Fair and honest advice I am sure. Just a few notes.
Firstly with an established resource of 300+ million tons of resource (concentrate 70%) and a likely resource of 1billion ton and a proposed production of 10million ton per annum with plenty of potential to increase and/or upgrade (peletization) production this is hardly a "small" project.
Also it is not "green" but it is actually green. Even if production were to be done conventionally and the IO were to end up in a regular blast oven the higher grade will mesn much less CO2 produced. It will always be a win for the environment.
Further NPV stands for Net Present Value. Or with other words if we assume the project to be completed based on numbers as we currently have them and then discount that with a applied cost of money (usually 8 or 10%) for the time till production, this is what it should be worth today. Therefore if those numbers hold up the actual market cap once in production should actually be higher then the current NPV. This applies to all mining projects. It's obviously very important to do your own research to be able to understand if the numbers used are reasonable.
Mate you have done very well by making 40% in 2 days. It pretty obvious (and understandable given your experiences) that you are not 100% convinced nor comfortable leaving all your money in HIO.
It might be wise to sell up or significantly decrease your holding so you feel more comfortable. I do suggest you do a bit of digging into this company and then you can always decide to buy back in or increase. I think the more you read up the more you will like it. I think the posters here provide great information but obviously they are biased and you should absolutely balance that with your own insights. But that might take more then 2 days.
HIO Price at posting:
10.5¢ Sentiment: Buy Disclosure: Held
(20min delay)