Drill core tray handling: protecting sample integrity from rig to core shed

A drill program’s whole value is locked in the core it recovers. Mishandle the trays between the rig and the core shed and you degrade the one physical record you can’t re-create without spending the budget twice. The tray is not packaging — it is the carrier of order, orientation and depth, and choosing the right one protects every decision built on the core for years afterward.

Why does drill core handling matter so much?

Because drill core is a permanent, re-loggable record of what’s underground, and unlike an assay number you can’t regenerate it without re-drilling the hole. Geologists return to archived core years later to re-log, re-sample and validate a deposit, so a tray that spills, mixes or loses its depth markers compromises the record and every interpretation downstream of it.

This is not a fringe concern. Australia’s national and state geoscience agencies maintain dedicated core libraries precisely because the physical sample outlives the rig that pulled it — Geoscience Australia holds national drill-core and sample collections as a long-term scientific asset for the country (Geoscience Australia, ga.gov.au). When the archive is the asset, the container that protects it is part of the asset too. A cracked timber tray or a column that topples in the core farm doesn’t just cost a tray — it can cost the integrity of metres of irreplaceable core.

What does a good core tray actually do?

A good core tray does four jobs at once: it holds the core in sequence and orientation, survives the field, stacks and locks square, and stores for years without degrading. Get any one of those wrong and the tray becomes the weak link in an otherwise expensive, carefully run program.

• Holds order and orientation. Moulded compartments keep runs in sequence and the right way up, with room for depth blocks and labels that survive handling. Once a run is logged out of order, the depth record is compromised.
• Survives the field. UV, heat, dust and rough loading on corrugated tracks are the norm, not the exception. Trays need to take it without cracking, warping or going brittle.
• Stacks and locks. Trays that stack square and stable cut spills during transfers and store tightly in the core farm. A tray that bows under load makes the whole column unstable.
• Stores for years. The library is a long-term archive, so the tray has to outlast the program that filled it — sometimes by a decade or more.

Where does core get damaged — rig to library?

Core gets damaged at the transfers, not on the rig. The path runs rig → ute or truck → logging bench → core library, and every handover is a chance to drop, mix or mislabel a run. The more manual transfers between recovery and archive, the more points of failure — so the design goal is to cut handling steps and keep the tray stable through every one that remains.

Trays that nest empty for the trip out to the rig and stack securely once loaded for the trip back reduce both the handling time and the number of things that can go wrong. A loaded tray that locks to the one below it won’t walk on a bouncing tray deck; a tray that holds its depth blocks won’t lose the boundary between two runs when it’s tipped onto a logging bench. The handling chain is also a work-health-and-safety chain: lifting loaded trays repeatedly across a long logging day is a hazardous manual task under the model WHS framework, and Safe Work Australia’s code on hazardous manual tasks treats repetitive lifting and awkward handling as risks to be designed out, not pushed onto people (Safe Work Australia, safeworkaustralia.gov.au). A lighter tray that handles cleanly is both a sample-integrity decision and a safety decision.

How many metres of core fit in a tray?

The honest answer is “it depends on your core diameter and tray profile,” but you can plan it. The table below works from the standard diamond-drilling core sizes — NQ, HQ and PQ — to show how diameter drives the metres of core you fit per tray, the trays you generate per 100 m of hole, and the core-farm footprint that follows. These are planning estimates to size your tray order and storage area, not a substitute for your own tray’s published capacity; the core diameters are industry-standard, the per-tray figures assume a typical multi-row tray holding roughly 4.5 m of core.

Two lessons fall out of the table. First, diameter, not depth, is what loads up your tray — a metre of PQ core is more than three times the mass of a metre of NQ, so a PQ tray reaches a sensible manual-lift weight far sooner. Second, the tray count is large and predictable: a single 100 m hole generates roughly 22 trays, so a modest program can run into the thousands of trays that then have to be stored, racked and found again for years. Both facts point the same way — standardise on one or two tray profiles, size the lift to your heaviest core, and plan the core-farm footprint before the first hole is collared.

Why choose plastic core trays over timber?

Plastic wins on every property that decides sample integrity over a long program. Timber is cheap up front, but it absorbs moisture, swells, warps and splinters, and the labelling fades or peels — which is exactly the failure you can’t afford in an archive meant to last a decade. Across a full program the durable container is the cheaper one, because it isn’t the thing that fails.

• Won’t rot, warp or splinter in wet core sheds or after years stored outdoors — the moulded shape it ships with is the shape it keeps.
• Lighter to lift than a saturated timber tray, which is a real WHS difference over a long logging day and across thousands of lifts.
• Consistent moulded compartments for clean, repeatable storage and racking — every tray indexes the same way.
• UV-stabilised grades for remote sites shrug off sustained Pilbara or Goldfields sun where timber and lesser plastics go brittle.
• Reusable across programs instead of one-trip timber that’s thrown out at the end of each campaign.

The same logic that pushes mine sites off timber pallets applies to trays: hygiene, water resistance, weight and lifespan. We unpack that comparison in depth for pallets in plastic versus timber for export, and the trade-offs carry straight across to core trays and site bins.

How should I store and rack core for the long term?

Store loaded trays so the bottom of every column or rack bay isn’t over-loaded and the load is spread, not concentrated. A core farm holding thousands of trays is a storage-engineering problem as much as a geology one: free-standing stacks must stay low enough to stay square on a level base, and dense, deep archives are safer in steel racking where beams carry the weight across a defined span.

This is where core trays meet pallet-racking physics. The trays sit on pallets, and a pallet on a beam rack carries its load unsupported across the span — which is why its racking rating is far lower than its static (floor) rating. The international pallet test method, ISO 8611, sets out how static, dynamic and rack loads are measured and caps how far a deck may deflect, and Australian racking is governed by AS 4084; both treat the unsupported span as the limiting case (ISO 8611, iso.org). Size the pallet under your core trays to its racking figure, not its headline static number — we walk through that distinction in plastic pallet load ratings: static vs dynamic vs racking.

