Riotinto Expansion Project

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Mine TypeOpen Pit & Underground
  • Copper
  • Zinc
  • Lead
Mining Method
  • Truck & Shovel / Loader
  • Sub-level stoping
  • Blast Hole Stoping
Backfill type ... Lock
Mine Life... Lock
SnapshotOn 23 February 2023, Atalaya announced the results from a new preliminary economic assessment for the Cerro Colorado, San Dionisio and San Antonio deposits at its Proyecto Riotinto.

The Riotinto PEA serves as a foundation for further optimisation, including the potential application of the E-LIX System.

Proyecto Riotinto includes the Cerro Colorado open pit mine and a modern 15Mtpa processing plant, which has the potential to become a processing hub from projects currently in the permitting stage.
Related AssetRiotinto


Atalaya Mining Plc. 100 % Indirect
Atalaya Riotionto Minera, S.L.U. (operator) 100 % Direct
The main operating subsidiary of Atalaya Mining Plc is the 100% owned Atalaya Riotinto Minera, S.L.U. which owns and operates Proyecto Riotinto.



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Deposit type

  • VMS
  • Breccia pipe / Stockwork


Deposit Types
Rio Tinto is a Volcanogenic Massive Sulfide (VMS) deposit located in the IPB (Iberian Pyrite Belt), which forms part of the Hercynian orogenic belt.

In the Rio Tinto area, mineralization occurs in five separate zones along the anticline: San Dionisio, Cerro Colorado - Filón Sur - Filón Norte, and Planes-San Antonio. Mineralization is typical of the VMS deposits and occurs as three different types of mineralization: sulfide stockworks in the volcanic rocks, massive sulfide orebodies, generally, on top of the stockwork zones and/orintercalated with rocks of the transition series, and weathering products of the mentioned primary mineralization types which are represented by gossans and secondary enrichment zones. The latter are restricted to within 70 m of the surface (Palomero, 1990).

Sulfide Stockwork
The stockworks occur as irregular veins, fractures, and fissures filled with quartz and sulfides (pyrite, chalcopyrite, galena, sphalerite), magnetite, quartz, chlorite, calcite, and barite cutting the volcanic host rocks. The top of the stockwork marks the base of the massive sulfides. The veins become thicker towards the surface. Close to the massive sulfides, most stockworks are made up of veins with lesser amounts of strongly replaced volcanic rocks. The stockworks can extend up to 400 m downwards from the contact with the massive sulfides down to the basic volcanic unit.

There is a spatial zonation within the stockwork where three types of stockwork can be distinguished:
• Pyritic stockwork zones, also referred to as pyrite chimneys or pyrite feeder zones, consisting of intense pyrite mineralization and local chalcopyrite (e.g., Planes). Average sulfur content of this type of stockwork is 20%.
• The cupriferous stockwork (average 2% Cu content and 30% S). This is a vein-type mineralization with a high concentration of chalcopyrite and is usually adjacent to and parallel to the contact with the massive sulfides. This copper envelope is locally referred to as “cloritas” ( Botin & Singh, 1981). The “cloritas” stockwork is highly developed at the base of the San Dionisio massive sulfide body where veining is parallel to contact with the massive sulfides. It is also found below the Filón Sur and Filón Norte deposits.
• The lower stockwork zone consisting of a sericitic envelope restricted to the acid volcanic rocks contiguous to the “cloritas” cupriferous stockwork. Copper and sulfide contents are much lower than in the previously described stockwork types. The lower stockwork is the main mineralization of Cerro Colorado. Zone 2a described at the footwall of the “cloritas” of the Alfredo underground mine is also a stockwork of this type.

The Planes-San Antonio deposit has a poorly developed stockwork of reduced size compared with San Dionisio. A semi-massive pyrite zone without base metals is located at the base of the Planes deposit.

Massive Sulfide
Massive sulfide mineralization consists of lenses of massive pyrite overlaying the felsic volcanic and the stockworks, usually with greater lateral extent than the stockwork zones. The sulfide minerals are frequently recrystallized with relicts of primary textures within the pyrite.

The primary sulfide mineralization consists mostly of pyrite, with minor chalcopyrite, sphalerite, galena, tetrahedrite, and sulfosalts of Sb and As in intergranular spaces or in microfractures. Chalcopyrite is the dominant copper mineral and mostly occurs within small fracturesin the pyrite; on a lesser extent it occurs in isolation.

The massive sulfide deposits are present as dismembered lenses along the axis and the flanks of the anticline and are overlain by shales of the Culm series. Currently, massive sulfides remain only at San Dionisio and San Antonio. At Filón Sur, Filón Norte, and Planes the massive sulfides have almost entirely been removed by mining. In the core of the anticline at Cerro Colorado-Salomón open pit, it is believed that the deposits originally formed an almost continuouslens of massive sulfides of about 5 km long, 750 m wide, and 40 m thick, containing more than 500 million tonnes of sulfide mineralization.

