The Tucano Mine is located in Amapá State, Brazil, approximately 200 km from Macapá, the state capital, and is accessible via the Brazilian federal highway BR-210.
The Tucano Mine tenement portfolio is comprised of 197,283 ha, 100% controlled by Great Panther. This large land package in one of the most interesting areas in the world for gold exploration covers approximately a 90 kilometres long section of the Vila Nova Greenstone Belt, centered around the Tucano Mining License.
The mine site is relatively remote but counts with existing infrastructure such as road access, hydro power, telecommunications and the port at Santana. The towns of Serra do Navio and Pedra Branca do Amapari are the nearby communities where 90% of the workforce comes from. The Santana port can accommodate relatively large ships as it was built for bulk material handling and has been in use until recently to handle iron ore from the Zamin property, adjacent to the Tucano Gold Mine site, to the southeast.
The Tucano Gold Mine is a well-established mining operation comprising eight open pits, the Urucum North underground project, a processing plant and tailings dam. Mine production to date has been sourced from all deposits except Urucum East.
Mine production within the presently developed LOM pits is the responsibility of a mining contractor, U&M Mineração e Construção S.A. (“U&M”), and utilizes conventional earthmoving equipment with drill and blast, load and haul operations. The mined ore is blasted in 8-metre benches and dug in two 4-metre cuts with backhoe excavators loading ore and waste into off-highway dump trucks. Mined ore is either fed directly to the crusher or temporarily stockpiled.
The existing processing plant was designed by Ausenco. After approximately four years of operation, an expansion was planned, also by Ausenco, as part of the original Definitive Feasibility Study to install a 3 MW ball mill. This new secondary grinding mill, alongside the 7 MW single stage SAG mill, was installed in order to maintain 3.1 million tonnes per annum throughput capacity treating 100% of the much harder sulphide ore type.
A new oxygen plant was installed at site in 2019 to deal with sulfide material and through that additional step, recoveries of sulfide ores can reach higher than 90% recoveries.
|Tonnes waste moved (t)||18,173,428||20,357,867||23,562,964|
|Gold ore mined (t)||2,440,542||2,266,881||1,858,037|
|Gold ore milled (t)||3,504,129||3,074,014||3,359,041|
|Head grade (g/t)||1.25||1.37||1.28|
|Plant recovery (%)||87.3%||91.7%||90.8%|
|Total gold recovered (oz)||123,296||123,867||125,417|
|Total gold sold (oz)||122,472||106,000||125,176|
|Cash costs (US$/oz)||$880||$1,118||849|
|All-in sustaining costs (US$/oz)||$1,073||$1,406||$1,200|
- Tucano operating and financial results from 2015 through to 2018 were reported by the previous owner, Beadell Resources Limited
- Tucano operating results for 2019 are a composition of Beadell operating data for the period January 1 to March 4, and Great Panther operating data for the period March 5 to December 31.
- Tucano cost data for 2019 is reflective of the Great Panther results for the period March 5 to December 31.
Tucano is hosted by the Proterozoic aged Vila Nova Greenstone Belt, with many similarities to the greenstones in West Africa that contain many world-class deposits, and to which the Guyana Shield was once connected. Tucano belongs to the sub-category of Iron Formation Hosted Gold Deposits, which includes notable names such as the historic Homestake Mine in South Dakota and the Musselwhite Mine in northern Ontario.
Tucano’s exploration package comprises 39 tenements covering an area of 1,972 square kilometres. These tenements are at various stages of advancement from application for exploration license to exploration license, and applications for mining licenses, through to mining concessions. There is a pipeline of high potential near-mine prospects, anchored by several high-grade gold drill intervals over several metres, which will be fast-tracked as near-term opportunities to increase resources and prolong the mine life. In 2020, Great Panther undertook a detailed evaluation of the available regional geophysical and geochemical data and developed a litho-structural model allowing the definition of high potential exploration corridors and targets within the large exploration tenement portfolio. In 2021 Great Panther initiated efficient regional exploration programs over these high potential corridors and is fast-tracking exploration of prioritized targets.
