The previous statement was in regards to the extraction of value - modern markets are such that the best(/fastest/easiest/etc) way to make money is to be at the top of the value chain and let your capital do the work. This is a self-reinforcing feedback loop, enabling you to use your increasing gains to find other forms of leverage (in your example - buying the mine and the equipment, setting up commodity trading positions, etc) and keep on ratcheting up the leverage. One inevitable outcome is for you to have the opportunity to use this leverage against the people doing the actual digging up of the gold.
If value was derived from capital itself, then a pile of tools or machines would spontaneously generate wealth without the application of human labor, and idle money in a bank would somehow enrich society.
you are only counting the human labour involved in the creation of value.
what about the capital?
Would you, as a hired gold miner, be able to accept zero pay for your work, until the gold is sold (then you got the full price of the sold gold)? What if you starved between the time you mined it, and the time it takes to sell? And how would you have gotten the equipment to do the mining in the first place, let alone the ownership of the mine.