I don't really think it's possible to create a human mineable coin. The problem is you need a PoW algorithm which is hard for bots to solve but easy for humans to solve, but it also needs to be easy for computers to verify the solution. There is no easy way to meet those requirements. The problem space would have to be so huge that a bot wont have any chance at finding a solution by randomly searching for one, but it should be solvable by applying creativity and logic. For example when a programmer is faced with a problem he must apply creativity and logic to write an algorithm which can solve the problem. If he were to randomly try every possible algorithm he would never find a solution, but by applying human reasoning skills he is able to write an algorithm capable of solving the problem. That is the sort of PoW problem required to make a human mineable coin.
what about a captcha type thing? thats easy for humans to solve
The solution cannot be quickly verified by computers unless the solution is already known, but the point of a PoW algorithm is that no one knows the solution until some one finds a solution. The example I gave about the programmer writing an algorithm is a better approach because the solution can be easily verified by a computer, it just needs to run the algorithm and make sure it produces the correct output. The other problem with a captcha approach is that you need a way to decide where the captcha images come from, which requires centralization.