Spill containment on mine sites: AS 1940 & AS 3780 basics
On a mine site, bunded pallets, spill bases and rigid bulk bins keep diesel, oils, acids and processing reagents contained before a leak becomes a reportable incident. Under AS 1940 the compliant capacity is 100% of the largest container plus 25% of the aggregate stored (to the first tier) — not the "110%" rule of thumb. This guide covers which standard governs what, how to size containment, which dangerous-goods class needs which gear, and how to keep a bund compliant once it is in service.
Why spill containment is a legal duty, not a nicety
Spill containment on a mine site is a work health and safety obligation, not an optional housekeeping measure. A single split IBC of diesel or a leaking drum of flotation reagent that reaches soil, a drain or a watercourse can trigger an environmental notice, a clean-up bill and lost operating time. Containment that holds the spill at the point of storage is the control that keeps a minor leak from becoming all of that.
The model Work Health and Safety Regulations require a person conducting a business or undertaking that handles hazardous chemicals to provide a spill containment system so that spills and leaks are contained and cleaned up, and do not create a risk to health or safety (safeworkaustralia.gov.au). On a resources site that duty lands on diesel, hydraulic and lube oils, fuels, acids and the reagents used in processing — every one of which has to sit on or in something that will catch a failure.
The reason the duty is framed around containment rather than clean-up is that the cheapest litre of spill to deal with is the one that never leaves the bund. Once a hydrocarbon or reagent soaks into ground or reaches a sediment dam, remediation moves from a rag and an absorbent boom to excavated soil, laboratory testing and a regulator's sign-off — orders of magnitude more cost and downtime. Passive containment at the point of storage is the control that keeps the incident on the small side of that line, which is why auditors look for it first and why it is specified as a system, not an afterthought.
Which Australian Standard applies to what?
Two Australian Standards usually drive containment on site, sorted by what the liquid is. AS 1940 governs the storage and handling of flammable and combustible liquids — diesel, petrol, oils and solvents. AS 3780 governs corrosive substances — the acids and caustics common in processing and water treatment. Both work to the same principle: a compliant bund must hold a defined proportion of what sits above it, so a split container cannot reach ground, drains or watercourses.
The third standard people conflate with these two is AS 4084 (steel storage racking), which governs the rack, not the spill — relevant only when bunded units or bulk bins go into racking and you need to confirm the pallet's rack rating. If that is your situation, the load side is covered in plastic pallet load ratings: static vs dynamic vs racking. For spill duty itself, AS 1940 and AS 3780 are the two that matter.
How much containment does AS 1940 actually require?
AS 1940:2017 (Clause 5.9) builds the required capacity up by addition, not as a single flat percentage. For a spill compound the containment capacity is the sum of a fixed share of the biggest container and a sliding share of everything stored:
- 100% of the volume of the largest single container in the bund, plus
- 25% of the aggregate stored, for storage up to 10,000 L (the proportion steps down in higher tiers).
This is additive — the "largest container" share and the "percentage of aggregate" share stack on top of each other (standards.org.au). The widely repeated "110% of the largest container" is a rule of thumb that only happens to land near the real answer for a single container. Put four 1,000 L IBCs on one bund and the maths separates the two:
| On the bund | Aggregate stored | "110%" shorthand | AS 1940 actual (100% largest + 25% aggregate) | Shortfall if you trust the myth |
|---|---|---|---|---|
| 1 × 1,000 L IBC | 1,000 L | 1,100 L | 1,000 + 250 = 1,250 L | 150 L |
| 2 × 1,000 L IBC | 2,000 L | 1,100 L | 1,000 + 500 = 1,500 L | 400 L |
| 4 × 1,000 L IBC | 4,000 L | 1,100 L | 1,000 + 1,000 = 2,000 L | 900 L |
| 6 × 205 L drums | 1,230 L | 225 L | 205 + 308 = 513 L | 288 L |
The pattern is the point: the more containers you stand on a single bund, the worse the "110%" shorthand under-sizes it. Work the full method — including displacement and the corrosives case under AS 3780 — in IBC bund sizing: what AS 1940 actually requires, and always confirm against the current standard.