The San Dionisio sulfide body is the largest deposit at Rio Tinto. It is a homogeneous pyritic body containing sphalerite and chalcopyrite with minor amounts of galena, arsenopyrite, and tetrahedrite. While the distribution of Pb-Zn is not regular, the copper content increases toward the contact with “cloritas”, and maximum copper grade isfound at the contact between the massive sulfides and “cloritas”. Thisfootwall contact is gradational to locally abrupt. The upper contact is usually sharp and mineralization in the hanging wall rocks is very rare. The San Dionisio deposit has been described in the literature as a stratiform massive sulfide orebody with a syncline shape derived from folding. An extensive study of the geology and the mineralogy of the San Dionisio sulfide body by R.A. Read in 1967 strongly indicates that the deposition of sulfides is a replacement of a favorable folded volcanic horizon.

San Dionisio Massive sulfides have been extensively mined at the Atalaya pit and the Alfredo underground mine up to the 26th floor, approximately down to 135 m elevation.

At the Planes-San Antonio deposit, the massive sulfides are planar and are represented by two orebodies. The first is the Planes deposit, which is overlying the pyrite stockwork and is completely mined out; and the second is the San Antonio deposit, which occurs outside the limits of the stockwork and isintercalated with pyroclastic volcanic rocks. The San Antonio deposit is a pyritic stratiform sheet, apparently formed as a chemical sediment on the sea floor (Williams, Stanton, & Rambaud, 1975). The San Antonio massive sulfide mineralization contains more than 40% S, is enriched in Cu, Pb, and Zn, and has a maximum thickness of 38 m. Laterally, the massive orebody splits in several bands separated by barren tuffs.

Gossans and secondary mineralization have formed in places over the stockwork and sulfide mineralization. Leaching and oxidation of an important volume of sulfides in Cerro Colorado and minor amounts in the Atalaya open pit developed extensive gossans, which were mined for gold and silver. Gossans and supergene enrichment zones are characterized by the occurrence of secondary minerals goethite-limonite and chalcocite-covellite respectively.

Gossan has also been mined at Planes 50 m west of the Planes shaft (Williams, Stanton, & Rambaud, 1975). Gossans and secondary mineralization have been mined out and are no longer a significant resource.



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Mining Methods


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Crushers and Mills

Milling equipment has not been reported.



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CommodityProductUnitsAvg. AnnualLOM
Copper Metal in concentrate M lbs 2,213
Zinc Payable metal M lbs 1,077
Zinc Metal in concentrate M lbs 1,267
Lead Payable metal M lbs 160
Lead Metal in concentrate M lbs 168
Copper Equivalent Payable metal kt 90

Operational metrics

Annual processing capacity  ....  Subscribe
Waste tonnes, LOM  ....  Subscribe
Ore tonnes mined, LOM  ....  Subscribe
Tonnes processed, LOM  ....  Subscribe
* According to 2022 study.

Production Costs

Cash costs Copper USD  ....  Subscribe
All-in sustaining costs (AISC) Copper USD  ....  Subscribe
Assumed price Lead USD  ....  Subscribe
Assumed price Zinc USD  ....  Subscribe
Assumed price Copper USD  ....  Subscribe
* According to 2022 study / presentation.
** Net of By-Product.

Operating Costs

Combined mining costs ($/t milled) USD 7.77 *  
Processing costs ($/t milled) USD  ....  Subscribe
G&A ($/t milled) USD  ....  Subscribe
Total operating costs ($/t milled) USD  ....  Subscribe
* According to 2022 study.

Project Costs

MetricsUnitsLOM Total
Sustaining CapEx $M USD  ......  Subscribe
Closure costs $M USD  ......  Subscribe
Total CapEx $M USD  ......  Subscribe
OP/UG OpEx $M USD  ......  Subscribe
Processing OpEx $M USD 1,962
Refining and transportation $M USD  ......  Subscribe
G&A costs $M USD 275
Total OpEx $M USD  ......  Subscribe
Income Taxes $M USD  ......  Subscribe
Gross revenue (LOM) $M USD  ......  Subscribe
Net revenue (LOM) $M USD  ......  Subscribe
EBITDA (LOM) $M USD  ......  Subscribe
Pre-tax Cash Flow (LOM) $M USD  ......  Subscribe
After-tax Cash Flow (LOM) $M USD  ......  Subscribe
Pre-tax NPV @ 10% $M USD  ......  Subscribe
After-tax NPV @ 5% $M USD  ......  Subscribe
After-tax NPV @ 10% $M USD  ......  Subscribe

Heavy Mobile Equipment

Fleet data has not been reported.


Mine Management

Job TitleNameProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required Sep 2, 2023
....................... Subscription required ....................... Subscription required Subscription required Sep 2, 2023

Aerial view:


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