Well, first of all, this is not mining bitcoin, this is a faucet, there is lots of faucets that will give you btc, but most of them will take you ages to get to the minimum withdraw limit. how much do you make on a day on your site?

https://freebitco.in/?r=6261057 is another site that will give you btc, and in this site you can earn btc every hour (win up to 0.03375186 BTC every hour), and play the lottery or gamble them to make more, you will even get over 4% annual interest.