All good dude. Blending can take place throughout the supply...

All good dude. Blending can take place throughout the supply chain including the mine, load port, disport and power plant. However receivers would typically not give their consent to adding conventional coking coal to a thermal shipment for concern over VM and swell. Nonetheless, as I said for sake of optimisation it occasionally does happen in small proportions at load port. As long as the main parameters average the contracted spec and the coal performs reasonably well, the power plants typically won't pick it up. Therefore whilst as you say it might be detectable, in practice it usually won't be detected. Since the inflow of coking coal into the thermal market is so restricted thermal coal is currently able to hold its ground and able to attract a better price than met coal despite inferior heat value and ash content.
Btw I have been in the coal industry around the globe in different capacities for most of my working life and can honestly do without your condescending mr. know-it-all comment. Have a great day anyway