Mining Intelligence and News
Brazil

Pilar Mine

Click for more information

Categories

Overview

Mine TypeUnderground
StatusActive
Commodities
  • Gold
Mining Method
  • Sub-level open stoping (SLOS)
  • Mechanized Cut & Fill
Backfill type ... Lock
Production Start... Lock
Mine Life... Lock
SnapshotOre produced from Pilar is transported to the Caeté processing plant adjacent to Roça Grande, a total distance of approximately 40 km by road.

During 2023, the Pilar mine replaced its underground haulage fleet with fixed-frame trucks that can travel up the ramps more quickly, for improved trucking efficiency and shorter cycle times.

2023 was a challenging year operationally as Pilar mine encountered geometry changes in primary orebodies, leading to dilution and extraction problems.
Related AssetCaete Complex

Owners

SourceSource
CompanyInterestOwnership
Jaguar Mining Inc. 100 % Indirect
Mineração Serras do Oeste Ltda. (operator) 100 % Direct
The Caeté Mining Complex is owned and operated by Jaguar’s wholly-owned subsidiary, Mineracão Serras do Oeste (MSOL).

Contractors

Lock

- subscription is required.

Deposit type

  • Banded iron formation hosted
  • Vein / narrow vein

Summary:

The Pilar and Roça Grande deposits are examples of the Algoma BIF hosted type, Córrego Brandão is a folded and sheared deposit hosted in carbonate-quartz-chlorite schists with iron occurrences.

Mineralization style:
The mineralization consists of predominately “lateral” replacements/sulphidations of the iron carbonate-rich bands of the host Algoma type BIF units. The BIF hosted gold mineralization at Pilar, however, is not syngenetic in nature (in relation to the deposition of the host rock packages), rather it is clearly an epigenetic event that has occurred after the formation of the host rock units. There is a clear temporal-spatial-genetic relationship between the replacement/sulphidation of the host BIFs and the onset of a structurally controlled, district scale silicification event at Pilar. Textural observations suggest that at least two episodes of quartz veining has occurred. The early stage veining is deformed by the regional strain and clearly pre-dates the deformation event. The later stage veins are observed to crosscut the strain-related fabrics and so are interpreted to represent a younger mineralizing event that has taken place some time after the regional deformation event.

- Dimensions of the economic orebodies: Economic strike lengths of only 50 m to 350 m for individual mined zones. The average thicknesses of the BIF hosted orebodies may range from two metres to 20 m.

PROPERTY GEOLOGY
The Pilar deposit is hosted by the basal units of the Nova Lima Group, and by sequences of the QuebraOssos Group. The rock packages in the immediate Pilar area are comprised of tholeiitic metabasalts, mica-quartz schists, chlorite-quartz schists, quartz-chlorite-sericite schists, and volcano-chemical and clastic meta-sedimentary rocks of the Santa Quitéria Unit (Nova Lima Group), and further to the east, of meta-komatiite flows (along with their intrusive equivalents) of the Quebra- Ossos Group. The volcanochemical meta-sedimentary rock packages include cherts, BIFs, and carbonaceous phyllites. Along the eastern edge of the Pilar property, the supracrustal units of the Rio das Velhas Supergroup are in fault contact with migmatites and granitic gneisses of the Santa Bárbara Complex, the unit that locally represents the basement sequence.

Pilar occurs at the northernmost end of the northeasterly oriented Brumal-Pilar BIF trend, which extends for many kilometresto the southwest from the Pilar deposit. In regional terms, the Brumal-Pilar BIF linear trend corresponds to a package of “Algoma type” BIFs (oxide-facies, silicate-facies, and carbonate-facies lithotypes) that represent the main economic target as hosts of the Pilar deposit.

Past regional mapping demonstrated that the Brumal BIF trend within the Pilar site is folded into a considerably tight, overturned synform-antiform fold of approximately one kilometre in amplitude, with axes statistically plunging steeply to the southeast and with an axial-planar tectonic cleavage dipping steeply in the east-southeast direction.

While the “Algoma type” BIFs typically range between five metres and 15 m to 20 m in thickness, at Pilar, they have been severely and tightly folded and thickened as a result of a west-verging compressional regional deformation event that affected the entire eastern border of the Rio da Velhas Supergroup exposures in the Iron Quadrangle Terrain. Structural geometries recorded at Pilar indicate that the mine stratigraphic package may have been folded and refolded during this event. Moreover, some major reverse faults and/or accommodation faults (such as faulted synform closures) formed during this regional compressional event locally exhibit evidence of the presence of later superimposed events (mainly tilting and/or rotation of the previously faulted blocks).

Stratigraphically, the Pilar BIF Unit is overlain by a two to five metre thick layer of carbonaceous phyllites, which in turn is overlain by a thick package of greenschists (meta-basic volcanic rocks - “Upper Basic Volcanic Unit”). The Pilar BIF Unit is underlain by a thick package of greenschists (“Lower Basic Volcanic Unit”). The Lower and Upper basic volcanic units are very similar in nature, if not identical, considering their lithologies, lithostratigraphic record, and penetrative structural petrofabrics mapped.

