Overview
Stage | Production |
Mine Type | Open Pit |
Commodities |
|
Mining Method |
|
Processing |
- Smelting
- Gravity separation
- Carbon re-activation kiln
- Concentrate leach
- Agitated tank (VAT) leaching
- Carbon in leach (CIL)
- Elution
- Carbon adsorption-desorption-recovery (ADR)
- Solvent Extraction & Electrowinning
- Cyanide (reagent)
|
Mine Life | 2.5 years (as of Jan 1, 2018) |
The drilling resulted in increasing the Life of Mine (LOM) for the Lavrinha open pit deposit. |
Source:
p. 47
Aura has contracted the Brazilian company Dinex to mine the Lavrinha open pit Deposit. The major equipment in the fleet is specified as Volvo excavators, CAT dozers, Scania trucks and Sandvik drills. The contract term is 24 months, and is to be done by contract phase, with Phase I at 450kt/month to the end of April, 2017, and Phase II at 750kt/month to the end of mine life.
Summary:
The Lavrinha Deposit which is closely linked to the Ernesto Deposit has been interpreted as gold-rich quartz veins and veinlets with coarse grained pyrite occurring along shallow-dipping structure. The main difference with Ernesto is the position of the mineralization in the metasedimentary sequence. Gold mineralization is located along quartz boudins in highly sericitized rock and plunges to the north.
The Ernesto-Lavrinha Deposits consists of gold- rich quartz veins and veinlets occurring along a relatively thick, shallow-dipping structure at the base of the metasedimentary sequence and within altered sulphidic horizons in overlying meta- arenite units. The basal structure is interpreted to be a low-angle detachment fault that has been folded and faulted together with the overlying stratigraphy. Gold mineralization is located along asymmetrical anticlines and synclines that plunge gently to the north and are cut by NW and NE- trending narrow faults. The gold mineralization occurs in three zones: Lower Trap, Middle Trap and Upper Trap.
The Upper Trap, which is widely developed in the Lavrinha Deposit, occurs in metapelitic rocks (hematite sericite schist) in dilation zones of the intensely deformed synclinal troughs. The Upper and Intermediate traps share similar alteration and mineralization suites.
The Ernesto-Lavrinha Deposits are described as detachment-style gold deposits, where typically gold mineralization is associated with low-angle to flat detachment faults, generally with a normal (extensional) sense of movement which consistently places younger units over older units.
Summary:
Approximately 1.11 Mt of ore at an average grade of 1.69 g/t Au and 14.0 Mt of waste rock will be mined from the Lavrinha open pit over a 2.5 year period. The overall strip ratio for Lavrinha is 12.6:1 with mining conducted 365 days per year by a contractor. The contract is full service and includes providing all mining equipment, drilling, blasting, loading, hauling and maintenance. Total material movement rates for the LOM range from 15,000 to 25,000 tpd.
Conventional truck and hydraulic shovels will be utilized. Four excavators, supported by three front-end loaders, will load a fleet of ten 38- tonne trucks and five 25-tonne trucks. Ore will be transported to the primary crusher and run-of-mine (“ROM”) pad, and waste material will be hauled to a nearby waste rock storage facility.
Lavrinha open-pit mine is a part of the Ernesto/Pau-a-Pique complex located in the southwest of Mato Grosso state, near Pontes e Lacerda in Brazil which consists of the following gold deposits: the Lavrinha open-pit mine (“Lavrinha”), the Ernesto open-pit mine (“Ernesto”), the Pau-a-Pique underground mine (“Pau-a-Pique” or “PPQ”), the Japones open-pit mine, the Nosde open-pit mine, and the near mine open-pit prospects of Bananal North and Banal South. The Lavrinha Property is contiguous to Ernesto and does not contain any infrastructure.
