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B2Gold has announced a substantial increase in the mineral resource estimate for its Fekola mine as well as positive results from its ongoing Fekola mill expansion study.

Mali - The new increased mineral resource and the positive results, to date, from the Fekola mill expansion study indicate the potential to increase mill throughput tonnage and increase annual gold production from Fekola with moderate capital expenditure.

Based on approximately 192 000 m of exploration drilling in 928 drill holes, B2Gold reports an updated indicated mineral resource estimate of 92 810 000 t at 1.92 g/t gold, for a total of 5 730 000 oz of gold, and an inferred mineral resource estimate of 26 500 000 t at 1.61 g/t gold, for a total of 1 370 000 ouz of gold, for the Fekola mine.

Mineral Resources are reported within a pit shell using a $1 400/oz gold price and above a cutoff of 0.6 g/t gold.

Probable Reserves at the start of production at Fekola were 49.2 Mt at 2.35 g/t gold containing 3.7 Moz. These initial reserves are contained within the updated resource.

In addition, pit shells were run using a gold price of $1 250/oz and demonstrate Fekola's resiliency to lower gold prices.

The Indicated Mineral Resource contains 90 670 000 t at 1.94 g/t gold for a total of 5 667 000 oz of gold, and Inferred Mineral Resources of 16 620 000 tonnes at 1.58 g/t gold containing 844 000 oz of gold.

The new mineral resource is contiguous to the north of the current Fekola reserve pit boundary and extends the resource pit boundary 1.2 km to the north.

Exploration drill results further north of the new resource pit boundary demonstrate that gold mineralisation continues to the north, and remains open, indicating the potential to further expand Mineral Resources with additional drilling.

Fekola expanded mine plan and mill expansion study

The B2Gold operations team is currently designing a new mine plan based on the new Fekola Mineral Resource estimate, to establish new Probable Mineral Reserves.

In conjunction, an engineering study is underway to evaluate the Fekola mill expansion potential along with the evaluation of larger mining fleet options.

Current mill production rates have been averaging approximately 5.5 million tonnes per annum (Mtpa) during 2018.

The expansion study is focused on expanding mill throughput to 7.5 Mtpa. The economics of this case will be compared to a baseline throughput of 5.5 Mtpa to 6.0 Mtpa.

Given the capacity of the Fekola primary crusher, SAG mill and ball mill, and engineering work to date, the 7.5 Mtpa throughput can be achieved with an upgrade of the existing ball mill circuit.

Additional process equipment upgrades will be required, which are being determined in the expansion study along with capital and operating cost estimates.

The expansion study is being carried out by the same Lycopodium-Brisbane and B2Gold technical team which performed the prior engineering/design work for the current Fekola mill and infrastructure.

The study is expected to be completed by year-end 2018 and the results will feed into the overall mine/mill expansion evaluation to optimise the economics of the significantly larger, new Fekola Mineral Resource.

As part of the expansion study, the Fekola mill ran a 5-day campaign of 1.1 g/t gold ore in early October to evaluate gold recovery on low-grade material for long-term planning purposes.

The recovery for the 5-day period was 92.7% which was 1.4% higher than the model predicted recovery from feasibility metallurgical test work.

The gold recovery for the low-grade ore was very encouraging, especially with the very high mill throughput over the test period, which was significantly above design throughput.

Ongoing Exploration

For the remainder of 2018, exploration drilling will continue to the immediate north and west of Fekola and at the Anaconda zones approximately 20 km from Fekola.

In 2019, B2Gold plans to continue its successful drilling to convert Fekola's Inferred Resources to Reserves, further explore through drilling the potential to the north and west of Fekola and continue drilling at and beneath the Anaconda saprolite zone.

Additional metallurgical testwork and engineering studies are being carried out on Anaconda towards evaluating the potential for a standalone oxide mine.

The company will release more 2018 exploration results from these zones in November, in conjunction with the third quarter financial results.

In 2018, the Fekola Mine is projected to produce between 420,000 and 430,000 oz of gold with cash operating costs estimated between $345 and $390/oz and all-in sustaining costs estimated between $575 and $625/oz.

Sample Collection and Assaying

The primary laboratories for Fekola are SGS Laboratories in Bamako, Mali, and Bureau Veritas Laboratories in Abidjan, Cote d'Ivoire.

Periodically, exploration samples will be analyzed at the Fekola Mine Lab.

At each lab, samples are prepared and analysed using 50 g fire assay with atomic absorption finish and/or gravimetric finish.

Umpire assays are used to monitor lab performance monthly.

Quality assurance and quality control procedures include the systematic insertion of blanks, standards and duplicates into the core, reverse circulation and aircore drilling sample strings.

The results of the control samples are evaluated on a regular basis with batches re-analysed and/or resubmitted as needed.