Highlights of resource conversion in 2020 drilling, in particular at Tapereba (“TAP AB”) on the southern part of the mine sequence were reported on June 23, 2020, and a new Mineral Resource and Mineral Reserve estimate, on December 15, 2020. Highlight intercepts from TAP AB are presented below. These results demonstrate the presence of higher-grade mineralization within the mine sequence and the need to understand the controls on, and the grade and continuity variations, in these zones. In 2021, drilling will focus on resource replacement and expansion for the open pit operations, in particular at TAP C and deeper drilling to delineate and test variability and continuity of high-grade zones for inclusion in underground mining studies.
TAP C is a series of three pits over a 1,500 m trend of which the C1 pit is the largest with a depth of 50 m and a strike length of approximately 700 m. Initial results of drilling reported on April 7, 2021, and re-modelling of the TAP C1 deposit define the structural framework that has affected the mineralization. The updated model being used to guide ongoing drilling, explains mineralization discontinuities while providing better controls on areas of pinch and swell of the mineralized zones. The pit was mined by the previous operator down to the base of the oxide zone. The Tucano plant now has the capability to process both oxide and sulphide ore.
Exploration in the tenement package, which is around 90 km long by an average of 20 km wide, includes over 500 km of regional multi-element soil sampling complimented by auger and rotary air blast drilling. Once environmental permitting is in place targets will be tested by Reverse Circulation drilling. 2021 initiated with activities on the Mutum and Saraminda targets that are being evaluated for fast-tracking.
Highlights from near-mine drilling at the TAP AB1 and AB3 open pits
|Drill hole||Interval (m)||From (m)||To (m)||Est. true width (m)||Grade (g/t Au)|
- DD = diamond drilling; RC = reverse circulation
- Highlight drill results are +25 gram*metre intervals intersected in drilling this year.
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Reserve & Resource Estimates
Mineralization at Tucano is controlled by a major north-south shear zone. The texture and mineralogy along the shear zone indicate high-temperature hydrothermal alteration. This zone exhibits intense hydrothermal alteration, particularly silicification and sulfidation, bearing auriferous pyrrhotite and pyrite. The alteration is most intense in the proximity of reactive meta-sediments such as banded iron formations and carbonate and, to a lesser extent, in calcsilicates, schists, and amphibolites. Late cross cutting intrusions are typically barren.
The mineralization at Tucano occurs in a series of deposits over a 7 km strike length associated with the north-south trending shear zone occurring coincident with a north-south line of topographic ridges. From south to north, these deposits have been named TAP AB, TAP C and Urucum. Duckhead is a high-grade open pit to the southeast of the TAP deposits. Higher grades are associated with the more intensely hydrothermally altered rocks.
|Tonnes (000s)||Grade Au g/t||Contained Au oz|
- Mineral Reserves were classified using the Canadian Institute of Mining, Metallurgy, and Petroleum Definition Standards for Mineral Resources and Mineral Reserves 2014 (CIM Definition Standards).
- Mineral Reserve estimation includes mine depletion through to September 30, 2020, and drills results through to July 31, 2020. The effective date of the Mineral Reserve estimate is September 30, 2020.
- Open pit Mineral Reserves are estimated within designed pits above discard cut-off grades that vary from 0.43 g/t Au to 0.5, g/t Au for oxide ore and 0.58 g/t Au to 0.63 g/t Au for fresh ore. The cut-off grades are based on a gold price of US$1,500/oz Au and operating costs sourced from the current operations and mining contracts at an US$/Brazilian exchange rate of 1:4.5.
- Mineral Reserves incorporate estimates of dilution and mineral losses.
- Underground Mineral Reserves were estimated using an incremental cut-off grade of 2.4 g/t Au. The cut-off grades are based on a gold price of US$1,250/oz Au and operating costs sourced from the operations and mining contracts at an US$/Brazilian exchange rate of 1:3.8.
- A minimum mining width of 20 metres was used for open pit Mineral Reserves and three metres was used for underground Mineral Reserves.
- The Mineral Reserve estimate includes surface stockpiles.
- Average metallurgical process recovery is 91.5%.
- Numbers may not add due to rounding.
