Borborema Gold


The Borborema Gold project is located in the Seridó area of the Borborema province, within the State of Rio Grande do Norte in north eastern Brazil. Borborema consists of three mining leases covering a total area of 29 km² plus freehold title to the property over the main prospect area.

Borborema is considered a technically low risk operation in terms of resource definition, mining operation and metallurgical processing and is fully permitted in terms of have all environmental, mining and installation licences required to commence operations.The Project also has strong community and Government support at both the local and State level and the Company is encouraged to fast-track development.

Due to the prioritisation of economic projects by the region, the Project enjoys strong local and Governmental support and significant tax concessions are provided for the operation.

Exploration tenements covering a total 410km2 extend along trend of the Borborema mining leases and remain prospective for adding resources to the Borborema inventory in the near future.

A Definitive Feasibility Study was completed in December 2019 for Stage 1 development of Borborema and updated in July 2020. This initial operation plans to produce 730,000oz gold  at an AISC of US$713 per ounce gold with the project returning an estimated NPV8% of US$342M.

View to the south over Borborema project site showing gold mineralisation exposed in the pit and proximity of infrastructure. Transmission line to the left of the pit links with main power grid crossing the Borborema leases.


Leases are enhanced by good on-site facilities and efficient logistics and power infrastructure (such as a water permit, a sealed highway directly from the project area to the city and port of Natal) with 230kv power lines adjacent and in close proximity. Borborema is approximately 20km from the mining town of Currais Novos providing access to an experienced labour force along with local engineering and construction capacity, significantly reducing project development and execution risk.

Project Details

The Borborema project is mineable as an open pit potentially to 300 metres below surface at least. The operation will be staged to maximise returns and Stage 1 will have an initial 10 year mine life before expansion.

The ore body is consistently 30m – 35m thick and up to 50m, remains open in all directions and appears to have a high grade plunging gold shoot developing to the south. The resources and reserves have been clearly defined and the project significantly de-risked through the 104,500m of drilling which highlights a continuous and consistent single ore body, approximately 3.5km long with a higher-grade core that can be optimised in the mine plan.

Borborema has a 2.43Moz JORC Code (2012) compliant Mineral Resource estimate and a 42.4Mt Ore Reserve containing 1.61Moz gold at 1.18 g/t Au.  The planned Stage 1 development schedules to mine less than half the current reserve to produce 730,000 oz gold.   .

There are no metallurgical issues with the ore and metallurgical testwork indicates gold recoveries of at 92.6% with short residence times and low reagent consumption through a conventional CIL circuit.

Definitive Feasibility Study

A Definitive Feasibility Study (DFS) for development and construction of Stage 1 of the Borborema Project was completed in December 2019, (refer ASX Announcement of 23 December, 2019). It confirmed the project’s strong economics and optimised a profitable open pit with a mine life of more than 10 years producing approximately 729,000 ounces gold.

During March – June 2020, the DFS was further reviewed and optimised and made changes which further derisked the planned operation and saw significant improvements to the required capital expenditure (US$91M) and operating costs with an AISC of US$713 per ounce – placing Borborema in the first quartile of mine operating costs. Refer to the ASX announcement of 9 July, 2020 for further details.

Assuming a gold price of US$1,550 per ounce, the pre-tax NPV (8%) returned US$342M with an IRR of 64.7%.  Post tax that is estimated to be US$287M and 57.9% respectively. The project returns an average EBITDA of US$72M pa. The estimated project capital cost is US$79.5M plus contingency of US$11.3M totalling U$90.7M.

Stage 1 mining schedules less than half of the original Mineral Reserve and Resource which will be targeted for later stages of operation. No inferred category Mineral Resources were included in the Stage 1 mine schedule.

Borborema Gold Project

Definitive Feasibility Study at Gold Price US$1,550

Stage 1 Reserve scheduled in DFS

20 Mt at 1.22g/t Au (784,480 oz)

Mine Life

10.2 years

Gold produced (oz):         LOM

729,734 oz

Years 1- 5

410,700 oz

C1 Cash cost per oz


AISC (per oz Au)


Capex (incl Contingency)


NPV (8%) Post Tax




Gross Revenue (LOM)


Average EBITDA per year


(refer ASX Announcements of 23 December, 2019 and 9 July, 2020)

The project’s measured, indicated and inferred Mineral Resource Estimate of 2.43Moz @ 1.10 g/t gold, remains open in all directions (refer to ASX Announcement of 24 July 2017).

Borborema Gold Project
Mineral Resource by Multiple Indicator Kriging (MIK) estimation



(g/t Au)

Contained Gold (Moz)









Total Measured + Indicated








Total Mineral Resources




Table 1. Mineral Resource (JORC 2012) table, reported above 0.5 g/t Au cut-off.  Parent Block 25mE x 25mN x 5mRL.  Selective Mining Unit 5mE x 6.25mN x 2.5mRL. Note, appropriate rounding has been applied, subtotals may not equal total figures. (refer ASX Announcement of 24 July 2017).



The information provided on this site is of a general nature only. Although it has been prepared in good faith with all due care there can be no guarantee that it will continue to be accurate in the future. No one should act or rely upon the information but should undertake their own independent due diligence or seek appropriate professional advice. To the extent permitted by law Big River Gold Limited (“Big River”) excludes all liability from any statement in, or omission from, this report. Nothing in this report should be construed as either an offer to sell or a solicitation of an offer to buy or sell Big River securities in any jurisdiction.

You are missing some Flash content that should appear here! Perhaps your browser cannot display it, or maybe it did not initialize correctly.