Mining Intelligence and News
Spain

OroValle/El Valle Operation

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Overview

Mine TypeUnderground
StatusActive
Commodities
  • Gold
  • Silver
  • Copper
Mining Method
  • Drift & Fill
  • Longitudinal stoping
  • Transverse stoping
  • Sub-level stoping
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SnapshotEl Valle Boinás and Carlés mines and the El Valle processing plant, collectively El Valle, producer of copper concentrate and doré.

The Boinás underground mine is producing asset. The Carlés open pit and underground mines are currently on care and maintenance. Underground mining at Carlés is planned to re-commence in the near future with pre-development and mine development activities scheduled for 2024.

The Orovalle has changed its underground hauling strategy starting January 1, 2023. From this date onwards, all hauling is being carried out using trucks. The shaft is on care and maintenance.
Related Asset

Owners

SourceSource
CompanyInterestOwnership
Orvana Minerals Corp. 100 % Indirect
OroValle Minerals S.L. (operator) 100 % Direct
Through its wholly-owned subsidiary, Orovalle Minerals S.L., Orvana Minerals Corp. owns and operates the El Valle and Carlés mines.

Deposit type

  • Skarn
  • Breccia pipe / Stockwork

Summary:

Gold-copper skarns have developed mainly along the contact between intrusives and carbonate units. Two different types of skarn have been recognised at El Valle-Boinás. The first is a calcic skarn related to limestone units and the second is a magnesian skarn, called “black skarn”, that is related to dolomite units.

The gold-copper bearing skarns at Carlés are generally calcic skarns. Better grade goldcopper mineralisation is associated with high magnetite and bornite content that is localised in generally continuous, relatively thin (four metres thick) layers of retrograde skarn.

At the El Valle-Boinás deposit, reactivation of fracture zones (along northeast-southwest, eastwest, and northwestsoutheast orientations) produced widespread brecciation and favoured the emplacement of porphyritic dykes. A low temperature alteration and mineralisation event is spatially and genetically associated with the subvolcanic porphyry dykes, which overprint all previous lithologies. Depending on the host rock, there are different styles of hydrothermal alteration and mineralisation, such as: sericite-adularia-carbonates (+py-aspy) in granites and skarns; leaching, enrichment, and silicification in skarns (+ native copper and chalcocite); and silicification (+py) in dolomites.

Highest gold grades occur where the low temperature mineralisation overprints previously mineralised gold-copper skarn, forming jasperoid or semi-jasperoids with native copper and minor chalcocite and cuprite. The associated geochemistry is characterised by an increase in As, Sb, and Hg. This low temperature event is the principal gold mineralising episode at El Valle.

Gold, and in some cases base metal mineralisation, has been found in association with late tectonic breccias related to low angle thrust faults at El Valle-Boinás. The origin of the gold mineralisation in these structures is thought to be due to remobilisation of previous skarn or jasperoid related gold mineralisation. Gold associated with low angle structures is important at El Valle-Boinás where a significant percentage of the open pit minable gold mineralisation extracted from the Boinás East Zone came from this type of structure.

EL VALLE-BOINÁS
Mineralisation at the El Valle-Boinás copper-gold deposit can be grouped into several significant deposits related to the Boinás granitic intrusive and carbonate rocks of the Láncara Formation (Cambrian age).

The gold mineralisation system has a strike length of two kilometres and a width of at least 0.5 km. The intrusive is elongated trending N35°E with a length of 500 m and an average thickness of 300 m. A copper-gold mesothermal skarn was developed mainly along the contact between the igneous rock and the carbonate unit.

Late reactivation of the main northeast trending fracture system was accompanied by two or more phases of epithermal mineralisation as well as the intrusion of porphyry dykes. These events produced hypogene oxidation with further enrichment of gold, arsenic, antimony, and mercury (Martin-Izard et al., 1999). Rhyodacite dykes, which are always sericitised, were emplaced along fractures and breccia zones trending north-northeast. The intense silicification along fractures and breccia zones resulted in the formation of hematitic jasperoid that is characterised by enrichment in gold, arsenic, antimony, and mercury. The presence of cuprite and native copper in the structures and breccias suggests the leaching of chalcocite, which is encountered at a depth of approximately 400 m along the A107 structure. This can be viewed as evidence of two-cycle leaching and enrichment.

