Leaching Phases 8 and 9 expansion — Veladero Mine (gold)

What is approved is, literally, new lined surface: two further phases of valley leaching. The pad is a lining job where the critical work is not the material but the welding of the geomembrane and its testing, because a badly made seam is a solution leak. Catamarca already has this same service measured as a niche of its own for lithium ponds; San Juan, with a gold mine expanding pads, does not, and certified installation is brought in by crews from outside the province. The window is construction of the phases, not operation.

Valley leaching recovers the gold with cyanide solution in a closed circuit, so expanding phases 8 and 9 expands the circuit that has to be contained, monitored and audited: balance of rich and barren solutions, leak detection, barrier control and periodic external audit under the international standard the industry requires in order to sell. It is a permanent obligation and not a construction cost, and independent audit capacity in the province is scarce: whoever provides it is often the same party that designed the installation.

A valley leach pad is a structure that grows in height while it is being loaded, in a seismic, high-mountain area. Its stability is not verified once at design stage: it is instrumented and measured while it operates, with piezometers, inclinometers and topographic deformation control. The province's road works and earthmoving niche measures construction; the instrumented monitoring that runs afterwards, throughout the life of the pad, has nobody quantifying it and no local supplier.