Last checked by Coal Boss
Blending means mixing coals of different quality — usually to reach a GCV, ash or moisture level a customer asks for, or to use up a lower-quality lot alongside a better one.
The expected GCV of a blend is a weighted average by quantity: each coal's GCV multiplied by its tonnes, added together, and divided by the total tonnes. The same arithmetic gives an expected ash or moisture figure — provided every figure is on the same basis.
The arithmetic gives an expectation, not a certificate. How evenly the coals are mixed, how the blend is sampled and how moisture changes all affect the result, so the blend should be sampled and tested before it is sold on a quality specification.
Worked example
Illustration only: 60 t at 4,800 kcal/kg blended with 40 t at 3,800 kcal/kg gives an expected (60×4,800 + 40×3,800) ÷ 100 = 4,400 kcal/kg — if both figures are on the same basis.
Common confusion
Averaging two GCVs reported on different bases (one as received, one air-dried) gives a meaningless number. Convert to the same basis first.
What it means if you trade coal
Work out the expected blend before mixing, then test the blend itself. Sell on the tested figure, not on the arithmetic.
How Coal Boss handles this · In Coal Boss today
Two lots can be blended in the yard; the blended GCV is the quantity-weighted average. Only GCV is averaged, not ash or moisture.
From Coal Boss's verified product record — separate from the explanation above.
Hinglish mein, short mein
Mile hue coal ka andaazit GCV maatra ke hisaab se average hota hai: har coal ka (ton × GCV) jodiye, kul ton se bhaag dijiye — sirf tab jab dono GCV ek hi basis pe hon. Udaharan: 60 ton 4,800 + 40 ton 3,800 → 4,400 kcal/kg. Ye andaaza hai; specification pe bechne se pehle mile hue maal ka test karaiye.
Sources
- ExplanationCoal Boss explanation of common coal-trade practice
- StandardBureau of Indian Standards — IS 1350 (Methods of test for coal and coke)
Coal Boss explanation of common trade practice — not a rule. Every business agrees its own terms.