TUCANO MINERAL RESOURCE ESTIMATES AT SEPTEMBER 30, 2020
|Tonnes (000s)||Grade Au g/t||Contained Au oz|
- Mineral Resources were classified using CIM Definition Standards.
- Mineral Resources are inclusive of Mineral Reserves.
- The effective date of the Mineral Resource estimate is September 30, 2020.
- Mineral Resources are estimated at various cut-off grades depending on mining method and mineralization style.
- For open pit development at Urucum, Urucum East and TAP AB, Mineral Resource estimates use a long-term gold price of US$1,750/oz and a US$/Brazilian real exchange rate of 1:4.5 with cutoff grades of 0.3 g/t Au for oxide and 0.4 g/t Au for fresh rock.
- Underground Mineral Resource estimates for TAP AB use a long-term gold price of US$1,750/oz and a US$/Brazilian real exchange rate of 1:4.5, with cutoff grade of 1.3g/t Au for fresh rock.
- Since September 30, 2019, no additional drilling data is available for the Urucum underground and Duckhead so Mineral Resource estimates for 2020 remain unchanged from 2019. Estimates use a long-term gold price of US$1,500/oz and a US$/Brazilian real exchange rate of 1:3.8 with cutoff grades of 0.4 g/t Au for oxide and 0.55 g/t Au for fresh rock in the open pit and 2.1 g/t Au for oxide and 1.6 g/t Au for fresh for the underground.
- A minimum mining width of 3 metres was used for preparation of mineralization wireframes.
- Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability.
- Inferred Mineral Resources have a great amount of uncertainty as to their existence and as to whether they can be mined legally or economically. It cannot be assumed that all or part of the Inferred Mineral Resources will ever be upgraded to a higher category.
- Numbers may not add due to rounding.
Great Panther’s own technical qualified persons oversaw the process and carried out new estimates on the Urucum and Urucum East open pit deposits. SLR Consulting Ltd. (previously RPA) prepared and acted as independent technical qualified persons for the TAP AB deposit.
On behalf of Great Panther, Neil Hepworth, Chartered Engineer MIMMM supervised the preparation of and approved for inclusion herein, the Tucano Mineral Reserve estimates and Nicholas Winer, Fellow AusIMM and Carlos Pires, Chartered Professional, Member AusIMM (CP) supervised the preparation of and approved for inclusion herein, of the Tucano Mineral Resource estimates (other than TAP AB open pit and underground Mineral Resource estimate). Messrs. Hepworth, Winer and Pires are non-independent Qualified Persons as defined by NI 43-101.
On behalf of SLR Consulting Ltd., Reno Pressacco, P. Geo., and Tudorel Ciuculescu P. Geo. supervised the preparation of and approved for inclusion herein, the TAP AB Mineral Resource estimate. Messrs. Pressacco and Ciuculescu are independent Qualified Persons as defined by National Instrument 43-101.
The Qualified Persons for Mineral Resource and Mineral Reserve estimation have reviewed the Tucano QA/QC program. The QA/QC program for drill core includes the regular insertion of blanks, standards, and duplicates into sample batches, diligent monitoring of assay results, and necessary remedial actions. Resource drilling samples are first assayed at the Tucano onsite laboratory. All intervals with anomalous gold are submitted and re-analyzed by the Certified, SGS Geosol laboratory in Belo Horizonte by 50 g fire-assay. All SGS Geosol assays, after diligent monitoring of QA/QC and necessary remedial actions, supersede the Tucano assay results in the database for MRMR grade estimation. QA/QC monitoring of the SGS laboratory also includes inter-laboratory checks on five percent of samples with the Certified, ALS laboratory in Belo Horizonte. In addition to the data verification methodology described above, personal inspections of the Tucano property have also been completed.
Unless stated otherwise, all scientific and technical information contained herein has been reviewed and approved by Neil Hepworth, Chartered Engineer MIMM, Chief Operating Officer, Fernando A. Cornejo, P. Eng., Vice-President, Operations, Brazil and Nicholas Winer, Vice-President, Exploration of Great Panther, each a Qualified Person as defined by NI 43-101.
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NI 43-101 Technical Report on the Tucano Gold Mine
Amapa, Brazil | September 30, 2020