A flat-top, full-perimeter heavy-duty pallet like the one above is the right base under a stacked column of loaded core trays in the farm: the perimeter base spreads the load, the anti-slip top keeps the bottom tray from walking, and the 2,000 kg racking rating gives real headroom for a dense column on a beam. Standardise the pallet and the tray together and the whole archive racks, scans and retrieves the same way every time. Browse the rest of the rackable options in the plastic pallet range.

What about bulk, coarse-reject and sample handling?

Core is only part of a drill program’s material. Coarse rejects, bulk metallurgical samples, RC chip bags and ore-sample lots all need rigid, stackable containers that survive a remote site and store tightly — and the same durability case for trays applies to the bins those samples live in. Where a tray protects the logged core, a rigid bulk container protects the bulk material you keep for met testwork or future re-assay.

The handling math here mirrors the tray decision. Bulk sample material is dense, so the container hits its weight limit on volume long before it runs out of strength, and it gets moved by forklift across uneven pads rather than carried — which makes the dynamic (forks-moving) rating and a square, stable stack the figures that matter. A rigid one-piece body also keeps fines contained and sample lots separated, so there’s no cross-contamination between a coarse reject and the next lot, and no timber fibre or rust shedding into material you may re-assay years later. Standardising the footprint of your sample bins to the same 1165 mm or 1200 mm family as your core-tray pallets means one rack layout, one forklift-tine setting and one storage plan across the whole pad.

A one-piece HDPE pallet box like this one suits coarse-reject storage and bulk sample lots: 1,400 litres of capacity, a 7,000 kg static rating for dense material, and a moulded body with no timber to rot or steel to rust on a wet pad. For reagent drums, fuel and chemical handling on the same sites, rigid containment and spill control sit alongside sample storage — see mine-site spill containment and the full IBC and bulk container range. Everything we supply into resources sits under one roof in the mining and resources range.

How do I brief a supplier on core trays?

Give a supplier three numbers and the rest of the spec falls into place: your core diameter, the run length you want per tray, and your core-farm stack or rack height. Those decide the tray profile, the lift weight, and the pallet and racking it sits on — and they’re the difference between a tray order that racks cleanly for a decade and one that fights you from the first hole.

• Core size. NQ, HQ, PQ or a mix — this sets compartment width and the metres-per-tray you can plan around.
• Run length per tray. Balances trays-per-hole against a sensible manual-lift weight for your heaviest core.
• Storage method. Free-standing stacks or beam racking — this sets the pallet’s racking rating and the stack height you can safely run.
• Site conditions. Outdoor, remote, high-UV core farm versus a covered shed — this sets whether you need a UV-stabilised grade.
• Program scale. Total planned metres — this sizes the tray order and the core-farm footprint before you collar a hole.

Tell us your program and we’ll match trays, pallets and site bins to it — use the guided product finder to shortlist by load and application, or send your core size, metres and freight postcode for a spec-backed quote. Need a tray or bin size that isn’t standard? We manufacture, import and source to spec.

Common questions

What size drill core tray do I need?

Match the tray to your core diameter and the run length you want per tray. Common diamond-drilling sizes are NQ (47.6 mm core), HQ (63.5 mm) and PQ (85 mm); a larger diameter means fewer metres per tray and more trays per hole. Most programs standardise on one or two tray profiles so trays stack, rack and store consistently across the whole project.

Why are plastic core trays better than timber?

Plastic won’t rot, warp, swell or splinter in a wet core shed or after years outdoors, it’s lighter to lift over a long logging day, and its moulded compartments hold core in clean, repeatable order. Timber trays absorb moisture, lose their labelling and degrade, which puts the long-term integrity of an archive at risk.

Can plastic core trays be stored outside in the Pilbara or remote sites?

Yes — UV-stabilised plastic is built for sustained sun, heat and dust, which is why it suits remote core farms where shade is scarce. Specify a UV-stabilised grade for any tray that will live outdoors, and stack on a level base so the bottom trays in a column aren’t carrying an uneven load.

How high can I safely stack loaded core trays?

It depends on the tray’s stacking strength and whether you stack free-standing or in racking. Free-standing columns should stay low enough that the bottom tray isn’t over-loaded and the column stays square on its base. For dense, deep archives, steel racking with the load spread across beams is safer than tall free-standing stacks — the same unsupported-span logic applies as for plastic pallets.

How do I keep core oriented and labelled through handling?

Use trays with moulded compartments that hold each run in sequence and the right way up, leave room for depth blocks between runs, and label in a way that survives UV, water and abrasion. The fewer manual transfers between the rig and the library, the fewer chances there are to mix runs or lose a marker — so trays that nest out and stack back cut both handling time and error.

Sources: Geoscience Australia (national drill-core and sample collections). Safe Work Australia, Model Code of Practice: Hazardous Manual Tasks (repetitive lifting and awkward handling as risks to be controlled). ISO 8611 (Pallets for materials handling — Flat pallets; static, dynamic and rack test methods and deflection limits) and AS 4084 (steel storage racking) for the storage-and-racking guidance. Core diameters (NQ 47.6 mm, HQ 63.5 mm, PQ 85 mm) are standard diamond-drilling sizes; the metres-per-tray, mass and tray-count figures are planning estimates and vary with your tray profile, core recovery and program design. Capacity and load figures for named products are the manufacturer’s tested ratings and vary with load distribution and storage method. Site requirements vary by program and ground conditions; treat this as general guidance, not a rack design or a quote.