San Rafael Las Flores, Guatemala
El Escobal Mine is one of the largest and most modern silver mines on the globe. The project is located approximately 40 kilometers southeast of Guatemala City close to the town of San Rafael Las Flores in the department of Santa Rosa. Since 2010 the mineral resource of Escobal has grown substantially and the mine was commissioned in 2014 having a mineral base of over 36 million tons grading over 330 grams per ton silver and interesting by-products such as gold, lead and zinc.
In order to achieve the high ore throughput levels of 4,500 tons per day, of which half will be put back underground in form of cemented paste fill, the mine needs an efficient in-cycle support installation for rapid development rates. From the very beginning, one of the main challenges was to provide enough underground production headings in order to source enough ore feed for the hungry mill on surface.
Hence, multiple ore development headings are driven simultaneously in sometimes difficult ground conditions that require good shotcrete support designs and a spray application that is fully integrated into the mining cycle. Shotcrete in combination with extensive meshing and structural fibers give good yielding capabilities for the primary shotcrete support and allow fast re-entry times into the secured perimeters.
Specific project requirements included:
Rapid early strength development
High final strength
A maximum dosage of accelerator of 10%
A product stability of minimum six months
Open time > 2h
High Energy absorption according to ASTM 1550-05
Sika's world leading Sigunit® and ViscoCrete® technology is among the key elements for the shotcrete and concrete works at Escobal. For the shotcrete, Escobal relies on the proven Sika Sigunit® L50 AFX, alkali-free accelerator that has stable properties and is a high performing product when it comes to rapid early strength development.
Sika Guatemala is not only supplying mine consumables but is also present on site to give ongoing support with everything related to underground construction. Together with the dedicated San Rafael team, many challenges have been tackled with good results from the early days of mining at Escobal.
Sika® ViscoCrete®-2100 SuperplastIcizer
Sika ViscoFlow®-50 Slump retainer
SikaTard®-930 Consistency stabilizer
Sigunit® L50 AFX Alkali-free, high-performance shotcrete accelerator
SikaPump® Paste backfill admixture
Tahoe Resources, Minera San Rafael