Background

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 and strong acids such Sulphuric Acid. The ore is processed as slurry and has signifcant erosive qualities. The CCD tank train prepares the ore slurries for further processing up stream. Each tank is a large concrete on ground structure with a 30m diameter and 7m in height.

The project is in a remote location with heavy rainfall and high humidity. Sepon project was a logistical challenge and special heavy duty protection was used to protect the areas from rainfall and maintain the tight installation schedule.

Special Requirements

To protect the concrete CCD structures from the erosive and corrosive effects of the acidic slurry specially designed protective linings where used. During engineering of the project ground settlement and secondary containment issues lead to the use of a crack bridging membrane being used prior to the corrosion protection barrier.

Corrosion Protection

Constant immersion of the CCD tank surfaces in corrosive media meant a high quality lining system had to be used to realize the 20 year lifetime goal of the project. This lining as well as resisting corrosion had to withstand high erosion and maintain suffcient thickness to meet the projects service life.

System

To meet the requirements of secondary protection and reduce the risk of contamination from settlement induced cracking of the tanks an elastomeric polymer membrane was used, which was protected by a glass reinforced vinyl ester chemical resistant barrier and fnally surfaced with a highly abrasive resistant aluminium oxide flled vinyl ester top coat. We also designed, supplied and installed a work shop fabricated FRP launder and overflow system to the CCD tank train.

Project Details

Location	Savanakhet, Laos PDR
Project	Sepon Copper Mine
Owner	LXML Company Limited
EPC	Khanong Development Group
Date	2004
Work	Concrete CCD Thickeners
System	Multi Layer Vinyl Ester Lining
Area	12,000 m2
Value	US$ 2.5 Million