Take a look at the following gold companies that I really like. Gold is easier to deal with the poor logistics of Africa than the base metals which require shipping large volumes of ore.
http://www.westafricanresources.com
https://www.cardinalresources.com.au
The pictures on Tietto's website really show what mining is like in a lot of Africa without western capital.
Tickers for others to save a bit of time:
ASX:RSG ASX:WAF ASX:CDV ASX:TIE
WAF and CDV are both listed on the TSX (Canada) as well.
If you are interested in learning about Australian mining companies then take a look at Hot Copper. Watch out as like most stock internet message boards there is a lot of ramping, but there is also a huge amount of useful information there too. Just make sure to check everything you read yourself.