The Tocantinzinho Gold Project is an advanced-stage open pit gold deposit being developed in the State of Pará, Brazil.
Containing 2 million ounces (MOZ) of reserves, the mine is owned 100% by G Mining Ventures (GMIN) through its wholly owned subsidiary Brazauro Recursos Minerais (BRM).
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The key permits to start construction and installation licence were received in 2017. The mining concession was issued in 2018.
The detailed engineering commenced in the first quarter (Q1) of 2022 and completed in Q3 of 2023.
Initially, a Feasibility Study (FS) of the mine was completed in 2015, followed by an updated technical report in 2019. The owner published an updated FS in February 2022.
As per the 2022 FS, the project has an average annual gold production of 174,700oz at an All-In-Sustaining Cost (AISC) of $681/oz. The FS outlines 1.8MOZ of total gold production over 10.5-year mine life.
The mine construction started in Quarter (Q3) of 2022 and has been completed. The project received hot commissioning permit in June 2024 from the Pará State Environmental Agency, SEMAS.
The operational licences for commercial operations of the project was received by GMIN from the Pará State Environmental Agency, Secretaria de Estado de Meio Ambiente e Sustentabilidade (SEMAS), in August 2024.
The project completed its first gold pour in July 2024, yielding approximately 440oz of gold. It was followed by first exports of doré bars from the mine to a refinery in Switzerland in August 2024.
The doré bars were sold in excess of $2,400/oz. Tocantinzinho is on budget and time to start operations in the second half (H2) of 2024.
Tocantinzinho Location
Tocantinzinho is located approximately 200km south-southwest of the Itaituba city, 1,150km southwest of Belém (Pará’s capital), and 108km from the Morais de Almeida district.
The mine is in the Tapajós Gold Province along the north seacoast of Brazil at the mouth of the Amazon River.
The 996km2 land package is accessible by a 72km municipal road. The road connects the mine to the Transgarimpeira state road or highway.
The highway is located 50km south of the property and connects the BR-163 Federal Highway in Morais Almeida. The highway crosses Jardim do Ouro and crosses approximately 22km east of the Jamanxim River barge.
An existing 108km dirt road connects the mine to BR-163. A total of 14.8km of service roads will connect the various infrastructures of the project.
A 775m Pista Nações Unidas airstrip is situated 2km south of the camp at the mine site. A 1,300m long airstrip is planned for the project.
Ownership History
The historical mining was related primarily to gold mineralisation in the Tapajós Gold Province. Small-scale mining was conducted by artisanal miners in the 1950s, discovering gold.
The historical production by primitive artisanal mining methods amounted to between 200,000 and 1Moz of gold annually.
It was estimated at approximately 16Moz of gold by the 1990s. The extraction of gold commenced in 1970 in the Tocantinzinho area followed by an intense small-scale mining activity in mid-1980s to mid-1990s.
In 1979, the Agência Nacional de Mineração (ANM), previously the Departamento Nacional de Produção Mineral (DNPM), granted an exploration licence to Mineração Aurífera over the Tocantinzinho area.
The exploration licence expired in 1986. The DNPM archived the property files in 1992.
In 1997, a joint venture was formed by Renison Goldfields and Altoro for gold exploration in Brazil. The joint venture explored mine area under Altoro (operator).
The joint venture was terminated in 1998 and the projects and data were acquired by Altoro.
Solitario Resources acquired Altoro in 2000. Due to a drop in gold price, the Tocantinzinho Project was terminated in 2001.
The land over the project mineralisation was acquired by Brazauro Resources through its Brazilian subsidiary Jaguar Resources do Brazil in 2003.
In July 2008, an acquisition agreement was signed between Eldorado Gold and Brazauro for continued exploration and development of the project.
Eldorado acquired the Brazauro in July 2010 by acquiring Brazauro’s issued and outstanding securities for approximately CAD 122.4m ($90.80m).
Between 2012 and 2018, Eldorado increased the project tenement from 33,979 ha to 68,803.6 ha.
Through the acquisition of issued and outstanding shares of Brazauro Recursos Minerais, GMIN acquired the project from Eldorado in October 2021 for $115m.
Geology and Mineralisation
Tocantinzinho is situated beneath the igneous rocks of older magmatic arcs of the Tapajós (CuiúCuiú/Creporizão).
The host granitic rocks at the project intrude as elongated bodies along a northwest-striking fault zone. The zone cut through extensive quartz monzonites and granites.
The host granitic intrusions represent volatile-rich late components of the parent magma.
The mineralisation of the project consists of gold associated with pyrite, granites, quartz, alkali feldspar, plagioclase, alkali feldspar granite consisting of quartz, K-feldspar, and albite.
Tocantinzinho Mineral Resource Estimate
At gold cut-off grade of 0.30 grams per tonne (g/t), the measured mineral resources estimate of the mine is 17.60 million tonnes (Mt) containing 841koz of gold at a grading of 1.49g/t.
The indicated mineral resource estimate is 29.07Mt containing 1,211koz of gold at a grading of 1.30g/t.
The total (measured + indicated) mineral resource estimate of the mine is 46.68Mt containing 2,052koz of gold at a grading of 1.37g/t.
The inferred mineral resource estimate is 7.91Mt containing 23koz of gold at a grading of 0.90g/t.
