I do not like to invest again in mining sites because i have a bad experience before that i got scammed and i do not like to happen to me again that is why for boosting my income in bitcoin i choose to invest in trading it is very convenient and easy to earn bitcoin.
Yes i dont know good where to invest but i can tell you to not do it in mining sites because these will run away with your money eventually and scam you so maybe you can invest in gambling sites instead but anyways you have to be really careful
so instead of mining sites , why don't you try to invest on trading ? maybe it still risky but you wouldn't have a loss actually because the money you have invested were not literally lost if ever there was a fall of price or should i say the price of a certain coin goes down but i don't think that it will happen immediately if you have some good analysis to the coin .
I think trading has less risk in compare to mining site as in mining once you invest you don't have any control on your money, and you will depend on them for returns, but in trading you can take actions according to your wish.