CARLÉS
The Carlés deposit is a gold and copper bearing skarn developed predominantly in the Devonian limestones of the lower portion of the Rañeces Formation along the north margin of the Carlés granodiorite. The Carlés intrusion is approximately circular in plan with a diameter of approximately 750 m. The intrusion is located at the intersection of major faults (east-west, northeast-southwest, and southeast-northwest) and it is bisected from west to east by the Río Narcea. The northern part of the granodiorite is in contact with the lower part of Rañeces Formation and the southern part of the intrusion is in contact with the siliciclastic Furada Formation. Several barren Permian porphyritic and diabasic dykes crosscut the existing lithologies.

Mineralisation is continuous for over 1,000 m, ranging in thickness from 1.5 m to over 25 m, dipping 50° to 90° away from the granitic intrusion. The skarn is known over a vertical continuity of 400 m and remains open at depth.

The Carlés skarn is of calcic composition and is an exoskarn although irregular endoskarn has developed locally. It consists of layers of garnet (grossularite-andradite composition) intercalated with layers of pyroxene skarn, mostly of hedenbergite composition. Retrograde phases of the skarn results in the formation of irregular magnetite layers associated with amphibole. Inside these bands is where most of the copper sulphides and gold mineralisation occur. The skarn mineralisation transitions into coarse grained marbles then non-altered limestones away from the intrusive. The latter may show narrow intercalations of distal garnetpyroxene incipient skarn.

Gold mineralisation at Carlés is closely associated with copper sulphides, which consist of disseminated and patchy chalcopyrite and bornite that precipitated mainly in the magnetite zone. Other minerals common in the skarn are arsenopyrite, löellingite, pyrrhotite, and latestage pyrite. Mineralisation at Carlés is divided into four areas: Carlés East, Carlés North, Carlés Northwest, and Carlés West.

Reserves

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Mining Methods

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Comminution

Crushers and Mills

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Processing

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Production

CommodityProductUnits2024202320222021202020192018201720162015
Gold Metal in conc./ doré oz  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe64,32758,25951,54644,68253,733
Copper Metal in concentrate k lbs  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe5,0155,1235,5064,2576,128
Silver Metal in conc./ doré oz  ....  Subscribe  ....  Subscribe  ....  Subscribe182,635144,411166,744
Gold Equivalent Metal in conc./ doré oz  ....  Subscribe  ....  Subscribe
^ Guidance / Forecast.

Operational metrics

Metrics202320222021202020192018201720162015
Daily ore mining rate  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe
Daily milling rate  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe1,898 dmt1,830 dmt2,040 dmt1,235 dmt1,401 dmt
Hourly processing capacity  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe
Annual milling capacity  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe750,000 t750,000 t
Ore tonnes mined  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe713,818 wmt647,852 wmt733,086 wmt479,077 wmt551,966 wmt
Tonnes milled  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe658,046 dmt623,137 dmt707,362 dmt452,003 dmt511,213 dmt
Daily processing capacity  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe2,000 dmt2,000 dmt2,000 dmt2,000 dmt

Production Costs

CommodityUnits20242023202220212020201920182017
Cash costs (sold) Gold USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 1,004 / oz **   1,129 / oz **   1,293 / oz **  
All-in sustaining costs (sold) Gold USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 1,185 / oz **   1,331 / oz **   1,574 / oz **  
All-in costs Gold USD  ....  Subscribe  ....  Subscribe  ....  Subscribe 1,190 / oz **   1,331 / oz **   1,574 / oz **  
^ Guidance / Forecast.
** Net of By-Product.

Financials

Units20242023202220212020201920182017
Capital expenditures (planned) M USD  ....  Subscribe
Capital expenditures M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 8.7   6.5   9.7  
Revenue M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 90.3   80.2   71.6  
Pre-tax Income M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 2.2   -9.4   -20.9  

Heavy Mobile Equipment

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Personnel

Mine Management

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EmployeesContractorsTotal WorkforceYear
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Aerial view:

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