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.
if with mining you mean cloudmining then never even try to think about to invest in those sites..
peoples are still saying some cloudmining sites are trusted and actually paying but I don't think they will remain trusted long..[
For doubling bitcoin best website is coince.com they gives 180% in 60 days and I had got full payment for 2 sessions but i can guarantee when they will run away (as no mining site 100% trusted) still i suggest you invest there because you could earn some extra till the company last
Coince.com is already declared a scam it is not paying anymore. and all hype sites are scam. and investing 500$(coince's mnimium investment) to a scam site is totally an idiotic thing.
when was the last time you got payment from Coince.com BTW?