The Lavrinha open pit mining operation is fully contracted. Conventional truck and hydraulic shovels will be utilized. Four excavators, supported by three front-end loaders, will load a fleet of ten 38-tonne trucks and five 25-tonne trucks. Ore will be transported to the primary crusher and run-of-mine (“ROM”) pad, and waste material will be hauled to a nearby waste rock storage facility.
Approximately 1.11 Mt of ore at an average grade of 1.69 g/t Au and 14.0 Mt of waste rock will be mined from the Lavrinha open pit over a 2.5 year period. The overall strip ratio for Lavrinha is 12.6:1 with mining conducted 365 days per year by a contractor. The contract is full service and includes providing all mining equipment, drilling, blasting, loading, hauling and maintenance. Total material movement rates for the LOM range from 15,000 to 25,000 tpd
Flow Sheet:
Processing
- Smelting
- Gravity separation
- Carbon re-activation kiln
- Concentrate leach
- Agitated tank (VAT) leaching
- Carbon in leach (CIL)
- Elution
- Carbon adsorption-desorption-recovery (ADR)
- Solvent Extraction & Electrowinning
- Cyanide (reagent)
Flow Sheet:
Summary:
Ore from Lavrinha Open Pit will be hauled on a road to the Ernesto processing plant.
The EPP gold processing plant is located next to the Ernesto Deposit and is designed to treat up to 1 Mtpy feed. The flowsheet is based on a low-risk proven technological configuration for processing gold bearing ore.
A primary crusher located at the front-end of the process plant. Run-of-mine (“ROM”) feed will be blended and fed through the plant’s primary screen. The screen oversize is crushed and the combined crushed feed is ground in a single-stage, closed-circuit semi-autogenous grinding (“SAG”) mill.
Approximately 25% of the SAG mill cyclone underflow feeds a gravity-gold recovery circuit. The grinding circuit product is thickened and then pumped to a leach tank that is followed by six carbon-in-leach (“CIL”) tanks in series. CIL tailings are treated in a cyanide reduction tank where cyanide is chemically decomposed. Final tailings are pumped to a tailings storage ........

Recoveries & Grades:
Commodity | Parameter | 2018 | 2017 |
Gold
|
Recovery Rate, %
| 94.7 | 93.5 |
Gold
|
Head Grade, g/t
| 1.13 | 1.15 |
Production:
Commodity | Units | 2018 | 2017 |
Gold
|
oz
| 40,071 | 35,305 |
All production numbers are expressed as metal in doré.
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Operational Metrics:
Metrics | 2018 | 2017 |
Total tonnes mined
| 10,347,517 t | 7,951,056 t |
Ore tonnes mined
| 1,238,537 t | 1,234,667 t |
Waste
| 9,108,980 t | 6,716,389 t |
Stripping / waste ratio
| 7.35 | 5.44 |
Tonnes processed
| 1,166,750 t | 1,018,479 t |
Reserves at December 31, 2020:
The Mineral Resource estimates based on an optimized pit shell using US$1,900/oz gold and at a cut-off grade of 0.40 g/t Au.
Mineral Reserves for were estimated at a cut-off grade of 0.40 g/t Au and applying 40 % dilution factor with 98% mining recovery.
Category | Tonnage | Commodity | Grade | Contained Metal |
Proven
|
80,670 t
|
Gold
|
1.84 g/t
|
4,785 oz
|
Probable
|
804,880 t
|
Gold
|
0.9 g/t
|
23,300 oz
|
Proven & Probable
|
885,550 t
|
Gold
|
0.99 g/t
|
28,085 oz
|
Measured
|
61,980 t
|
Gold
|
2.59 g/t
|
5,170 oz
|
Indicated
|
636,214 t
|
Gold
|
1.24 g/t
|
25,420 oz
|
Measured & Indicated
|
698,194 t
|
Gold
|
1.36 g/t
|
30,590 oz
|
Commodity Production Costs:
| Commodity | Units | 2018 | 2017 |
Cash costs
|
Gold
|
USD
|
824 / oz
|
778 / oz
|
Corporate Filings & Presentations:
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Aerial view:
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