Sepon Limestone Tank

Sepon Limestone Tank


LXML is a joint venture between Australian miner OZ Minerals and the Laos government. In 2003 LXML added a Copper mine and processing plant to its existing gold operation. The Copper Plant produces in excess of 60,000 tonne each year. From leaching of the ore to solvent extraction fnally to onsite electrowining copper cathodes are produced with a 99.999% pure copper content.

Operating Conditions

The treatment of primary ore to extract copper is a chemical process using atmospheric leach technologies, corrosive materials such as Sulphuric Acid, solvents and organic chemicals. Part of the process is the use of Limestone slurry prepared in steel tanks for neutralization of process liquids. The Limestone tank is in the “Super Loop” and is a critical part of the process.

The project is in a remote location with heavy rainfall and high humidity. Sepon project was a logistical challenge this work was completed during a plant shutdown with a tight turnaround schedule.

Special Requirements

The existing coating specifcation had failed due to high erosion, which had removed the existing coating followed by high corrosion and pitting. In many places the steel shell and baffles were severely corroded. This tank had to be prepared and the new lining installed and cured in a short window as the work was carried out during a planned shutdown.

Corrosion Protection

The client decided to remove the old coating and install the new lining to ½ of the tank from the floor up to maintain the shutdown schedule and repair the upper level at a later date. Following high pressure washing, garnet blasting a repair and lining system designed and installed by Trepax was installed to the floor plate, walls, baffles and mixer.


To meet the erosion and corrosion requirements a glass reinforced vinyl ester lining was applied to all surface followed by an aluminium topcoat.

The original paint lasted less than 12 months, the new lining system as intended is defect free to date confrmed by regular inspections during plant shutdowns. The lining if maintained properly is expected to last the service lifetime of the tank.

Project Details

Location Savanakhet, Laos PDR
Project Sepon Copper Mine
Owner LXML Company Limited
EPC Khanong Development Group
Date 2005
Work Limestone Slurry Tank
System Vinyl Ester Lining
Area 250 m2
Value US$ 65,000