Surplus Value is the amount that is stolen by the Bourgeoisie from the workers’ labor power that does not tie into their means of subsistence. What you described was simple commodity hording until the Irpn Ingot was worth 12 units of a universal commodity known as cash. Yet someone lost that 12 wads of cash to recieve something worth 12 wads of cash, it’s zero-sum exchange baby. Anyways, just check this post for M-C-M' cycle: https://steemit.com/steemit/@theironfelix/the-pervert-s-guide-to-m-c-m