Los Santos lies within Lower Palaeozoic sediments in the Central Iberian Tectonic Zone, which forms part of a Europe-wide, Variscan age orogenic belt. The stratigraphy comprises a thick sequence of clastic metasediments, ortho- and para-gneisses, with volcanic andcarbonate formations.

The Los Santos deposit is a typical skarn-hosted scheelite deposit, where intrusion of granitoids into carbonate-rich sedimentary rocks has resulted in their replacement by calcsilicateor siliceous minerals, together with mineralisation.

The deposit has been divided into a number of zones, six of which form the basis of the current project. From west to east these are known as Las Cortinas, Sector Central, Capa East and Los Santos Sur. The strike length varies for each zone and zone dips are fairly uniform across the deposit varying between 60o to 90o.

Within each zone, the skarn mineralisation is located within a number of individual beds, separated by barren lithologies. The major skarn beds vary between 2m and 20m in width; there are, however, numerous thinner bands measuring tens of centimetres.

Within each zone, the skarn mineralisation is located within a number of individual beds, separated by barren lithologies. The major skarn beds vary between 2m and 20m in width; there are, however, numerous thinner bands measuring tens of centimetr.

There are several varieties of skarn mineralisation, economically the most important being the ........

The open pit operations are conventional drill and blast operations, using mining contractors.

Mining operations are based on mining 10m benches in waste, and 5m benches in ore, with 0.5m of sub-drilling. Tamrock CHA1100 rigs are used for blasthole drilling. The blastholes are 3.5 in. in diameter, and drilled on a 3m x 2.5m pattern in Los Santos Sur, and a 3m x 2.5m pattern in the other pits.

Pre-split lines are drilled along the edges of final walls. These pre-split holes are 3 in. in diameter, and are 0.8m apart.

The night following every blasting containing ore, a team of geologists checks with ultra-violet (UV) lighting the real position of the ore after blasting displacement, in order to reduce dilution to the minimum. They also pass the UV lamp by the waste dumps and stockpiles, to check for any kind of error on ore/waste selection. During all ore mucking operations, a grade control geologist is always present, to check and check for any other variations that can be seen in the pit with the blasted skarn material.

Pit production stopped in April 2019. Tailings were then re-processed from April 2019 to January 2020, when the processing operations were temporarily suspended.

Almonty continued its work with third party consultants in evaluating its tailings reprocessing methodology, running bulk samples through the existing plant as well as continued sampling through a testing circuit. The tailings recovery rate con ........

- subscription is required.

The process plant is primarily based on gravimetric separation, aimed at recovering a high grade scheelite concentrate.

Two banks of hydrocyclones then split the gravity circuit feed material into 1,000/150 µm and 150/30 µm size fractions. Both size fractions go through low intensity magnetic separation to remove mill steel and pyrrhotite ahead of gravity separation.

The non-magnetics streams from the two size fractions then go to their respective banks of rougher spirals. Middlings are recycled via middlings-cleaners spirals, and the rough spiral tails exit as waste. In both circuits, rougher concentrates are cleaned in a bank of cleaner spirals before going forward to shaking tables. Concentrates from the coarse and fines spirals are fed to a hydrosizer which feeds four separate tabling circuits. Tailings from the cleaner step of all tabling circuits are recycled back to the hydrosizer.

The coarse tailings are dewatered by thickening cyclones and a hi ........