I understand your problem. If one would be interested in investing in the junior mining sector, the question arises where to start.
There are several hundreds of junior miners listed in Canada alone, then there's AIM, JSE, ASX...
So I decided to go for a similar approach that I used in my previous job when looking for potential acquisition targets. You sum up a number of factors that you'd like to rate the companies on. You may have a preference for small caps or large caps. Then you may have a preference for producers or explorers.
Like I said, sum up those factors in an excel file and then make a short list based on the most important factors. Geopolitical risk may be one factor to stay away from. That would eliminate pretty much all junior miners in South America or Russia.
Factors I've applied are market cap, reserves (ind./inf. & type of metal), geopolitics, share price (must be below C$0.20, although this is in fact a ridiculous factor for a short list but you have to start somewhere :-)), cash position and management experience.
That brought me to a short list of some thirty of fourty companies out of which I bought into 20-25%. Do your own DD and put some time into it..! Good luck!