20 Runecrafting and 36 Mining

Today I got my RCing up to level 20 and Mining to 36. A few days earlier, I got the random event where you had to get 3 questions right in a test. My reward was the Book of Knowledge, with which I chose the RCing level.

I'm planning to make some money by iron mining for a month. These are my calculations:

Each 20min session = 84 ores
Each weekend = 168 - 242 ores
Each month = 672 - 968 ores
Each ore sold at 100gp = 67.2k - 96.8k a month
= 806.4k - almost 1.2m a year