Brazil

Surubim Mine

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Overview

Mine TypeOpen Pit
Commodities
  • Copper
Mining Method
  • Truck & Shovel / Loader
Production Start... Lock
Mine Life2034
ShapshotThe Surubim Mine re-started operations in 2022.
Related AssetCaraíba (MCSA) Operation

Owners

SourceSource
CompanyInterestOwnership
Ero Copper Corp. 99.6 % Indirect
Mineração Caraíba S.A. (operator) 100 % Direct
Ero Copper Corp. is a Vancouver-based copper mining company whose primary asset is a 99.6% interest in Mineração Caraíba S.A. (“Mineração Caraíba” or “MCSA”).

MCSA holds a 100% interest in each of the Caraíba Operations.

Deposit type

  • Metamorphic hosted
  • Vein / narrow vein
  • Intrusion related

Summary:

The Surubim District, containing the Surubim OP Mine (including planned production from underground), located at 9°34’12” S and 39°51’52” W, also includes the C-12 OP/UG Mine, located at 9°34’44” S and 39°52’27” W, the Lagoa da Mina project, located at 9°30’13” S and 39°47’48” W adjacent to the past producing Angicos Mine, the Cercado Velho project, located at 9°30’36” S and 39°47’52” W and the Terra do Sal project, located at 9°38’1” S and 39°49’6” W.

The Surubim District is located in the central part of the Curaçá Valley. The C12 deposit is located 1.2 km to the SW of the Surubim Mine. The Cercado Velho and Lagoa da Mina deposits are approximately 10 km to the NE of the Surubim Mine whereas the Terra do Sal deposit is situated 8 km to the SE of Surubim Mine. The Surubim Mine and C12 Deposits are hosted in the Surubim gneiss (alternating tonalitic and granorioditic bands with gabbro and diorite bands) whereas the other three deposits of the Surubim District are hosted in the Caraíba gneissic complex (biotite orthogneiss with local migmatite). The geology of the Surubim Mine and C12 deposit consists of large gabbro-dominant units with minor pyroxenite units and remnants of gneiss that are at least 400m wide. In both deposits, the mafic-ultramafic units are intruded by late north-striking granite and pegmatite dykes. The geology of the Cercado Velho, Lagoa da Mina and Terra do Sal consist of orthogneiss and migmatites intruded by ultramafic units measuring a few centimeters up to 15m thick.

In all the deposits of the Surubim District, the mafic-ultramafic lithological units are generally northerly oriented, and they dip steeply to moderately the west (Figure 7-28, A, B). Two main systems of easterly dipping anastomosing faults occur at the Surubim mine and are oriented NNE-SSW and NNW-SSE respectively. The movements along those faults, and their importance to the copper mineralization, are not well documented.

The mafic-ultramafic intrusive rocks and the gneiss were subjected to variable alteration, including phlogopite, silica, chlorite, K-feldspar, epidote, serpentine, and carbonate. Moderate to intense phlogopite alteration is characteristic of the Surubim deposit whereas k-feldspar, diopside and silica alteration zones are dominant in the Cercado Velho and Lagoa da Mina deposits.

The copper mineralization of the Surubim Mine and C12 deposit occurs as lenses that are hosted by phlogopite-altered gabbro injected by pyroxenite dykes to form what is designated as the ultramafic complex. Sulphide minerals are chiefly chalcopyrite and bornite in a ratio of 4:1 that mainly occur as disseminations and veins. Chalcocite, covellite and cubanite also occur as minor sulphides associated with the mineralization surrounding the Surubim Mine. Magnetite and minor pyrite and pyrrhotite are also associated with the mineralization with pyrrhotite being an important sulphide at the Lagoa da Mina and Cercado Velho deposits. The Terra do Sal deposit is characterized by disseminated and veinlets of pyrrhotite, chalcopyrite with minor bornite, pyrite and pentlandite. Specifically:

- At Surubim, the Cu mineralization is hosted in a series of moderately NW-dipping, NNW-SSE striking lenses measuring a few meters up to 45 m thick. Mineralization is known over 300 m in the N-S direction and 100 m E-W and extends to 400 m below surface. The mineralization remains open at depth and to the NNE extension.

- At C12, the Cu mineralization occurs as several interpreted N-S striking lenses measuring a few meters and up to 75 m thick. However, the general trend of the higher-grade Cu mineralization extends for over 170 m to the NW, approximately 50 m in the NE-SW direction, and is known to a depth of 300 m below surface. The mineralization remains open along the NW and NE extensions and at depth.