Which DG class needs which containment?
The dangerous-goods class decides both the governing standard and what the containment may be made of. Flammable Class I liquids need non-combustible containment and rule plastic out; combustible Class II/III liquids and many Class 8 corrosives are where chemically resistant HDPE belongs, provided the polymer is rated for the specific substance. Corrosive acids and caustics are governed by AS 3780, which sets containment and segregation requirements for Class 8 substances and is the standard a processing or water-treatment area is audited against (standards.org.au). The matrix below maps the common mine-site liquids to the right standard and the right BulkPlasticBins format.
| Substance on site | Typical DG class | Governing standard | HDPE containment suitable? | Format that fits |
|---|---|---|---|---|
| Petrol / low-flash solvents | Class 3, PG I (flammable) | AS 1940 | No — needs non-combustible | Fire-rated metal/concrete bund |
| Diesel, fuel oil | Class 3 (combustible C1/C2) | AS 1940 | Yes | Bunded pallet / IBC spill base |
| Hydraulic & lube oils | Combustible | AS 1940 | Yes | Bunded pallet under drums |
| Sulphuric / hydrochloric acid | Class 8 (corrosive) | AS 3780 | Yes, if rated for the acid | Compatible HDPE spill base |
| Caustic soda (sodium hydroxide) | Class 8 (corrosive) | AS 3780 | Yes, if rated | HDPE spill base, segregated |
| Dry / granular flotation reagent | Varies (often non-DG solid) | Site DG & environmental plan | Yes | Rigid solid-wall bulk bin |
The two rules that fall out of the matrix: never put a Class I flammable on plastic, and never assume one HDPE grade resists every reagent — match it to the SDS. For the combustible and corrosive rows, a chemically resistant polyethylene base is the workhorse, and a rigid solid-wall bin is what catches dry reagent and contaminated material.
Bunded pallets vs spill bases vs rigid bulk bins
Three formats cover most mine-site containment, and they are not interchangeable. Choosing the right one starts with what is leaking — drips from drums, a full IBC failure, or contaminated solids and reagent that need capturing and moving.
- Bunded pallets sit under drums and small containers, with a sump that catches drips and spills while keeping the containers up out of any captured liquid.
- IBC spill bases are sized for one or two IBCs of reagent, diesel or oil, holding the standard's required share of the largest container.
- Rigid solid-wall bulk bins capture dry or granular reagent, contaminated soil and spill-response material, and move it by forklift without leaking through seams.
For the drum-deck role, a heavy-duty Australian Standard pallet gives you a rackable, wash-down platform rated to carry a full set of drums and stand up to forklift abuse, dust and UV. The 1165 × 1165 mm footprint is the one Australian racking and dock gear is built around — the reasoning is set out across the plastic pallet range.
When the job is capturing dry reagent, contaminated soil or spill-response waste rather than holding a liquid above a sump, a rigid one-piece bulk bin is the format that travels. A solid-wall ISO-footprint container holds the material, takes a forklift on four-way entry, and folds flat for the return leg so empty back-haul does not eat freight — which matters on remote sites. The recycling and resource-recovery range leans on exactly this kind of weatherproof, UV-stable bin; see how those operations spec it on the recycling industry page.
Why does HDPE survive where steel and timber fail?
High-density polyethylene shrugs off the three things that destroy handling gear on a mine site: corrosion, rot and chemical attack. Steel spill bases rust where acids and salts sit; timber pallets soak up diesel and oil, rot and shed splinters into the load; and both degrade fast under constant UV and heat. HDPE does none of that, and it washes down clean between reagents so a base that held diesel can be reassigned without cross-contamination.
The one specification that separates a good outdoor unit from a bad one is UV stabilisation. Un-stabilised polyethylene goes chalky and brittle in the sun and eventually cracks — a containment failure waiting to happen on an open pad. On a Pilbara or Bowen Basin site, a UV-stabilised grade is not a nice-to-have; it is the difference between a bund that lasts years and one that fails in a season. When you brief us, say the unit lives outdoors and we spec the grade for it.
