Africans are blessed with a lot of minerals that if this resources are gainfully used for benefit of their citizens, this God given resources would add colours to Africans. Countries in Africans like Nigeria, Serial Leone, Ghana, kenya, south Africa and lots more you will a lot of natural resources either misused or abandon by government and even if they see need to use them, is either abused or mismanaged. Petrol in Nigeria till today is been refined outside country and still import back to Nigeria on a high price, lots of minerals like coals, salt, kerosene, gas, petroleum and so on but no appropriate handling of this resources, so even the citizens can not benefit from it. If Africa can make use of their resources well, they will be more independent, free from indebtedness and indirect colonial system of other countries.
I'm all for the development and prosperity of African countries, but it's not an easy road. First, there's corruption and violence, both of which need to significantly be tuned down for progress. Then there's the impact of colonialism which you've mentioned, and it's unfortunately hard to escape it because economic dependency is still strong. Finally, the world is starting to move away from the exploitation of natural resources toward more sustainable activities because of climate change, so I think that it's not a good time to start working on building economies around minerals and stuff.
I agree with your points specifically the colonialism. Even in the mindset of the people, it is relatively hard to take away from. Perhaps it truly has to do with our dependency on the countries that once colonized us. Even in my country now, despite stating that we are free from colonization from any country it is evident that US have a great grasp on us and our governmental decisions. I'm sure the decisions for our mineral resources (which is rich in our country) is also dependent on what the US and China thinks of it.