Rock & Mining Drill Bits

India is the world's second-largest coal producer, and the scale of its mining ambition is written into the ground. Coal India Ltd (CIL) and Singareni Collieries (SCCL) operate some of the planet's largest open-pit blast-hole fleets across the coalfields of Jharia, Korba, Talcher and Singrauli, where benches are advanced day and night to feed thermal power and steel. Each of those benches starts with a drill bit, and the choice of bit decides cost-per-tonne as surely as the explosive that follows.

Open-pit production drilling typically calls for 152–311 mm blast-holes on 10–25 m benches. In the soft overburden and coal seams, air-flush tricone bits are the standard rotary tool: dry benches favour air flushing, which clears cuttings without water and keeps holes clean for charging. Where the rock turns to hard Deccan basalt or granitic iron-ore, the economics often shift toward DTH button bits running down-the-hole hammers — a method that delivers straight, fast small-diameter holes in abrasive crystalline ground.

Iron-ore drives a second front. The hematite belts of Odisha, Jharkhand, Chhattisgarh and Karnataka — including the Bellary-Hospet sector — present hard, abrasive ore that punishes gauge and bearings. Here the grade of tungsten carbide buttons matters enormously: insert geometries and carbide grades are chosen to balance impact toughness against abrasion resistance, so a bit survives the percussive load without rounding off its gauge row prematurely.

Matching method to formation is the core skill. Our comparison of DTH and tricone drilling explains when a hammer beats a rotary bit and when it does not, while the operating engineer's view of insert selection lives in our blast-hole carbide guide. The short version: tungsten-carbide insert grades are selected for impact in fractured, blocky rock and for abrasion in hard, competent rock — the wrong grade fails fast either way.

VBM India supplies the Volgaburmash mining range from stock in Dubai, with the lead time to India confirmed with every quote. Whether you run rotary air-flush tricone bits on blast holes, pilot bits for raise boring or FDC bits on exploration holes, the team can spec the right tool for your formation and quote availability and lead time.

By mine type

• Open-cast coal (Coal India subsidiaries, Singareni): overburden of sandstone and shale; air-flush TCI tricone bits of IADC series 4–5 in 250–311 mm (9 7/8"–12 1/4") on rotary blast-hole rigs.
• Iron ore (Odisha, Jharkhand, Chhattisgarh, Karnataka): banded hematite quartzite and jasper are very hard and abrasive; TCI series 6–7 with gauge protection, e.g. AIRX 637Y or 727Y with a sealed journal bearing.
• Limestone for cement (Rajasthan, Madhya Pradesh, Andhra Pradesh): series 5–6 in 6 3/4"–7 7/8" (171–200 mm); smaller holes are usually drilled with DTH button bits.
• Granite and aggregates: series 7 with conical inserts for tough, abrasive rock.

Rotary tricone vs button bits

“Rock drill bit” covers two families: rotary tricone bits for blast holes of about 6 3/4" and larger, and button bits for top-hammer and DTH drilling in smaller holes. Rotary tricones drill faster and cheaper per metre in large holes and softer overburden; DTH button bits win in very hard rock at smaller diameters. Both rely on tungsten carbide buttons — see our carbide mining buttons guide.

AIRJ, AIRP or AIRX

All three lines are for rotary blast-hole drilling with air or air-water flushing, and the last digit of the IADC code shows the bearing: AIRJ codes end in 2 — open roller bearing; AIRP codes end in 5 — sealed roller bearing with gauge protection; AIRX codes end in 7 — sealed journal bearing with gauge protection. AIRJ covers 6 3/4"–16" (171.4–406.4 mm), AIRP and AIRX 7 7/8"–12 1/4" (200.0–311.1 mm). Decode any code with the IADC tricone bit code chart.

What is a rock drill bit?

The cutting tool at the end of the drill string that breaks rock to make a hole. In mining it is either a rotary tricone bit for blast holes or a button bit for top-hammer and DTH drilling.

Which rock drill bit sizes are most common in Indian mines?

Rotary blast holes in coal and iron ore are usually 9 7/8"–12 1/4" (250–311 mm); limestone and aggregate quarries use 6 3/4"–7 7/8" (171–200 mm), with DTH button bits below that.

Do you have mining drill bits in stock?

Yes — air-flush tricone bits from the AIRJ, AIRP and AIRX series, mostly 7 7/8"–12 1/4", plus DTH RC bits. We ship from our Dubai warehouse by air or sea; the exact lead time is confirmed in each quotation.

Are you a rock drill bit manufacturer?

VBM India is the authorized distributor of Volgaburmash (Samara, Russia), the largest manufacturer in Russia of rock cutting tools, whose history traces to the Kuybyshev machine building plant established in 1948. We supply factory bits with datasheets.