Choosing the right core box might look like a procurement detail, but for any drilling program it is a decision that affects sample integrity, transport efficiency, long-term storage, and the final exploration budget. The same diamond core can arrive at the warehouse intact, fragmented, or contaminated depending on the material it travels in. Below we compare the four most common options on the market — plastic, wooden, metal, and cardboard — across the three dimensions that matter to mining and exploration teams: physical performance, operations and logistics, and cost and sustainability.
How to Compare Core Boxes
A core box is never just a container. It is the first piece of infrastructure that protects a meter of drilled rock as it moves between the drill site, the logging shed, the laboratory, and the long-term storage facility — sometimes for the entire life of a project. Three criteria families drive that performance:
Physical performance: how the box behaves under impact, weather, UV exposure, corrosion, insects or rot, and aggressive chemicals.
Operations and logistics: weight, stackability, nesting for storage, magnetic neutrality (important for sites running magnetic surveys), and handling safety.
Cost and sustainability: upfront price, service life, recyclability, and recycled content.
The four materials available on the market deliver very different combinations of these properties.
Metal Core Boxes
Metal trays are the heavyweight option, literally and figuratively. They offer high impact resistance, good insect and rot resistance, and long service life, which makes them appealing on paper for projects that expect rough handling.
The tradeoffs are significant. Metal corrodes in humid, saline, or acidic environments — a serious limitation for tropical, coastal, or sulfide-rich settings. UV protection is only partial, chemical inertness is poor, and the boxes are not lightweight, which inflates freight cost on every haul.
They are also magnetic, which interferes with magnetic susceptibility readings and downhole surveys. Sharp edges can pose a handling safety risk during long logging shifts. The upfront cost is high, and although the material is recyclable, it is rarely made with recycled content.
Metal makes sense in very specific scenarios where impact loads dominate and the chemical environment is benign — but for the average diamond drilling program, the operational drawbacks outweigh the durability advantage.
Wooden Core Boxes
Wood has been the default in many exploration regions for decades, mostly out of habit and local availability. Wooden boxes offer medium impact resistance, medium service life, and are non-magnetic, which is useful for magnetic testing workflows.
Beyond that, the limitations stack up quickly. Wood has no extreme weather resistance, no UV protection, only partial corrosion resistance, and no resistance to insects or rot — a critical weakness in humid climates where termites and fungi can destroy a stored archive in a few seasons.
Chemical inertness is partial at best. Wooden boxes do not nest for storage, so they consume valuable warehouse space when empty, and they are not lightweight, which raises transport costs. Upfront cost is medium, recyclability is partial, and they are typically made from virgin material.
Wood is acceptable for short-term campaigns in dry climates with minimal storage horizons. For multi-year programs or any tropical environment, it tends to become a recurring replacement expense.
Cardboard Core Boxes
Cardboard sits at the low end of the market: low impact resistance, no extreme weather resistance, no corrosion or rot resistance, and low service life. It is lightweight, fully recyclable, often available with recycled content, and non-magnetic, which makes it attractive for short, indoor handling.
In practice, cardboard is only viable as a temporary or single-use solution. The moment the boxes need to survive a rainy haul road, a humid warehouse, or a few months of stacked storage, the material fails.
Plastic Core Boxes
Engineered plastic core boxes — the kind manufactured by Coreplast — were designed specifically to address the failures of the other three materials. The performance profile reflects that:
- Physical performance: high impact resistance, full extreme weather resistance, corrosion resistance, insect and rot resistance, UV protection, and chemical inertness across the typical reagents used in geology and laboratory work.
- Operations and logistics: lightweight construction, high stackability, true nesting for empty-box storage, fully non-magnetic, and safe handling edges that protect logging and sampling crews.
- Cost and sustainability: competitive upfront cost relative to metal, long service life, 100% recyclability, and production using recycled material.
Engineered plastic is also dimensionally stable, which means lid alignment, partition spacing, and labeling positions stay consistent box after box — a property that matters when thousands of trays are catalogued in a single project database.
The practical implication is that plastic core trays carry sample integrity from the rig through to long-term archival storage without the failure modes that affect metal, wood, or cardboard at different points in the workflow.
A Practical Side-by-Side
| Criterion | Metal | Cardboard | Wood | Plastic |
| Physical performance | Mixed | Low | Low–medium | High |
| Operations and logistics | Low–medium | Medium | Low | High |
| Cost over the project lifetime | High | Low upfront, high turnover | Medium with replacements | Competitive with long service life |
| Sustainability | Partial | Good in theory, short life | Partial | 100% recyclable, recycled content |
No single material is the right answer for every situation, but the spread between the four options is significant. Cardboard is a temporary solution. Wood is a familiar one that has not kept up with the demands of modern programs.
Metal is overbuilt for impact while underperforming on chemistry, corrosion, magnetics, and weight. Engineered plastic is the only option that delivers high marks across all three families of criteria — which is why it has become the standard for exploration companies that need their core to survive from the drill rig to the archive.
FAQs
Are plastic core boxes strong enough for diamond drilling?
Yes. Engineered plastic core boxes deliver high impact resistance comparable to metal while remaining lightweight and dimensionally stable. They are designed to handle the weight of HQ and PQ core sizes under standard field handling conditions.
Why does non-magnetic matter for core boxes?
Many projects run magnetic susceptibility readings on the core or carry out downhole magnetic surveys. Metal boxes introduce magnetic interference that can distort those measurements. Plastic, wood, and cardboard are all non-magnetic and avoid that issue.
How does the lifetime cost of plastic compare with metal or wood?
Plastic core boxes have a competitive upfront cost and a long service life, so the cost per year of service is generally lower than wood (which requires replacement in humid environments) and lower than metal (where the upfront investment is higher and the boxes still corrode in aggressive environments).
Can plastic core boxes be recycled?
Yes. Engineered plastic trays from Coreplast are 100% recyclable and are produced using recycled material, which reduces the environmental footprint of the program over the long term.
Which material is best for tropical or coastal projects?
Plastic. Tropical and coastal sites combine humidity, UV exposure, salt, and aggressive chemistry — exactly the combination that destroys wood and cardboard and corrodes metal. Plastic core trays resist all four conditions without degradation.
