Underground mine construction Newmont Waihi gold mine at Favona in Waihi New Zealand began in late in 2004 on the decline for the Favona underground operation. While some ore was mined during construction, full ore production from stopes began in 2006. Currently ore from underground and from the  Martha open pit are both fed to the processing plant and treated alternately.

The Favona underground gold mine is located on the east coast of New Zealand’s north island. Newmont Waihi Gold is wholly-owned by Newmont Mining Corporation, which is based in Colorado, USA, is one of the world's foremost gold producers with operations and exploration projects on five continents

Favona Mine Produces Around 400,000 Tonnes of ore Annually During the last 10 years of operation the Favona mining activities have mined around 400,000 tonnes of gold bearing ore annually as well as an average of about 7,000 metres of horizontal development each year with 100,000 metres of production drilling. Ongoing mining activity at the Favona operation has included backfilling, de-watering, the installation of ground support that comprises meshing, strapping and rock bolting. Work at the mine also includes drilling blasting and excavation of the ore along with vertical and level portal and decline development.

Modern mechanised mining operates from the bottom up. Mining began at Favona at a depth of 335 metres below the surface. Mined out areas (stopes) are backfilled so that  can access upwards the next level of the ore. Filling provides lasting stability and no large voids are left behind - as was common in the historic Martha underground mine.

The backfilling gives stability to the mining taking place overhead with no large voids being left behind. This mining technique was also used successfully at the nearby Martha underground workings.

The now mined out Trio underground mine was also accessed through the Favona portal. Mining began at the Trio mine in 2012 and it produced about 200,000 ounces of gold from the mining of one million tonnes of ore before it closed in 2014.