MINERALIZATION
Geological mapping and underground observations indicate that mineralized zones of the Pilar BIF Unit represent generally stratabound lenses of “sulphide-facies” BIF ranging from 15-20 m to 100-200 m in strike length and two metres to 15 m in thickness. In the Pilar deposit, the best grade BIF hosted mineralized zones are typically located along the contact between the Pilar BIF Unit and the layer of carbonaceous phyllites that occurs immediately adjacent to the greenschists of the Upper Basic Volcanic Unit. Moreover, at the Pilar deposit, increased average gold grades and higher sulphide/arsenopyrite concentrations (within the economic mineralized zones and orebodies) are almost everywhere mapped in association with the deposit scale, larger, higher-amplitude fold hinge geometries. The BIF hosted mineralized zones are conformably folded together with the whole Pilar BIF Unit at the deposit scale “synclinorium” of the Pilar deposit.

Economic gold mineralization at Pilar is hosted by the folded, and locally refolded, Pilar BIF Unit including the SW Limb, São Jorge, BF III, BF II, BF, LPA, and BA mineralized zones, and by the conformably folded Torre meta-volcanic sequence.

The main zones of mineralization occur as scattered, stratabound lenses of sulphide-facies BIFs within the “carbonatic-oxide-facies” deposit scale Pilar BIF Unit. Economic mineralized bodies consist of stratabound, but not stratiform, concentrations of gold bearing sulphides that occur in scattered grains, seams, and irregular shaped granular aggregates located along and replacing iron carbonates-rich bands of the BIFs. Arsenopyrite and pyrrhotite are the most important sulphide minerals in mineralized bodies, with pyrite, chalcopyrite, galena, and sphalerite commonly present as accessory minerals. A direct relationship can generally be established between the amounts of arsenopyrite (percentage per volume) and the gold concentrations in mineralized BIF samples of the Pilar deposit.

Individual quartz veins are typically less than one metre in width and can be observed to be of three generations. Quartz veins of the first generation are typically associated with the gold mineralization and are folded by the main tectonic event which affected the Pilar package as a whole. Quartz veins of the second generation are typically lower grade or barren and are not affected by folding. Lastly, quartz veining of the third generation is associated with the aforementioned extensional tectonic cleavage and may also be related to halos of mineralization/sulphidation where related to hinge structural domains.

At the Pilar deposit, increased average gold grades and higher sulphide/arsenopyrite concentrations (within the economic mineralized zones and orebodies) are almost everywhere (or at least very frequently) mapped in association with the deposit scale, larger, higher-amplitude fold hinge geometries. Increased average gold grades and higher sulphide/arsenopyrite concentrations have also been observed in association with a second folding event (and/or with a subsequent third folding event) in the Pilar BIF package (Tiago Souza, 2020). The second folding event would have brought mineralized quartz veins into the BIF Pilar package, however, according to Tiago Souza (2020), the third folding event was responsible for the generation of the economic mineralization hosted by the large fold hinge geometries of the Pilar package (São Jorge synform, BF II antiform, BF antiform, BF II-BF Junction synform, BA antiform, and the smaller-amplitude Torre antiforms).

Reserves

Lock

- subscription is required.

Mining Methods

Lock

- subscription is required.

Comminution

Crushers and Mills

Milling equipment has not been reported.

Processing

Lock

- subscription is required.

Production

CommodityUnits202320222021202020192018201720162015
Gold oz  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe40,68340,91834,01727,84629,242
All production numbers are expressed as metal in doré.

Operational metrics

Metrics202320222021202020192018201720162015
Ore tonnes mined  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe
Tonnes processed  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe433,000 t365,082 t338,000 t290,000 t309,000 t
Daily ore mining rate  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe1,100 t1,100 t1,000 t1,000 t1,000 t

Production Costs

CommodityUnits2023202220212020201920182017
Cash costs (sold) Gold USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 811 / oz   702 / oz   937 / oz  
All-in sustaining costs (sold) Gold USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 1,119 / oz   986 / oz   1,226 / oz  

Financials

Units2023202220212020201920182017
Sustaining costs M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 12.4   11.5   9.8  
Capital expenditures M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 13.5   11.8   11.2  
Revenue M USD 53.2   52   42.4  

Heavy Mobile Equipment

Lock

- subscription is required.

Personnel

Mine Management

Job TitleNamePhoneEmailProfileRef. Date
....................... Subscription required ....................... Subscription required ........... Subscription required ........... Subscription required Subscription required Jul 16, 2024
....................... Subscription required ....................... Subscription required Subscription required Dec 31, 2021
....................... Subscription required ....................... Subscription required Subscription required Dec 31, 2021
....................... Subscription required ....................... Subscription required Subscription required Jul 16, 2024
....................... Subscription required ....................... Subscription required Subscription required Jul 16, 2024
....................... Subscription required ....................... Subscription required Subscription required Jul 16, 2024
....................... Subscription required ....................... Subscription required Subscription required Jul 16, 2024
....................... Subscription required ....................... Subscription required Subscription required Jul 16, 2024

EmployeesContractorsTotal WorkforceYear
...... Subscription required ...... Subscription required ...... Subscription required 2021

Aerial view:

Lock

- subscription is required.