- The Cu mineralization at Lagoa da Mina corresponds to a series of steep westerly-dipping, northerly-striking lenses associated with melanorite and pyroxenite and measuring from 10 to 50 m thick and up to 110 m long. The deposit covers an area of 200 m N-S by 80 m E-W and is know to a depth of 430 m. The Cu mineralization remains open in its NW-SE strike extensions and at depth.

- At Cercado Velho, the Cu mineralization is hosted in a series of northerly-trending lenses associated with gabbro and norite and measuring from 5 to 30 m thick by up to 110 m long. The deposit covers an area of 455 m N-S by 200 m wide and is known to a depth of 220 m. The Cu mineralization remains open to the north, the south, and at depth.

- The Cu mineralization at Terra do Sal is hosted in several northerly-trending lenses associated with pyroxenite and gabbro and varying between 10 and 50 m thick and reaching up to 120 m in length. The deposit covers an area of 180 m N-S by 130 m in its E-W extension and is known to a depth of 380 m. The
Cu mineralization remains open in all directions except to the west.

Reserves

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Mining Methods

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Comminution

Crushers and Mills

Milling equipment has not been reported.

Summary:

Ore is transported from the Vermelhos UG Mine and the Surubim Mine to the Caraíba Mill complex via the Curaça Valley Haul Road, which passes adjacent to the Surubim Mine in the central portion of the Curaçá Valley, over a total transport distance of approximately 80 kilometers.

Caraíba Mill
The stockpile feeds two primary double deck screens, configured with 100mm aperture on the top and 40mm aperture on the bottom decks. The material over 40mm feeds one of two secondary cone crushers (seven-feet (“ft.”) standard Symons; 1,400t/h of capacity each) set to 28mm aperture. Screen undersize and secondary crushers products discharge onto one conveyor in an open circuit configuration.

Secondary cone crusher discharge and primary screen fines are blended with tertiary crusher discharge and are conveyed to the seven secondary double screen decks, configured with 25mm aperture on the top and 16mm aperture on the bottom decks. Tertiary crushing is performed with four standard CH660 Sandvik cone crushers (capacity of 350t/h each) set to 20mm aperture. Oversize material passes to the tertiary crushers operating in a closed-circuit configuration. Final product from the combined crushing and screening operations is 88% passing 1/2”.

Crushed ore is conveyed to the stacker-reclaimer system to further homogenize the ore for feeding the plant. The stacker-reclaimer system is comprised of a two-armed stacker and a 16 bucket-wheel reclaimer with capacities of 1,600t/h and 1,200t/h, respectively. Crushed ore capacity of the stacker-reclaim system is currently 140,000 tonnes.

GRINDING
The grinding circuit consists of two identical lines operating with a primary ball mill operating in closed circuit with a dedicated battery of 26” hydro-cyclones. Each ball mill is 5.0 m by 7.6 m, charged with 90 mm in diameter high chrome cast steel balls. The nominal grinding capacity of each mill is 200 t/h each. Typical ball consumption is 340 g/t.

Blended ore from the stacker reclaimer is withdrawn through belt feeders below one of the 3,000 tonne ore silos that are interconnected. Ore is delivered to the ball mill over a belt weightometer to control and measure the mass of ore sent to each mill for metallurgical accounting purposes.

The coarse fraction from the cyclone underflow recycles to the ball mill feed chute for further grinding. Overflow from both grinding lines combines as feed to the high frequency screeners and regrinding circuit.

HIGH FREQUENCY SCREENS AND REGRINDING CIRCUIT
The cyclone oversize is pumped to high frequency screening operations comprised of eight screens with five decks each of 105+ micron aperture. The high frequency screening coarse fraction is gravity fed to the vertical mill (STM HIG Mill HIG2300/23000) for regrinding, operating in an open circuit. The HIG Mill (High Intensity Grinding mill) was commission in September 2020. The screening operation fines combine with the regrind mill product and are pumped to the flotation.

Processing

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Production

Combined production numbers are reported under Caraíba (MCSA) Operation

Operational metrics

Metrics202320192018
Tonnes processed 000000
Total tonnes mined 0000004,096,723 t
Daily ore mining rate
Ore tonnes mined
^ Guidance / Forecast.

Production Costs

Commodity production costs have not been reported.

Operating Costs

Currency2021201920182017
OP mining costs ($/t mined) BRL 10.5  11.7  15.4  12.7  

Heavy Mobile Equipment

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Personnel

Mine Management

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Aerial view:

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