How many tries does it usually take to get a bandos chestplate in runescape?

I want to be a member and I have 87 mining so i can mine rune and earn about 220k an hour. I really want full bandos (chesplate and tassy). I was wondering how many times do you have to kill general graardor to get a drop. How many tries did it take you. And should i just mine rune and earn the money or fight graardor. which way would be faster?