Overview
Stage | Production |
Mine Type | Underground |
Commodities |
|
Mining Method |
- Mechanized Cut & Fill
- Sub-level stoping
- Backfill
|
Processing |
- Gravity separation
- Filter press plant
- ACACIA reactor
- Centrifugal concentrator
- Carbon re-activation kiln
- Flotation
- Concentrate leach
- Agitated tank (VAT) leaching
- Carbon in pulp (CIP)
- Elution
- Carbon adsorption-desorption-recovery (ADR)
- Solvent Extraction & Electrowinning
- Cyanide (reagent)
|
Mine Life | 5 years (as of Jan 1, 2021) |
Latest News | Jaguar Mining Reports Updated Mineral Reserves and Mineral Resources for the Pilar Mine,Brazil as at May 31, 2020 August 18, 2020 |
Source:
p. 4
Company | Interest | Ownership |
Jaguar Mining Inc.
|
100 %
|
Indirect
|
Mineração Serras do Oeste Ltda.
(operator)
|
100 %
|
Direct
|
The Caeté Mining Complex is operated by Jaguar’s wholly-owned subsidiary, Mineracão Serras do Oeste (MSOL).
Deposit Type
- Banded iron formation hosted
- Vein / narrow vein
Summary:
The Pilar and Roça Grande deposits are examples of the Algoma BIF-hosted type. The main geological characteristics of this group are summarized as follows:
- Main host/fertile “Algoma-type” BIF Units: These units host the mineralization and are stratigraphically located at the waning stages of major volcanic cycles of the Rio da Velhas greenstone belt.
- Mineralization style: The mineralization consists of mainly “lateral” replacements/sulphidations of the iron carbonate-rich bands of the host Algoma-type BIF units. However, the BIF-hosted gold mineralization 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.
- Dimensions of the economic orebodies: Economic strike-lengths of only 50 m to 350 m for individual mined zones. Average thicknesses of the BIF-hosted orebodies may range from 2 m to 20 m.
The Pilar deposit is hosted by the basal units of the Nova Lima Group, and by sequences of the Quebra-Ossos Group. The rock packages in the immediate area of the mine are comprised of tholeiitic meta-basalts, mica-quartz schists, chlorite-quartz schists, quartzchlorite-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.
Within the current footprint of the Pilar Mine, there are only two known zones of mineralization that outcrop at surface and which were previously mined in an open pit operation; South-West (SW) and São Jorge Synform. The currently mined BF and BF II zones are truly “blind” mineralized zones that occur at deeper levels of the Pilar deposit and were discovered and put into production by Jaguar only after the initial years of the underground operation.
The Pilar Mine occurs at the northernmost end of the northeasterly oriented Brumal-Pilar BIF trend. The Brumal BIF trend extends for many kilometres to the southwest from the Pilar deposit. In regional terms, the Brumal-Pilar BIF linear trend corresponds to a package of “Algoma-type” BIFs.
Regional mapping showed that the Brumal BIF trend within the Pilar mine 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.
The “Algoma-type” BIFs typically range between five metres and 15 m to 20 m in thickness, however, within the Pilar property, 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 the Pilar Mine indicate that the mine stratigraphic package may have been folded and re-folded during this event.
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”).
Geological mapping and underground observations show that mineralized bodies of the Pilar BIF Unit represent scattered, generally stratabound lenses of “sulphide-facies” BIF ranging from 15-20 m to 100-200 m in strike-length and two metres to 10-15 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. The BIF-hosted mineralized bodies are conformably folded together with the whole Pilar BIF Unit at the deposit-scale “synclinorium” of the Pilar deposit (São Jorge Synform, BF II Antiform, Junction Synform, BF Antiform, BA Antiform).
MINERALIZATION
The economic gold mineralization at the Pilar Mine is hosted by the folded, and locally re-folded, Pilar BIF Unit including the SW, São Jorge, BF III, BF II, BF, LPA, and BA mineralized zones, and by the conformably folded Eastern Torre meta-volcanic sequence. The main zones of mineralization occur as scattered, stratabound lenses (or “pods”) 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, in seams, and in irregular-shaped granular aggregates located along and replacing iron carbonates-rich bands of the BIFs.
Individual quartz veins are typically less than one metre in width and can be observed to be of three generations. The 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 mine package as a whole. The quartz veins of the second generation are typically lower grade or barren and are not affected by folding. Lastly, the quartz veining of the third generation is associated to the above-mentioned extensional tectonic cleavage and may also be related to halos of mineralization/sulphidation where related to hinge structural domains.
