Last checked by Coal Boss
Proximate analysis is the routine lab test for coal. It reports moisture, ash, volatile matter and fixed carbon as percentages. In India the methods are set out in the Bureau of Indian Standards' IS 1350.
Ash is what is left after the coal burns — the non-combustible part. More ash means less useful heat and more residue for the user to handle.
Moisture is water in the coal. Total moisture includes surface water from rain, washing or storage; inherent moisture is held within the coal itself. Because moisture adds weight but no heat, the same load reported 'as received' and 'air-dried' can show quite different ash and GCV figures.
What it means if you trade coal
Ask which basis every figure is on before you compare two reports. A wet monsoon load can weigh more and test lower on GCV than the same coal in dry weather — both at the weighbridge and at the lab.
Hinglish mein, short mein
Coal ka aam lab test — proximate analysis (IS 1350) — moisture, ash, volatile matter aur fixed carbon batata hai. Ash jalne ke baad bachta hai; moisture paani hai jo wazan badhata hai par garmi nahi deta. Isliye 'as received' aur 'air-dried' ke figure alag aate hain — do report hamesha ek hi basis pe milaiye.
Sources
Coal Boss explanation, based on the sources above.
