Mineral Reserves are reported from pit designs and underground stope designs based on Indicated Mineral Resources. Mineral Resources are reported inclusive of those Mineral Resources that have been converted to Mineral Reserves.

Economic parameters such as mining costs, processing costs, metallurgic recoveries and geotechnical considerations have been applied to determine economic viability of the Mineral Reserves based on a gold price of US$1,250 per ounce (“/oz”). Mineral Reserves contained in stockpiles that meet the project-specific Mineral Reserve cutoff grades are also included for the Fekola and Otjikoto Mines and the Masbate Gold Project.

Mineral Resources amenable to open pit mining are constrained with conceptual pit shells defined by economic parameters and using a gold price of US$1,400/oz. Mineral Resources amenable to underground mining methods are reported above cutoff grades defined by site operating costs and using a gold price of US$1,400/oz. Mineral Resources contained in stockpiles that meet the project-specific cutoff grades are also included for the Fekola, Masbate and Otjikoto Mines. Gold grades are expressed in grams per tonne of gold (“g/t Au”).

Except where stated otherwise, Mineral Reserve and Resource estimates for B2Gold’s operating mines have been updated to account for mining depletion, using topographic surfaces as of December 31, 2018. These Mineral Reserve and Resource estimates are reported by project/mine on both a 100% project basis reflecting the total Mineral Resources and Mineral Reserves and the applicable project specific attributable basis reflecting B2Gold’s ownership interest (details in notes below).

Limon Reserves

Click here NI43-101 Technical Reports

Underground Resreves Notes:

1. CIM (2014) definitions were followed for Mineral Reserves.
2. Mineral Reserves are estimated at a cut-off grade of 2.75 g/t Au.
3. Mineral Reserves are estimated using an average long-term gold price of US$1,350 per ounce
4. Bulk density is 2.5 t/m³.
5.  Numbers may not add due to rounding.
6. A mining extraction factor of 95% was applied to the underground stopes.  Where required a pillar factor was also applied for sill or crown pillar.  A 100% extraction factor was assumed for development.

Surface Reserves Notes:

1. CIM (2014) definitions were followed for Mineral Reserves.
2. Open pit Mineral Reserves are estimated at a cut-off grade of 1.32 g/t Au, and incorporate estimates of dilution and mining losses.  Mineral Reserves are reported in dry tonnes.
3. Mineral Reserves are estimated using an average long-term gold price of US$1,350 per ounce.
4. Bulk density averages 2.26 t/m³.
5. Numbers may not add due to rounding.

Limon Resources

Click here NI43-101 Technical Reports

Resource Notes:

1. CIM (2014) definitions were followed for Mineral Resources.
2.  Mineral Resources are based on 100% ownership.
3. Mineral Resources are estimated at cut-off grades of 1.25 g/t Au for the Limón open pit, 1.20 g/t Au for the Tailings, and 2.25 g/t Au for underground in Santa Pancha 1, Santa Pancha 2, and Veta Nueva.
4. Mineral Resources are estimated using a long-term gold price of US$1,500 per ounce.
5. Numbers may not add due to rounding.

Libertad Resources

Click here NI43-101 Technical Reports

Notes:

1. CIM (2014) definitions were followed for Mineral Resources.
2. Mineral Resources are based on 100% ownership.
3. Mineral Resources are estimated at cut-off grades ranging from 0.62 g/t Au to 0.68 g/t Au for open pits and 2.80 g/t Au to 2.85 g/t Au for underground.
4. Mineral Resources are estimated using a long-term gold price of US$1,400 per ounce.
5. Bulk density is 1.70 t/m³ to 2.65 t/m³.
6. Numbers may not add due to rounding.

Pavon Gold Project Resource Estimate¹

Footnotes:

1. https://www.b2gold.com/_resources/financials/2013-AIF.pdf
2. All technical information related to the Pavon Gold Project is based on the B2Gold Annual Information Form dated March 27, 2015, see Resources and Reserve details in the appendix

The Borosi Concession Projects

Overview; Calibre Mining Corp. has outlined mineral resources in four areas within the Borosi Concessions. (Click here for the Techncial Reports)

Within the Projects currently owned 100% by Calibre Mining, in 49% joint venture with IAMGOLD, and 33% in joint venture with Santa Rita Mining Inferred Resource total;

60,837,000 tonnes grading 1.53 g/t AuEq containing 2,992,469 ounces of gold equivalent.

Additionally within the Rosita D JV (33% Calibre) indicated resources host 252,000 gold equivalent ounces.

Notes:
1. Riscos de Oro and La Luna currently optioned to JV with IAMGOLD 

Primavera Gold-Copper Porphyry; Calibre Mining Corp. announced the maiden resource on the 100% Owned Primavera Gold-Copper porphyry in December of 2016. The inferred Resources is 45 million tonnes grading 0.84 g/t AuEq containing 1.2 million ounces gold equivalent.