Mining Methods
- Mechanized Cut & Fill
- Sub-level stoping
- Backfill
Summary:
There are two mining methods in use. The current LOMP forecasts longhole mining with delayed backfill for the majority of the Mineral Reserves. Mechanical cut and fill mining is used when ore geometry does not favour longhole mining.
Ventilation for the Pilar Mine is a pull system. Air is drawn down through the ramp and up an exhaust rise near the ramp. Ventilation on the levels uses auxiliary fans and vent ducting. Water is pumped to the surface using submersible pumps, pumped from level to level, then to the surface.
The Pilar Mine is accessed from a five metre by five metre primary decline located in the footwall of the deposit. The portal is located at an elevation of 760 MASL. The Pilar Mine is divided into levels with Level 01 established at elevation 690 MASL. All ore is hauled to the surface via the ramp using both contractors and company personnel. From this point, the level spacing is 75 m vertical, i.e., Level 02 is at elevation 615 MASL, Level 03 at elevation 540 MASL, etc. A three- metre-thick sill pillar is left between levels. Sublevels are excavated from the main ramp at 20 m vertical intervals to provide intermediate access to the mining panels. At each level and sublevel, drifts are developed near the centre of the mineralized zone to expose the footwall and to hang wall contacts. The drift is extended in both directions along strike, under geological control for alignment, continuing to expose the contacts until the limits of the deposit are reached. This provides for two working faces per sublevel.
Production at the Pilar Mine is predominantly achieved by the longhole mining method, which is carried out on a longitudinal retreat sequence towards the central access. Stopes are up 50 m in length are separated by three metre to five-metre-wide pillars, depending on the thickness of the zone. In order to reduce external dilution, five metre high by five-metre-long pillars are strategically left in the stope when there are adjacent stopes in parallel. The stope is then drilled from the lower drift underneath the pillar. When the mining of each longhole stope has been completed, the excavation is filled using development waste. Development waste volume is well matched to the backfill volume needed. There are times when development waste rock is either hauled to the surface or hauled from the surface to an underground stope being filled due to timing. The mine has the potential to use hydraulically placed cemented classified flotation tailings backfilling. Mining then proceeds upward to the next sublevel, and the sequence is repeated until the sill pillar is reached. Stopes are mined from several sublevels simultaneously in order to provide the required number of active workplaces needed to meet production targets.
The Pilar Mine is highly mechanized. Development and mining activities are accomplished with a fleet of two twoboom and two one-boom electric-hydraulic jumbos. Longhole drilling is completed with three Sandvik production drills. Four 10t Sandvik LH410 LHD units are used for mucking. A fleet of seven Volvo A30 articulated trucks are used to haul the broken rock to the surface. Contractors are used to supplement development and haulage, as well, and the fleet is adjusted to meet the demand.
Ground conditions were observed by RPA/SRL Consultants to be good. The main decline, portions of which were developed up to ten to fifteen years ago, did not exhibit any roof or wall deterioration. Primary support in the Pilar Mine is provided by using split sets, grouted rebar and, in the wider areas, grouted cable bolts. Two single-boom electric-hydraulic jumbos are used for rock bolting.
The addition of ground control engineers to Jaguar’s workforce has resulted in improved quality of backfill and overall ground support at the mines. As mentioned previously, changes to the stope designs with strategic pillars have reduced dilution and increased stability. Regular ground support maintenance (QA/QC testing) has been implemented at the mines on the main infrastructure. Maintenance includes bolt testing, proper cable bolt designs, and empirical stope design analysis.
Flow Sheet:
Crusher / Mill Type | Model | Size | Power | Quantity |
Gyratory crusher
|
.......................
|
|
111 kW
|
1
|
Cone crusher
|
.......................
|
|
223 kW
|
2
|
Ball mill
|
|
5.0m x 6.0m
|
2240 kW
|
1
|
Summary:
CRUSHING
The ore from the Pilar and Roça Grande mines is transported by trucks to the crushing circuit and placed in the ROM stockpile. The crushing circuit is made up of a CJ411 - 111 kW primary jaw crusher in open circuit, and secondary (CH440-223 kW) and tertiary (CH440 223 kW) cone crushers operating in closed circuit.
