Generally, coking coal is above 14, which is reserved in the contract.
If you want to improve the Y value, you must add fat coal or main coke clean coal, which will inevitably cause changes in G and V ... If the change is not big, it will not affect the price.
General coking coal: y>16g & gt85a <; 10.5V & lt; 28
Fat coal: Y & gt20 & gt90a <; 10.5V & gt; 28
1/3 coking coal: y>14g & gt75a & lt10.528 < V & lt37
thank you