A drill program lives or dies on whether the core in the boxes is still legible five years from now. Good core sample storage and organization comes down to five things: marking blocks at every interval (not just every box), depth in feet AND metres on every block, climate stability where the boxes live long-term, a logging system that ties the box to GPS coordinates and a drillhole ID, and stack geometry that doesn't crush the bottom rows. Most programs do the first three reasonably well and lose 30% of legibility on the last two. This guide walks through what we've watched work — and not work — over 90 years of shipping core boxes into Canadian exploration programs.
The five essentials of a working core library
We don't log core ourselves — but our boxes have lived in every kind of core shack from a heated indoor library in Saskatoon to a tarp-covered yard in northern Quebec, and we hear back about which setups stay legible and which don't. The five things that consistently separate working libraries from broken ones:
- Marking blocks at every interval. Not just box ends — between every row inside the box. Depth in both feet and metres, pencil-marked on raw wood.
- Labels that can survive the storage environment. Pencil on raw wood, embossed metal tags, or laser-engraved blocks. Marker on plywood fades in two seasons of UV.
- Shelter from precipitation and sun. Temperature stability matters less than dry, shaded conditions.
- A digital log tied to physical boxes by barcode, QR, or sample number. The box knows where it lives; the database knows what's in it.
- Stack geometry that won't crush the bottom row. Maximum five high for HQ framed, four for PQ. Racking for anything taller.
Labelling — the part everyone underestimates
Drill core boxes can sit in a yard for 20 years. The label has to make it that far. Most labels don't. Marker fades, paper labels delaminate, printed stickers peel off in freeze-thaw, painted-on text chalks in UV.
What we've seen survive long-term:
| Method | Lifespan outdoors | Cost | Notes |
|---|---|---|---|
| Pencil on raw spruce | 20+ years | Free | Counter-intuitive but proven |
| Embossed aluminum tag | 30+ years | Medium | Resistant to weather and fire |
| Laser-engraved marking block | Indefinite | Medium-high | Best for high-value programs |
| Marker on plywood | 1-2 years | Free | Fades fast in UV |
| Printed label sticker | <1 year outdoor | Low | Acceptable only indoors |
Marking blocks — the highest-leverage habit
A marking block is a small piece of wood (we mill them as a stock product) sized to fit between rows of core in a box. It carries the depth at that point in the box and any notes — end-of-run, recovery percentage, change in lithology.
Crews that mark every interval, not just every box end, save their future selves enormous time. A geologist coming back to re-log a section can find the exact depth they need without counting cores. An assay tech pulling sample intervals can confirm they're in the right run without going back to the database.
We stock precision-milled marking blocks sized to our standard core box widths. Order them with the boxes.
Climate and shelter — what actually matters
You don't need a heated, climate-controlled core library to keep core legible for 20 years. You need shelter from rain, shade from direct sun, and reasonably stable conditions. A unheated metal-sided shed in northern Manitoba does the job as well as a heated facility costing 10x — provided the roof doesn't leak and the floor stays off bare ground.
What kills legibility is cyclical wetting. Boxes that get rained on through a torn tarp, dry out in the summer, get snowed on in the winter, and thaw back to wet in spring will lose labels and check apart within a few years regardless of construction.
Stack geometry and rack design
Loaded HQ core boxes weigh 60-65 lb. Five high is fine in our 2x6" framed construction. Six high starts to bow the bottom row. PQ at 90 lb loaded should top out at four high.
For long-term libraries, build a steel-tube or 4x4-post rack with cross-bars every two rows. The load transfers to the rack, not the box below. We've seen rack-stored boxes survive 30+ years with no structural compromise.
Chain of custody — the digital layer
The physical organization is half the system. The other half is a digital log that says where each box lives. Best practice:
- Unique sample number or barcode on each box, tied to a drillhole ID
- GPS coordinates of the drill collar (in case the program name or property name changes ownership)
- Box location within the library — rack, row, slot
- Photo of the loaded box, taken at logging time, stored with the database record
Even a spreadsheet with these columns is enough. The point is that a person 10 years from now can find the box from the drillhole ID and the database, not by memory or shop folklore.
Stocking up for your program
If you're setting up a new core library or replacing worn-out boxes from a previous program, we ship core boxes, marking blocks, and lids across Canada from Cranberry Portage. Tell us your bit size, your meterage, and your stacking plan and we'll quote a bundle that fits. Reach us at our contact page.
Frequently asked questions
How should drill core boxes be labelled?
Every box needs three pieces of permanent labelling: drillhole ID, depth from-to (in both feet and metres), and box number out of total (e.g. 7/24). The labelling goes on the end of the box where it's visible when boxes are stacked, plus a second copy on the inside of the lid. Marking blocks inside the box mark depth intervals between every row, not just every box. Pencil on raw wood lasts longer than marker on plywood — counter-intuitive but true after a few seasons of UV.
What is the right temperature and humidity for storing drill core?
Stable matters more than specific values. Core kept in an unheated outdoor shed at -30C to +25C is fine if the humidity tracks with that temperature naturally. What kills legibility is cyclical wetting and drying — boxes that get rained on, dry out, then get rained on again, lose labels and check apart in the wood. Aim for shelter from precipitation and direct sun. Insulation is nice but not required.
How high can you stack core boxes safely?
Five high for loaded HQ core boxes is the common ceiling in framed 2x6" construction. Beyond that the bottom row carries 300+ lb and will start to bow. For PQ (heavier) drop to four high. For plywood construction reduce by one row across the board. If you need taller stacks, build racking with crossbars every two rows so the load transfers to the rack instead of the box below.
What information needs to live with each core box?
At minimum: drillhole ID, depth from-to, box number/total, date drilled, logger initials, project name. Best practice adds GPS coordinates of the collar (so the box can be re-located in a coordinate system if the project name changes hands), and a unique sample barcode or QR code that links to the digital log. The marking block at each row stores depth + run length so a viewer doesn't have to do mental math to find an interval.
How long should drill core be retained?
Regulatory minimums vary by province (Manitoba mineral exploration: 10 years from end of program in many cases — check current regs before assuming). In practice, the cores from any property that's still being optioned, drilled, or modelled should be kept indefinitely. The replacement cost of re-drilling a hole to recover a sample you tossed runs into five figures fast.
What is the most common core organization mistake?
Skipping marking blocks between rows. Crews label the box ends well, then leave the inside of the box without depth markers between rows. Six months later a geologist trying to find the 247-251m interval has to count rows from the start of the box and assume even run lengths — which they almost never are. Marking blocks at every row, with depth printed in both ft and m, is the single highest-leverage habit.
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