if stripmining is what i think it is, it is not efficent. you have to dig through tons of dirt, stone, and gravel, to even get to ores. you want throughoutness. not eficency. look it up on the wiki!
Strip MIning is efficient. Do you know the meaning of efficient? It's getting the most done in the smallest time. You want 'thoroughness'? Strip mine a 50x50 square out, then mine all the strips out so it's a 50x50 plain strip.