton along with Werhner von Braun knew that the space program could be self funding and provide a profit to boot.
The return on investment, (ROI) for the average company is 10 to 15%. The ROI on the Apollo Program is closer to 700%. Own a computer? Owne a satelite TV receiver? Own a cell phone? Own a GPS receiver? All came from Apollo era inventions and created millions of jobs and incresed our GDP significantly.
Go Into Space? You Betcha!!!!!!