Core Box Size Guide: BQ, NQ, HQ, PQ and Sonic
The short answer
Match the box to the core diameter: BQ core (1-5/8 in) goes in a BQ box, NQ (2-1/8 in) in an NQ box, HQ (2-5/8 in) in an HQ box, PQ (3-3/8 in) in a PQ box, and 4 in sonic core in a sonic box. A standard five-row BQ, NQ or HQ box holds 10 feet of core. PQ and sonic boxes hold 5 or 6 feet because the core is thicker and the rows are wider. To size an order, divide the planned hole depth in feet by the feet per box, then add a few boxes for broken ground and the partial box at the end of every hole.
Which core size is which
| Core size | Core diameter | Typical use |
|---|---|---|
| BQ | 1-5/8 in (36.5 mm) | Shallow or tight-budget exploration, underground |
| NQ | 2-1/8 in (47.6 mm) | The most common exploration size |
| HQ | 2-5/8 in (63.5 mm) | Resource definition, better recovery in broken ground |
| PQ | 3-3/8 in (85 mm) | Large-diameter, metallurgical or geotechnical samples |
| Sonic | 4 in | Sonic drilling, overburden and unconsolidated material |
Box capacity and dimensions
All CGS wax cardboard and plastic corrugated boxes share the same footprint per size.
| Box | Rows | Holds | Outside dimensions (L x W x H) |
|---|---|---|---|
| BQ | 5 | 10 ft | 25.5 x 9.25 x 2.5 in |
| NQ | 5 | 10 ft | 26 x 12.5 x 2.5 in |
| HQ | 5 | 10 ft | 26.75 x 16 x 3 in |
| PQ, 2 row | 2 | 5 ft | 32.25 x 8.25 x 4 in |
| PQ, 3 row | 3 | 6 ft | 26.5 x 11.5 x 4 in |
| Sonic | 2 | 5 ft | 31.5 x 10.5 x 4.5 in |
How many boxes does a hole need
Feet per box: 10 for BQ, NQ and HQ. 5 for PQ two-row and sonic. 6 for PQ three-row. The table gives the exact count; order a few more than the math says, because broken core, rubble intervals and the partial box at the end of every hole use more room.
| Hole depth | BQ, NQ or HQ boxes | PQ 2-row or sonic | PQ 3-row |
|---|---|---|---|
| 200 ft | 20 | 40 | 34 |
| 500 ft | 50 | 100 | 84 |
| 1,000 ft | 100 | 200 | 167 |
| 1,500 ft | 150 | 300 | 250 |
| 300 m (984 ft) | 99 | 197 | 164 |
| 500 m (1,640 ft) | 164 | 328 | 274 |
Wax cardboard, plastic corrugated, heavy-duty plastic or Discoverer tray
| Wax-impregnated cardboard | Plastic corrugated | Heavy-duty plastic | Discoverer Series 2 tray | |
|---|---|---|---|---|
| Ships | Flat, bundles of 10 | Flat, bundles of 10 | Assembled, each | Nested when empty, each |
| Assembly | Fold, no tools | Fold, no staples or glue | None | None |
| Water | Wax resists moisture | Water and most chemicals cannot penetrate | Resists moisture, chemicals and extreme temperatures | Drainage holes, UV-stabilized polypropylene |
| Lid | No | No | Removable lid included | Lid sold separately |
| Stacking | Yes, with bands | Yes, with bands | Stackable | Stacks full, nests empty, core never touches the tray above |
| Sizes | BQ, NQ, HQ, PQ 2 and 3 row | BQ, NQ, HQ, PQ 2 and 3 row, sonic | NQ, HQ | HQ, PQ |
When to pick which. Wax cardboard for a short program, a dry climate, or core that goes to the lab and the box is disposable. It is the lowest cost per foot. Plastic corrugated when the core will sit outside, get rained on, or be handled for more than one season. Same footprint as cardboard, still ships flat. Heavy-duty plastic when the core is archived long term or trucked a lot. The lid is the point. Discoverer trays when freight matters: empty trays nest, which cuts shipping volume, and the color coding sorts sizes at a glance.
Blocks, markers and bands
Every box needs interval markers and something to hold it shut. CGS wood core blocks fit NQ and HQ boxes and come in bags of 50. Discoverer plastic core blocks fit NQ, HQ and PQ, have an etched top for a permanent marker, and come in bags of 50. Discoverer Series 2 core markers come in packs of 100 for NQ and HQ and packs of 50 for PQ. Red rubber bands for NQ and HQ boxes come in bags of 50; UV-resistant bands are available for boxes that will sit in the sun. Plan on two bands per box.
Frequently asked questions
What size core box do I need for HQ core?
An HQ box. It is 26.75 x 16 x 3 in, five rows, and holds 10 feet of 2-5/8 in core.
How many core boxes do I need for a 1,000 foot NQ hole?
100 boxes hold it exactly. Order a few more to cover broken ground and the last partial box.
Are wax cardboard core boxes waterproof?
Wax-impregnated cardboard resists moisture and handles normal field wetting. For core that will sit in rain or snow for a season, use plastic corrugated or heavy-duty plastic.
Do core boxes come assembled?
Cardboard and plastic corrugated boxes ship flat and fold up on site without tools, staples or glue. Heavy-duty plastic boxes and Discoverer trays arrive ready to use.
Can I stack core boxes on a pallet?
Yes. Use rubber bands or lids to keep them closed, and strap the pallet. Discoverer trays have strapping slots built in. A pallet cover keeps the stack dry.
What is the difference between a core box and a core tray?
Same job, different construction. A core box is a folded cardboard or corrugated plastic container. A core tray is a molded plastic unit, usually with drainage holes and a separate lid, built to be reused across programs.
How fast do core boxes ship?
In-stock orders placed by 2:30 pm Pacific, Monday to Friday, ship the same day from Sparks, Nevada.
Written by the CGS Mule team, Sparks, Nevada. Updated October 2026.