Inferred Resource at a cutoff of 0.5 g/t Au for the Primavera Au-Cu Porphyry Deposit

Notes:
1. CIM definition standards were followed for the resource estimate.
2. The 2016 resource models used Ordinary Krig grade estimation within a three-dimensional block model with mineralized zones defined by wireframed solids (HG=high grade, LG= low grade, sap=saprolite).
3. A base cutoff grade of 0.5 % g/t Au was used for reporting resources.
4. Densities varied by material type and ranged from 2.4 for saprolite to 2.71 for diorite and the volcanics have variable estimated densities using inverse distance.
5. Gold Equivalent (AuEq) calculated using $1300/oz Au for gold, $2.40/lb for Copper, and $20.00/oz Ag for silver and metallurgical recoveries are assumed to equal for all metals. 

The Primavera Project NI 43-101 Inferred Resource Estimate was prepared by independent qualified person Todd McCracken, P. Geo. of WSP. The resource estimate is based on the combination of geological modeling, geostatistics and conventional block modeling using the Ordinary Krig methodology of grade interpolation. The mineralized zones were defined by wireframed solids consisting of HG=high grade, LG= low grade, and sap=saprolite. The mineral resources were estimated using a block model with parent blocks of 10m X 10m X 5m. A capping study was made using histograms, probability plots, quantile plots and deciles plots to define the capping values resulting in capping value of; HG: 2.7 g/t Au; 9 g/t Ag; 1% Cu and LG: 1.7 g/t Au, 3.6 g/t Ag and 0.46% Cu.

The WSP Resource Estimate also evaluated the Primavera Deposit at a range of cutoff grades between 0.1 g/t Au and 0.9 g/t Au. Results are as follows;

Inferred Resource at Range of Cutoff Grades for the Primavera Au-Cu Porphyry Deposit

WSP also completed whittle analyses to estimate an open pit-constrained Inferred resource with results as follows;

Open Pit-Constrained Inferred Resource at a 0.5 g/t Au Cutoff- Primavera Au-Cu Porphyry Deposit

Notes:
1. Whittle optimized open pit.
2. Mining Cost $2.25/t mined, Processing Cost $20/t processed (included G and A and Selling Costs)
3. Mining Dilution 5% @ 0 grade and Mining Recovery 95% both applied globally.
4. Metal Recovery; 90% for Au and 90% for Cu.
5. Metal prices; $1300/oz Au and $2.40/lb Cu
6. Overall slope angles; 200 overburden, 420 saprolite, and 440 in rock.

WSP ‘s resource estimate for Primavera is based on drill core assay results from a total of 33 holes totaling 13,491 metres of drilling and 52 trenches totaling 660.9 metres. Statistical and geostatistical analysis was completed on the total database to assess the characteristics and distribution of gold, copper and silver values across the deposit. Variograms were generated for gold, copper and silver and search parameters established for grade interpolation using kriging.

Eastern Borosi Project in Joint Venture with IAMGOLD (51% IAMGOLD / 49% Calibre Mining); Calibre Mining Corp. has outlined additional Inferred resources;

In May 2018, on behalf of the joint venture between IAMGOLD (51%) and Calibre Mining (49%), Roscoe Postle Associates Inc. (“RPA”) has completed initial resource estimates for the Blag, East Dome, Guapinol, and Vancouver veins, as well as updated Mineral Resource estimates for the Riscos de Oro and La Luna veins, which are part of the Eastern Borosi joint venture. The resource models assumed open pit extraction for the La Luna veins, and underground mining extraction for the other veins. The underground resource estimate comprises Inferred Resources totaling 3,219,000 tonnes grading 6.03 g/t Au and 104 g/t Ag for 624,000 ounces of contained gold and 10,758,500 ounces of contained silver. The open pit resource comprises inferred resources totaling 1,199,000 tonnes grading 1.98 g/t Au and 16 g/t Ag, for 76,500 ounces of contained gold and 601,000 ounces of contained silver. A summary of the Inferred Mineral Resource estimate is presented in the table below. For full details please see news release Calibre Mining Announces that Joint Venture partner IAMGOLD has reported an Inferred Mineral Resource Estimate of 812, 000 Gold Equivalent Ounces on the Eastern Borosi Project, Nicaragua. (https://calibremining.com/news/2018/calibre-mining-announces-that-joint-venture-partner-iamgold-has-reported-an-inferred-mineral-resource-estimate-of-812-000-gold/)

INFERRED Mineral Resources IAMGOLD Corporation / Calibre Mining Corp. – Eastern Borosi Project

Notes:
1. CIM (2014) definitions were followed for classification of Mineral Resources.
2. Mineral Resources are estimated at a cut-off grade of 2.0 g/t AuEq for resources potentially mined by underground methods and 0.42 g/t AuEq for resources potentially mined by open pit methods.
3. Gold equivalent values were calculated using the formula: AuEq (g/t) = Au (g/t) + Ag (g/t) / (101.8)
4. Mineral Resources are estimated using a long-term gold price of US$1,500 per ounce of gold, US$23 per ounce of silver.
5. A minimum mining width of 2.4 m was used for underground and 3 m for open pit.
6. Bulk density is 2.65 t/m3 for Blag, East Dome, Riscos De Oro, and La Luna, and 2.60 t/m3 for Guapinol and Vancouver.
7. East Dome is included in the Blag resource model and Vancouver is included in the Guapinol resource model.
8. Numbers may not add due to rounding.
9. Mineral Resources that are not Mineral Reserves do not have economic viability

Siuna Gold Project ; Calibre Mining Corp. has outlined additional Inferred resources;

In February 2011, Calibre announced new gold and silver resources for the 100% owned Cerro Aeropuerto deposit. The National Instrument 43-101 (“NI 43-101”) compliant, inferred resource totals 707,000 ounces of gold and 3,144,500 ounces of silver (757,000 ounces of gold equivalent).

