Ask an owner what he paid for coal this month and he will tell you to the rupee. Ask him what coal cost him per thousand bricks and the answer is usually a shrug, or a figure remembered from a good month two years ago.
That gap matters. Coal is, on most kilns, the single largest cost after labour, and it is the one cost that changes with how the fire is run. A careless fireman, a wet week, a line loaded too tight: each shows up as more coal for the same bricks. If you cannot see the number, you cannot see the problem.
Why the monthly total hides the truth
The monthly coal bill mixes everything together: coal bought but still in the yard, coal used on lines that are not yet unloaded, coal used on lines unloaded last month. Dividing the bill by the bricks sold this month gives a number, but not a useful one.
The useful number is per round, per line: how much coal went into this line, and how many good bricks came out of it.
What to record
Three entries, all of which happen anyway:
- Each firing shift: which line, how many kilograms of coal, who was firing. Two shifts a day, so two entries.
- Loading: how many green bricks went into the line.
- Unloading (nikasi): how many bricks came out, by grade: awwal, doem, khangar.
With these three, the arithmetic is simple. Add up the coal on all the firing entries for that line’s round. Divide by the bricks unloaded, in thousands.
A worked example, with made-up numbers
Say a line was loaded with 24,000 green bricks. Over its firing shifts the entries total 14,400 kg of coal. At unloading, 23,000 bricks come out in sellable grades. The illustrative figures: 14,400 ÷ 23 = about 626 kg of coal per thousand bricks. At a coal price of, say, Rs 40 per kg, that is roughly Rs 25,000 per thousand bricks in coal alone. These are example figures, not benchmarks; your own kiln, coal quality and season will give different ones. The point is the method, not the number.
What the number tells you once you have it
- Line against line. If line 9 used a quarter more coal than line 8 for the same bricks, something happened on line 9: loading, weather, the fireman on duty. Now you can ask.
- Month against month. Coal per thousand tends to rise in cold and damp weather. Seeing the curve lets you plan purchases instead of reacting.
- Fireman against fireman. Not to punish, but to learn. The fireman with the lowest coal per thousand and good awwal percentage knows something worth passing on.
- Pricing. When a buyer argues over the price of awwal, you know what one thousand actually cost to make.
Keeping the record honest
The weak point is the coal weight. If coal is shovelled by the basket and estimated, the number will drift. Weigh what you can, estimate consistently when you cannot, and record the estimate as an estimate. Equally, record coal purchases and keep a running stock; when the stock goes negative in the book, a firing entry or a purchase is missing, and the app’s health check will say so.
A bhatta that knows its coal per thousand is a bhatta that can tell a good month from a lucky one.