Chemical compatibility is the other specification that does not show up in a photo. HDPE resists most diesel, oils and a wide band of acids and caustics, but no single polymer is inert to everything — strong oxidisers and certain solvents attack it over time. The practical workflow is to read the Safety Data Sheet for the reagent, confirm the polymer is rated for that substance at the concentration and temperature it is stored at, and label the base so a unit that held one reagent is not blindly reused for an incompatible one. Get that right and an HDPE base outlasts several steel equivalents on the same pad; get it wrong and a chemically attacked base fails quietly, which is the worst way for containment to fail.
How do you keep a bund compliant in service?
Sizing the bund correctly is only the start — a compliant bund stays compliant only if it is maintained. The capacity printed on a spec sheet assumes an empty, clean sump; rain, displacement and incompatible storage all erode it in the field. The practices below keep the rated capacity real:
- Size to the standard, then add margin for rain on open outdoor units, and drain captured clean water before it steals capacity.
- Subtract displacement of drums, IBC frames, pallets and plinths standing inside the bund — usable capacity is less than the empty geometric volume.
- Keep incompatible substances apart — acids and flammables, or reactive reagents, never share a bund.
- Inspect on a schedule for cracks, debris and captured water, and log it so the control is auditable.
- Match the format to the class — a fire-rated bund for flammables, HDPE for combustibles and rated corrosives, a rigid bin for solids.
See our mining range for bunded options, spill bases and reagent IBCs, or tell us your dangerous goods — the substance, the container sizes and how many sit together — and we will spec containment that meets the standard for your site.
Common questions
Is the "110% of the largest container" bund rule correct for mine sites?
No. It is a rule of thumb that lands near the right answer for a single container, but AS 1940:2017 actually requires 100% of the largest single container plus 25% of the aggregate stored, up to 10,000 L. On a bund holding several IBCs or drums of diesel or reagent, the real figure is meaningfully higher than 110% — which is exactly the case where under-sizing reaches the drains.
Can I store mine-site flammables on a plastic spill pallet?
Not Class I flammable liquids such as petrol or many solvents — those need non-combustible, fire-rated containment. HDPE bunded pallets and spill bases are suited to Class II/III combustible liquids like diesel and most oils, and to many reagents where the polymer is rated for the specific substance. Corrosive acids and caustics fall under AS 3780; confirm chemical compatibility before you commit.
How much containment does one 1,000 L IBC of diesel need?
Under AS 1940:2017, at least 100% of 1,000 L plus 25% of the 1,000 L aggregate — about 1,250 L of usable containment — before you add a rain margin for an outdoor unit and subtract the volume the IBC frame and pallet displace inside the bund. The worked maths is in IBC bund sizing: what AS 1940 actually requires.
Do bunds need to handle rainwater on an open mine site?
Yes. An uncovered bund collects rain, and every litre of water sitting in the sump is a litre less spill capacity. Open outdoor bunds should be sized with a rainfall allowance for the site, inspected on a schedule, and drained of clean captured water — through a controlled, checked release — before it eats into the rated containment volume.
Why use plastic containment instead of a concrete or steel bund?
Fixed concrete bunds suit permanent tank farms, but mine layouts move. Polyethylene bunded pallets, spill bases and rigid bins are portable, chemically resistant, will not corrode like steel or crack and spall like ageing concrete, and wash down clean between reagents. They let you put compliant containment exactly where the drums and IBCs are this month, then relocate it next month.
Source: AS 1940:2017 The storage and handling of flammable and combustible liquids (Clause 5.9 spill compounding) and AS 3780 The storage and handling of corrosive substances, Standards Australia; model Work Health and Safety Regulations spill-containment duty, Safe Work Australia. Capacity figures and the DG matrix are general guidance synthesised for Australian operators — verify against the current standard, each product's Safety Data Sheet and your state's dangerous-goods regulations. Not a compliance certification or a quote.