FRP Grating Case Study | Mining Leaching & Solvent Extraction Platform — ZeAllgrate
Mining & Metallurgy — Project Background
A copper mining and solvent extraction (SX/EW) operation required replacement access platforms and walkways around its leaching ponds, mixer-settler contactors and organic solvent storage area. The previous steel grating and platforms had corroded within 4 years under continuous exposure to dilute sulfuric acid (pH ~1.5) and organic extractant solvents, producing recurring safety hazards and high maintenance costs. In the solvent extraction area, steel also presented a sparking risk around flammable organic vapors. The operator needed a single material that would survive acid, solvent and outdoor UV exposure, and that would not spark in the SX area.
Engineering specified vinyl ester molded grating for the acid areas and solvent -resistant pultruded grating for the long spans over the mixer-settler trains, with all stainless fasteners. Client identity is kept confidential; the project is described as Confidential Client, a copper SX/EW operator in Southeast Asia.
Engineering Specification
Working values agreed with the client's engineering team during design review.
| Parameter | Selected Value | Standard / Reference |
|---|---|---|
| Live load | 4.0 kN/m² (operators + maintenance) | Mining plant design basis / EN 1991-1-1 |
| Clear span — leaching | 1.0 m between tank rails | ZeAllgrate molded grating design guide |
| Clear span — SX area | 1.5 m between supports | ZeAllgrate pultruded grating design guide |
| Deflection limit | L/150 at design load | ZeAllgrate standard |
| Resin system | ZeAll VE (vinyl ester) | H₂SO₄ 20% / organic solvent resistance |
| Panel — leaching | 38 mm molded, grit-top | ZeAllgrate standard molded grating |
| Panel — SX area | 50 mm pultruded, grit-top | ZeAllgrate pultruded grating |
| Surface | Grit-top bonded quartz | Wet / acid-spill anti-slip |
| Fixings | SS316 clips and brackets | ASTM A276 316 |
| Spark resistance | Non-sparking in SX area | Mining safety / flammable vapor requirement |
What Was Supplied and How It Went In
ZeAllgrate supplied 1,200 m² total: 800 m² of 38 mm ZeAll VE molded grating for the leaching pond walkways and 400 m² of 50 mm ZeAll VE pultruded grating for the mixer-settler train access. All panels were delivered with acid-immersion test reports against the operator's process chemical list, and custom cut-outs were fabricated around agitator bases and pipe runs. The grit-top surface handles acid and solvent spills without becoming slippery, and the non-sparking FRP bearing bars eliminate the ignition risk in the solvent extraction area.
Installation was staged across planned plant shutdowns so the leaching and SX trains never lost production capacity. Because FRP is roughly 75% lighter than steel, panels were hand-carried to the tank-top areas where crane access was not available.
FRP grating walkway over mining leaching pond
50 mm pultruded vinyl ester grating for SX area spans
38 mm vinyl ester molded grating for acid service
Outcomes and Inspection Findings
At 3-year inspection, the mining operator reported zero corrosion on FRP panels and SS316 hardware, no delamination, and no coating breakdown. The platforms have held up under continuous acid and solvent exposure with no replacement work.
- Corrosion: zero H₂SO₄ or organic solvent attack after 3 years; previous steel required replacement within 4 years.
- Safety: non-sparking FRP in the SX area; no ignition incidents attributed to the new platforms.
- Slip: grit-top surface retained wet COF > 0.7 (ASTM F1679) at inspection.
- Maintenance: zero painting, zero patching; estimated ~50% reduction in platform maintenance costs over 10 years.
- Service life: expected 25 years vs. 4 years for the previous steel platforms.
Engineering Notes
Leaching and solvent plants concentrate the corrosive load: strong acid at the leach tanks, solvent and electrolyte at the electrowinning decks, and concentrated foot and machinery loads on the walkways. The specification uses vinyl ester for the acid zones, pultruded grating where long spans demand stiffness, and grit-top where the deck is wet and muddy. SS316 hardware is specified throughout, and the deck is checked against both the uniform and concentrated load cases at the actual span.
What to Specify
- Vinyl ester for leach and electrowinning acid service.
- Pultruded grating for long spans and high stiffness.
- Grit-top on wet, muddy traffic surfaces.
- SS316 hardware; both load cases checked at the span.
- Vinyl ester for leach and electrowinning acid service.
- Pultruded grating for long spans and high stiffness.
- Grit-top on wet, muddy traffic surfaces.
- SS316 hardware; both load cases checked at the span.
Planning a Similar FRP Grating Project?
Send us your layout drawings, service chemicals and span requirements — ZeAllgrate will return a design proposal, load calculation and reference pricing within 48 hours.
- ZeAllgrate molded and pultruded grating design guides, load and deflection tables.
- ASTM F1679 — Standard Test Method for Measuring the Dynamic Coefficient of Friction on Walking Surfaces.
- Mining safety guidance on non-sparking materials in solvent extraction areas.
- ASTM G20 / NACE — laboratory immersion testing of plastics in acids and solvents.
- Project inspection records supplied by Confidential Client; values quoted as-reported.