The Toqui deposits were discovered in the early 1970's. The three original deposits at Toqui, Doña Rosa, Mallín-Monica and San Antonio adjoin each other but are separated by faults. The Toqui property encompasses an area of approximately 1,800 square kilometres. This area includes the Doña Rosa zinc-gold mine, Rosa West zinc-lead mine, the San Antonio East and Mallín-Mónica and Mallín South zinc mines, the Aserradero and Mina Profunda gold-zinc mines.

Zinc/gold mineralisation at Toqui occurs as manto deposits hosted by an 8 metre to 12 metre thick bed of fossiliferous limestone, known as the Main Manto unit. The Toqui deposits all dip gently to the south, and most deposits are amenable to room and pillar mining, with 11 metre rooms around 8 metre pillars. The Mina Profunda deposit and the Porvenir deposit are mined by a 'drift and fill' method, due to the steeper dip of these deposits.

Mining is normally carried out in a single horizon from flat lying mineralisation varying in thickness from four to 12 metres, except where localised faulting may offset the manto into smaller stopes accessed via mine ramps. In Estatuas, there is a lower secondary manto which has economic zinc grades and is being mined.