At gold cut-off grade of 0.36g/t, the proven mineral reserves at Tocantinzinho are 17.97Mt containing 842koz of gold at a grading of 1.46G/t.
The probable mineral reserves are 30.70Mt containing 1,200koz of gold at a grading of 1.22G/t.
The total (proven + probable) mineral reserves of the project are 48.67Mt containing 2,042koz of gold at a grading of 1.31G/t.
Mining and Processing Methods
Tocantinzinho will use conventional open pit mining techniques with 10m benches. An owner mined open pit operation is planned for the mine.
The operation will use hydraulic shovels, mining trucks, and blasting. The mining will be conducted in three main phases. The phases will be preceded by a starter pit.
The open pit will generate 48.7Mt of ore (including historic tailings) over the Life of Mine (LOM) for 3.36:1 average LOM strip ratio and 163.4Mt of waste rock.
The mining is planned for 11-year period. It includes two years of pre-production mining. The mill schedule comprises two months of commissioning with ore.
The commercial production will be achieved with 10.5 years of operation after the second month-planned to achieve 60% of nameplate throughput.
The nominal throughput is 12,890 tonnes per day (t/d) or 4,705 kilo tonnes (kt) per year peak milling capacity for the first 7.5 years. The process plant will have a nominal throughput of 4.34Mt/y of granite ore.
The Run-of-Mine (ROM) will be crushed in a primary circuit of the process plant. The coarse ore will be stockpiled and reclaimed from the coarse ore stockpile and reclamation circuit. The material will be grinded in a Semi-Autogenous Grinding (SAG) mill.
The grinded material will enter a ball mill with hydro cyclones, producing P80 of 125µm final product.
The final product will undergo gravity concentration in a gravity concentration circuit, producing a gold-rich concentrate.
The gold-rich concentrate will be leached intensively, subsequently recovering gold through electrowinning.
With an average mass pull of 4.5%, the two-stage flotation circuit will produce sulphide concentrate. The concentrate will undergo pre-leach, cyanide leaching, and carbon adsorption for 36 hours in a Carbon-In Leach (CIL) circuit.
The carbon will be eluted via a 3 tonne (t) pressure zadra circuit and then handled and regenerated. The electrowinning and smelting will produce gold doré bars.
During H-2 of July 2024, the process plant feed reached a peak of 10kt/d with 4,232oz of gold production at an average gold recovery of 85.1%.
Currently, the focus is on ramping up of the process plant to nameplate plant capacity of 4.7Mt/y expected for full production and target recoveries.
Project Infrastructure
Tocantinzinho infrastructure will consist of access roads, a process and a sewage plant and support buildings, mine haul roads, mine site, mine support infrastructure, administration and general infrastructure, camp facilities, and tailings and water management.
The infrastructure will support the operation of a 25Mt/y (27.5Mt/y at peak) open pit mine.
The process plant and support buildings will comprise a 500m2 mill office and a 1,300m2 reagent storage building.
The mine site will have 4.2km mine haul roads connecting the open pit area to the dumps, leach ponds, process plant, an open pit, two waste storage facilities, and mine support facilities.
The mine support infrastructure will include a 475m2 temporary maintenance facility, a 815m2 warehouse, five heavy duty bays, a permanent maintenance facility, a 420 kilo litre (KL) capacity fuel storage tank, and a wash bay.
A 160t explosive storage facility and a 784me assay laboratory will be a part of the mine support infrastructure.
A 1,700m2 administration complex, telecom towers, a recycling and sorting facility, a greenhouse, and a 200m2 nursery will be the key components of the administration and general infrastructure.
The existing 100-bed temporary camp will be expanded to a 200-bed camp and a 1,200-person capacity permanent camp facility will have three types of camp modules during construction.
During operations, the permanent camp will service approximately 800 persons.
Up to 200m3/h of raw water will be supplied for operations by a vertical pumping station in Veados Creek.
Power Supply and Distribution
Tocantinzinho will be powered by a new 193km/138kV transmission line connecting the Equatorial Energia Pará, the National Grid substation at Novo Progresso, to the site substation near the process plant.
Equatorial Energia Pará will operate the power line. The transmission line includes 483 towers and upgrades to the exit bay at Novo Progresso. The line construction was completed in December 2023, followed by its commissioning in January 2024.
The power will be distributed to the mine by a substation. The substation will step down power from the transmission line to 13.8kV by two 20/25MVA 138-13.8kV transformers.
Each transformer will have the capacity to power the entire mine site. A 13.8kV switchgear lineup will be powered by each transformer.
For larger loads, the power will be stepped further down to either 4.16kV or 3kV. The remaining power will be transformed to 480V. Single-phase loads like lighting will be powered at 220/380V.
Two overhead lines will deliver power to the facilities outside the main mine site. The north line will power the sewage plant, intake pumps, CIL Ponds 1 and 2, and raw water intake pumps.
The south line will power the exploration camp, the flotation tailings pond, the main gatehouse, the landfill, and the explosives area.
The backup power will be delivered by emergency diesel generators located near the process plant.
Contractor Involved
The 2022 FS of Tocantinzinho was prepared by G Mining Services with the support of Lincoln Metallurgical, CGM Expert, SRK Consulting, and F&Z Consultoria e Projetos.
