Checked, oil has been discovered in Niger in the 70's...so yeah... And they are still poor?!
And even then, they should have exchanged a package: Exploitation rights against revenue with costs of infra + maintenance deducted.
There needs to be roads or trains assuredly and whatnot for those exports to transit.
Who cares if they get a better bargain from the US, the Chinese or whoever else. That's competition. That's supply and demand. That's how they should get the most of what they have. No need to be so sour about it.