La India achieved commercial production on February 1, 2014, and has a mine life of approximately six more years. Our Pinos Altos and Creston Mascota mine complex is approximately 70 km southeast of La India, providing operating synergy between the two properties.
2016 production and costs
Production - 115,162 oz
Production costs - $432 oz/gold
Total cash costs - $395 oz/gold
The La India mine is located approximately 200 km east of Hermosillo in Sonora, Mexico. The 632-square km property includes the La India mine site, the Tarachi gold resource and several other prospective exploration targets, situated in the prolific Mulatos gold belt. The La India mine hosts proven and probable reserves of 1.0 million ounces of gold contained within 44 million tonnes of ore grading 0.72 g/t gold as of December 31, 2016. The mine expects to achieve 100,000 ounces of gold production in 2017, and an average annual production rate of 110,000 ounces gold from 2018 to 2019.
With the increased mineral reserves and mineral resources, and potential for future additions at other satellite zones, studies are underway to look at potential expansion options at La India.
The La India mine lies within an extensive ancient volcanic field. It is in an area dominated by outcrops of volcanic tuffs from different explosive volcanic events that were affected by large-scale north-northwest-striking faults and intruded by granodiorite and diorite stocks. Canyons cut through the uppermost layers to expose the Lower Series volcanic strata.
La India lies in a large area of intrusion-related alteration dominated by high-sulphidation epithermal-style gold mineralization. The gold mineralization is confined to zones of argillitic alteration originally containing sulphides and subsequently oxidized. La India’s reserves are in oxide and sulphide material amenable to heap leaching. The gold system at Tarachi is best classified as a wallrock gold porphyry deposit, comprising sheeted veins that deposited gold within the wallrock outside the source dacite porphyry intrusions, suggesting that it has the potential to grow into a much larger deposit.
The La India mine is a collection of deposits grouped into three open pits – North, La India (Central) and Main – that are being mined over an estimated six-year life, providing ore for a heap leach pad located just west of the North pit. The mining rate is expected to be approximately 16,000 tonnes/day with a stripping ratio of approximately 1:1.
La India’s processing flow includes a three-stage crushing process followed by a heap leach operation. The leach pad has a capacity of up to 50 million dry tonnes, reaching an ultimate height of approximately 113 metres. Cyanide leach solution percolates through the heap to the lined solution-collection ditch that routes it to a double-lined pregnant collection pond. A zero discharge water balance is maintained at the heap leach facilities. The gold adsorption facility (ADR plant) consists of two parallel trains of five 3.5-tonne carbon adsorption columns and a Zadra strip with electrowinning. Gold-silver doré bars are produced in the refinery. The plant is designed to process leach flows from up to 6.0 million dry tonnes of ore per year (16,438 tonnes/day). Gold recovery is estimated at 80% with a 90-day leach time.
Additional drilling was carried out at La India in 2016, with a focus on extending mineralization in the Main Zone and the La India Zone and conversion of sulphide mineralization into mineral reserves and mineral resources. The 2016 exploration program resulted in an 18% increase of gold in mineral reserves and a 5% increase in measured and indicated mineral resources.
Step-out drilling in 2016 at the nearby El Realito project also yielded encouraging results. Additional exploration work is planned at the El Realito, Cerro de Oro and Los Tubos areas to define drill targets for 2017. In 2017, the Company expects to spend $6.9 million on 31,000 metres of exploration drilling and $0.8 million on 5,000 metres of conversion drilling at La India.
The Tarachi property is part of a large land package that surrounds Agnico’s La India mine in the Mulatos district of Sonora, Mexico. Tarachi is a large low-grade gold porphyry deposit with satellite epithermal mineral occurrences discovered in 2010.