The Juanicipio silver-gold project is an underground project being developed in the Fresnillo District of Zacatecas, Mexico.
The mine is expected to produce an average of 11.7 million ounces (Moz) of silver and 43,500 ounces (oz) of gold a year through its initial anticipated mine life of 12 years. It is expected to create 2,750 construction jobs and 1,720 operational jobs.
Minera Juanicipio, a joint venture between Fresnillo (56%) and MAG Silver (44%), is the project owner and developer. Fresnillo will develop and operate the project on behalf of the JV.
The project is estimated to require a pre-production capital cost of $360m, with an additional $480m for sustaining capital.
It secured all the permits from the respective developer company boards in April 2019 and anticipated to see the start of construction immediately. The construction is expected to be completed by the end of 2020.
Juanicipio silver-gold project location, geology, and mineralization
The Juanicipio silver-gold project is located in central Zacatecas State and is accessible through 6km-long paved and dirt roads.
The property is located within a 7,679.21ha mining concession, while an additional 312.12ha of surface rights lying north of the existing concession were acquired as part of the project development.
The project hosts two types of vein systems namely Valdecañas and Juanicipio, with the former further divided into five veins.
Multiple mineralizing events are believed to have occurred at the Valdecañas vein system. Majority of the silver and gold are hosted at the top (named as Bonanza Zone), while lead and zinc are found in the deeper reaches (called Deep Zone). Copper is identified at the deepest levels of the project.
The project was estimated to contain indicated mineral resources of 12.83 million tons (Mt) grading 427g/t Ag, 2.10g/t Au, 2.11% Pb, 3.68% Zn, 0.13% Cu as of October 2017.
Mining at Juanicipio silver-gold project
The Juanicipio silver-gold mining project will employ longhole stope mining method, using modern trackless mining equipment. Set to operate at a proposed mining rate of 4,000 tons per day (tpd), the project will apply cemented rock fill method in the wider stopes requiring more than one longitudinal pass.
Access to the mine is through twin declines located on top of the mineralization, which will further be split into three ramps on a sub-level spacing of 20m. The plan involves mining of 20m-high stopes (floor-to-floor) back to the central access, with rock fill placed within 20m of the blasting face.
Mining will take place in two longitudinal passes with a maximum width of 15m at the lower levels. The mineralized material will be handled by a 780m-long winze, which is anticipated to be operational from the eight year.
The processing plant will feature a comminution circuit and will produce separate silver-rich lead, zinc, and gold-rich pyrite concentrates.
Mineralized rock from development and stoping will be fed to an underground crusher and transferred to the surface for milling, through a main conveyor.
The crushed and milled ore will be stockpiled before being delivered to the mill through conveyors. The mill will comprise a semi autogenous (SAG) grinding and ball mill, which produces feed for the flotation circuit.
The resultant lead, zinc, and pyrite concentrates from the flotation circuit will be thickened, filtered, and stockpiled. The concentrates will be shipped directly to the customers.
The processing will be ramped up to 1.4Mtpa over a three-year period with the recovery rates being 95% silver, 82% gold, 93% lead, and 90% zinc.
A 6.5km access road will be constructed to connect the plant with the main decline portal and a 1.5km access road to connect the highway to the processing plant. A special two-lane sealed road to be used by heavy vehicles will also be built.
A 1.5km, 115kV overhead power line from the local grid will supply power to the substation at the site.
Initial water supply will be made from the neighboring mine, while additional ground water supply will be made through a pipeline. Dewatering of underground workings at the project is also proposed to identify water sources.
AMC Mining Consultants (Canada) prepared the NI 43-101 Technical Report of the Juanicipio project.