The ROM stockpile ore is fed to the jaw crusher with a front end loader though a grizzly and vibrating feeder. The jaw crusher discharge feeds a multi deck screen (3,500 mm x 1,800 mm – with three panel decks consisting of apertures of 75 mm, 35 mm, and 16 mm respectively top to bottom), the undersize of each deck feeds secondary crushing, tertiary crushing, or the final product conveyor respectively. The secondary cone crusher operates in closed circuit with a double deck screen (5,700 mm x 2,400 mm – with two panel decks consisting of 35 mm and 16 mm apertures). Product from the double deck screen either recirculates back to the secondary crusher, feeds the tertiary crusher, or goes to the final product conveyor. The tertiary cone crusher operates in closed circuit with a single deck screen (3,500 mm x 1,800 mm – with a panel deck aperture of 16 mm), with the oversize recycling to the crusher and undersize product going to the final product conveyor, which discharges onto the crushed ore stockpile. The final particle top size of the crushing process is 16 mm.
GRINDING
The grinding circuit consists of a 2240 kW ball mill (5 m x 6 m EGL) with a capacity of up to 100 tonnes per hour, operating in closed circuit with a series of hydrocyclones. The overflow from the hydrocyclones (-200 mesh or -74 µm) proceeds to the flotation circuit, and the underflow (+200 mesh or +74 µm) either feeds the gravity concentration circuit (75%) or is recycled to the ball mill feed (25%).
Processing
- Gravity separation
- Filter press plant
- ACACIA reactor
- Centrifugal concentrator
- Carbon re-activation kiln
- Flotation
- Concentrate leach
- Agitated tank (VAT) leaching
- Carbon in pulp (CIP)
- Elution
- Carbon adsorption-desorption-recovery (ADR)
- Solvent Extraction & Electrowinning
- Cyanide (reagent)
Flow Sheet:
Summary:
The Caeté processing plant has a design capacity of 720,000 tpa of ROM ore. The process flowsheet consists primarily of the following unit operations:
- Crushing;
- Grinding;
- Gravity Gold Recovery;
- Flotation;
- Leaching and CIP;
- Gold Recovery;
- Detoxification;
- Tailings Disposal.
GRAVITY GOLD RECOVERY
Gravity concentration uses a Knelson centrifugal gravity concentrator to recover fine particles of free gold. The gravity concentrate proceeds to an Acacia intensive cyanidation reactor (Acacia), from which the gold bearing solution is pumped directly to a dedicated set of electrolytic cells. The precipitate from the cells is processed into doré bars in the refinery
FLOTATION
The flotation circuit consists of a series of twelve 14.1 m3 (500 ft3) flotation cells, the first three operating as roughers, three operating as primary scavengers, three operating as secondary scavengers, and the last three operating as ........

Recoveries & Grades:
Commodity | Parameter | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 |
Gold
|
Recovery Rate, %
| ......  | ......  | ......  | 88.8 | 90.2 | 90.6 | |
Gold
|
Head Grade, g/t
| ......  | ......  | ......  | 3.92 | 3.46 | 3.3 | 3.27 |
Production:
Commodity | Units | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 |
Gold
|
oz
| ......  | ......  | ......  | 40,918 | 34,017 | 27,846 | 29,242 |
All production numbers are expressed as metal in doré.
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Operational Metrics:
Metrics | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 |
Tonnes processed
| ......  | ......  | 433,000 t | 365,082 t | 338,000 t | 290,000 t |
Daily ore mining rate
| ......  | ......  | 1,100 t | 1,100 t | 1,000 t | 1,000 t |
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Reserves at December 31, 2021:
Mineral Resources at Pilar were estimated at a cut-off grade of 1.66 g/t Au.
Mineral Reserves at Pilar were estimated at a cut-off grade of 2.11 g/t Au.
Category | Tonnage | Commodity | Grade | Contained Metal |
Proven
|
1,221 kt
|
Gold
|
3.8 g/t
|
149 koz
|
Probable
|
887 kt
|
Gold
|
3.6 g/t
|
102 koz
|
Proven & Probable
|
2,108 kt
|
Gold
|
3.71 g/t
|
251 koz
|
Measured
|
2,338 kt
|
Gold
|
3.91 g/t
|
294 koz
|
Indicated
|
1,499 kt
|
Gold
|
3.6 g/t
|
173 koz
|
Measured & Indicated
|
3,837 kt
|
Gold
|
3.79 g/t
|
467 koz
|
Inferred
|
2,125 kt
|
Gold
|
4.21 g/t
|
288 koz
|
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