Core Box Sizes: Which Box for NQ, HQ, PQ and SQ Core?

The right core box depends on one number: the diameter of your core. Most diamond drilling programs use the wireline Q series, so in practice you choose between NQ, HQ, PQ and SQ boxes. This page shows the sizes side by side and which of our boxes fits each one.

Geologists logging rock in the field

Core and hole diameters of the Q series

SizeCore diameterHole diameter
BQ36.4 mm60.0 mm
NQ47.6 mm75.7 mm
HQ63.5 mm96.0 mm
PQ85.0 mm122.6 mm
SQ101.0 mm134.0 mm

Holes are often telescoped: drillers start in PQ through broken ground near surface, reduce to HQ and finish in NQ at depth. That means one hole can fill boxes of three sizes, so it pays to order all of them before the rig arrives.

Matching core boxes

SizePlasticWoodGalvanised steel
NQ (47.6 mm)DD-AP-5-48-K, 5 coresDD-GB-6-47-H, 5 coresDD-GB-6-47-S, 6 cores
HQ (63.5 mm)DD-AP-4-64-K, 4 coresDD-GB-4-63-H, 4 coresDD-GB-5-64-S, 5 cores
PQ (85 mm)DD-AT-3-86-K, 3 coresDD-GB-3-85-H, 3 coresDD-GB-3-86-S, 3 cores / DD-GB-4-86-S, 4 cores
SQ (101 mm)DD-AP-2-115-K, 2 coresWooden SQ box, 2 coreson request

All boxes take 1 m core lengths. Details per size: NQ core boxes, HQ core boxes, PQ core boxes. Larger cores, up to 180 mm, are made to order as custom wooden boxes.

How many boxes do I need?

Divide the planned metres by the number of cores per box. A 300 m HQ hole with 4 cores per box needs 75 boxes; add a margin for broken intervals, depth blocks and re-boxing; around 10 % is a common planning allowance. If the hole is telescoped, split the metres by size first.

Core box calculator
Boxes needed–

Estimate: drilling metres divided by cores per box, plus an allowance for broken intervals and re-boxing.

See the full range of plastic core boxes and wooden core boxes, or send us your drilling plan and we’ll work out the quantities with you.