Inferred Resource for Cerro Aeropuerto (using a 0.6 g/t AuEq cutoff grade)

1. Resource models used Inverse Distance grade estimation within a three-dimensional block model with mineralized zones defined by wireframed solids and a base cutoff grade of 0.6 g/t.
2. Resource Estimate for Cerro Aeropuerto detailed in Technical Report titled NI 43-101 Technical Report and Resource Estimation of the Cerro Aeropuerto and La Luna Deposits, Borosi Concessions, Nicaragua by Todd McCracken, dated April 11, 2011.
3. Gold Equivalent (AuEq) for C. Aeropuerto was calculated using $1058/oz Au for gold and $16.75/oz Ag for silver, and metallurgical recoveries and net smelter returns are assumed to be 100%.

Rosita D Joint Venture with Rosita Mining (Rosita 66% / Calibre 33%); Calibre Mining Corp. has outlined additional resources;

In February 2016 the Rosita D Resource Update included; Stockpile resources upgraded to Indicated category, Total gold and copper resources increased from the 2012 estimate by 24% and 8% respectively, and the maiden tailings resources estimated.

The resource estimate in stockpiles totals 70.9 million lbs. of copper and 96,660 oz. of gold and 46.2 million lbs. of copper and 50,330 oz. of gold in the Indicated and Inferred categories respectively. Indicated resources total 6.46 million tonnes grading 0.47 grams gold per tonne and 0.5% copper per tonne whilst Inferred resources total 3.44 million tonnes grading 0.46 grams gold per tonne and 0.61% copper per tonne in a series of stockpiles located near the former producing Santa Rita gold-copper open pit mine. These estimates have been based on a US$10 net smelter return (“NSR”) cut off. In addition, the Company is also reporting maiden Inferred resources of 1.96 million tonnes grading 0.56 grams gold per tonne at cut-off of 0.3 g/t gold in tailings located proximal to the Santa Rita stockpiles. 

The results of these resource estimates, which are summarized in Table below, were prepared by Yungang Wu., P. Geo., an independent Qualified Person as defined by NI 43-101. 

Table - Indicated and Inferred Mineral Resource Estimate, Santa Rita Stockpiles and Tailings

1. The quantity and grade of reported Inferred resources in this estimation are uncertain in nature and there has been insufficient exploration to define these Inferred resources as an Indicated or Measured mineral resource and it is uncertain if further exploration will result in upgrading them to an Indicated or Measured mineral resource category.
2. A gold price of US$1,200/oz, copper price of US$2.5/lb and silver price of US$16/oz were utilized in the NSR calculations of block values with process recoveries of 80% for gold, 35% for Cu (10% deducted for smelting) and 65% for silver. These values were equated against a cut-off grade of US$10 for stockpiles and 0.3 g/t Au for tailing mineral resources.
3. For the cut-off grade, mining costs were assumed at US$1.00/t, process costs at US$7.50/t and G&A costs at US$1.50/t 

The updated NI 43-101 resource estimates incorporated the results of a reverse circulation drilling campaign completed by Rosita in the fourth quarter of 2015. This work included 1,040 m of drilling in 55 vertical in-fill holes on five stockpiles located near the former Santa Rita open pit and 87 auger holes totaling 460 metres in a portion of the tailings piles, drilled in 2012 and 2013. Drilling to test the tailings only tested a small portion of the overall tailing piles which remain open for possible resource expansion

The stockpiles at the project were generated over a 17-year operating life from 1959 to 1975 at the Santa Rita open pit mine. A total of 5.4 million tonnes averaging 2.06% copper, 0.93 grams gold and 15.08 grams silver per tonne were mined. In addition to the stockpile resources, the concessions also include 15 exploration targets for gold-copper skarn and porphyry mineralization. 

Notes (for all Resource Estimates):

1. CIM definition standards were followed for the resource estimate.
2. Numbers may not add exactly due to rounding.
3. Mineral Resources that are not mineral reserves do not have economic viability
4. The quantity and grade of reported inferred resources in this estimation are uncertain in nature and there has been insufficient exploration to define these inferred resources as an indicated or measured mineral resource and it is uncertain if further exploration will result in upgrading them to an indicated or measured mineral resource category.

Qualified Person

Darren Hall, MAusIMM, MSME, SVP & Chief Operating Officer Calibre Mining Corp is a “qualified person” as set out under NI 43-101 has reviewed and approved the scientific and technical information in this press release.