Big River Gold : Water Studies Provide Process Security

ASX RELEASE

2 December 2021

Figure 2. Borborema site layout and water management features (from: "Site-wide water

balance for the Borborema Project", SRK (Oct 2021))

1 A 1% Annual Exceedance Probability (AEP) event.

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Seven scenarios and three sub-scenarios were evaluated in SRK's study with details of each provided in Appendix 1 attached to this announcement.

Incorporated into these were the possible water savings to be obtained by employing evaporation control methods of which the most common technique uses floating covers. In Brazil, using PET plastic bottles as floating covers has reduced evaporation by up to 72% with 80% of the dam area covered.

These scenarios established that the most effective way of reducing any site process water deficit (in order of impact) were:

1. Delivery of sewage water from Currais Novos;
2. Implementation of evaporation reduction methods, and
3. Enlargement of the Fines Dyke storage capacity.

Early decommissioning of the Sao Francisco dam would increase storage to the Fines Dyke, reduce overall evaporation and may also lead to increased water flow without increase in the height of the Fines Dyke dam wall.

Water sourced from borefields in the district would also improve site water management and this potential is being investigated.

Those scenarios with the lowest estimated water deficits are summarised in Table 1.

• Scenarios E1 and E2 required less greywater inflow than the baseline scenarios to assure the supply of the water demand even in dry years. Scenario E1 required less sewage compared to scenario E2.
• Scenario F which employed a combination of water management actions (refer Appendix 1) did not need to include the greywater to supply the demand.

Table 1. Comparison of the sewage inflow required from Currais

Novos for each scenario

1. This column refers to the Raw Water dam demand on the STP Borborema
2. This column refers to the average sewage inflow from Currais Novos (note that this value depends on the availability of the stochastic generated sewage)

Currais Novos sewage water facility

Since assuming management and refurbishment of the assigned sewage pump station, BRV has been progressively repairing and refurbishing the sewage boxes and system, reaching flow rates of 51.5 m3/hr. BRV will continue to improve the existing infrastructure and plans to add additional pumps and surge tanks

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as we work toward achieving the 70m3/hr flow for which we have agreed with the local water authority,

CAERN.

In seeking increased water flow and security the Company is negotiating with CAERN to assume more responsibility for the system while working to increase the water allocation assigned to Borborema. We are also investigating identified bore fields to the north and south which may hold the potential to provide significant water flows with gravity feed to site as an additional risk mitigation.

The results of the SRK study are significant for the Project and BRV.

The Company is confident of not requiring additional water supply from Currais Novos in most years to meet a 2Mtpa production profile. Furthermore, the water flows currently being obtained at Currais Novos not only further de-risk the Project but also identify a water source that could support production expansion up to 4Mtpa.

For and on behalf of the Board.

Andrew Richards

Executive Chairman

Big River Gold Ltd

About Big River Gold

Big River Gold Ltd (ASX:BRV), is a mineral exploration and development company listed on the Australian Securities Exchange. Its major focus is the 2.43M ounce Borborema Gold Project in Brazil; a country the Company believes is underexplored and offers high potential for the discovery of world class mineral deposits.

Borborema Gold Project

Borborema is a project with a resource of 2.43Moz gold, located in the Seridó area of the Borborema province in north-eastern Brazil. It is 100% owned by Big River and consists of three mining leases covering a total area of 29 km2 including freehold title over the main prospect area.

The Project benefits from a favourable taxation regime, existing on-site facilities and excellent infrastructure such as buildings, grid power, water and sealed roads. It is close to major cities and regional centres and the services they can provide.

Competent Person Statements

Borborema mineral resource estimate

The information in this announcement that relates to the mineral resource estimate for the Borborema Project was first reported in accordance with ASX Listing Rule 5.8 on 24 July 2017. Big River confirms that it is not aware of any new information or data that materially affects the information included in the announcement of 24 July 2017 and that all material assumptions and technical parameters underpinning the Mineral Resource estimate continue to apply and have not materially changed.

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