April 22, 2021

Mineral resources

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Overview – Resources continue to grow at Loncor’s flagship Adumbi Deposit

One deposit, Adumbi, continues to be Loncor’s main focus with 1.777 million ounces of inferred resources and 1.833 million ounces of indicated resources now contained within the US$1600/oz pit shell.

Between 2020 and November 2021 the relatively high- grade resource at Loncor’s Adumbi deposit surged from 1.36 million ounces to 3.66 million ounces of gold, with the inferred transferred into indicated at a conversion rate of 95%. An assessment of the area below these resources suggests there’s the potential to continue the significant growth with the outlined underground exploration target potentially containing the tonnes and grade to elevate Adumbi into a major gold deposit.

Table 1 – Summary of Loncor’s Gold Resources

Loncor's indicated mineral resource - (Total & Attributable Ounces)
Deposit +
Attributable %
Tonnes
(million)
Gold Grade
(g/t Au)
Contained Gold
(000 oz)
Attributable Gold
(000 oz)
Adumbi - 84.68% 28.19 2.08 1.883 1.594
Makapela - 100% (sale pending)** 2.21 8.66 614 614
Total Indicated 30.39 2.56 2.496 2.209
Loncor's inferred mineral resource - (Total & Attributable Ounces)
Deposit +
Attributable %
Tonnes
(million)
Gold Grade
(g/t Au)
Contained Gold
(000 oz)
Attributable Gold
(000 oz)
Adumbi - 84.68% 20.83 2.65 1.783 1.505
Kitenge - 84.68% 0.91 6.60 191 162
Manzako - 84.68% 0.77 5.00 122 103
Total Imbo Project 22.508 2.89 2.090 1.770
Makapela - 100% (sale pending)** 3.22 5.30 550 550
Total Inferred 25.731 3.19 2.639 2.320

Numbers may not add up due to rounding

* Used US$1600/oz gold price for pit optimization and appropriate cost and cut-off assumptions

** Loncor announced in December 2023 the proposed C$13.5M sale of non-core asset of Makapela which when concluded will reduce the controlled and attributable ounces by 1.1M ozs

On June 11 2021, a NI 43-101 technical report on the Imbo Project was filed on SEDAR and confirmed the inferred resource increase to 3.153 million ounces at Adumbi within the Imbo Project, having been prepared by Minecon Resources and Services Limited with an effective date of April 27 2021. A copy of the said report can be obtained from SEDAR at www.sedar.com.

Please refer to the detailed press release dated November 17, 2021 for background on the current Adumbi resource figures. Download PDF

Figure 1: Location of Imbo Project Area (including Adumbi) and Makapela within the Ngayu Greenstone Belt

Location of Imbo Project Area in Ngayu Belt [map]

Figure 2: Imbo Project Simplified Geology

Imbo Project Simplified Geology [map]

Core Logging & Geological Controls

Gold mineralization at Adumbi is found within a BIF (Banded Iron Formation) unit with a strike length of 850 metres and up to 130 metres in thickness (see Figures 1, 3, 5 below: Geologic Plan and Geologic Cross Sections of the Adumbi Deposit). Four main zones of gold mineralization are present within the BIF and are located in:

  • the upper part of the Upper BIF Sequence,
  • the lower part of the Upper BIF Sequence separated by the Carbonaceous Marker, which is essentially unmineralized, and
  • within the Lower BIF Sequence.

There is a higher-grade zone of gold mineralization termed the Replaced Rock Zone (“RP Zone”) associated with alteration and structural deformation that has destroyed the primary host BIF fabric. The RP Zone occurs in the lower part of the Upper BIF and in the Lower BIF, and transgresses the Carbonaceous Marker, located between the Upper and Lower BIF zones, both along strike and down dip.

Geological Modelling and Grade Estimation

The Adumbi 3-dimensional model was constructed by Minecon in collaboration with on site geologists using cross sectional and horizontal flysch plans of the geology and mineralization and was used to assist in the constraining of the 3-D geological model. The mineralization model was constrained within a wireframe at 0.5 g/t Au cut-off grade. Grade interpolation was undertaken using:

  • 2 metre sample composites capped at 18 g/t Au to improve the reliability of the block grade estimates.
  • Ordinary Kriging to interpolate grades into the block model.
  • Relative densities of 2.45 for oxide, 2.82 for transitional and 3.05 for fresh rock were applied to the block model for tonnage estimation.

Pit Optimisation Parameters

To constrain the depth extent of the geological model and any mineral resources, an open pit for the Adumbi deposit was constructed based on the following pit optimisation parameters:

  • A gold price of US$1,600 per ounce.
  • Block size: 16 metres x 16 metres x 8 metres.
  • A thirty-two metres minimum mining width and a maximum of four metres of internal waste was applied.
  • Mining dilution of 100% of the tonnes at 95% of the grade.
  • Ultimate slope angle of minus 45 degrees.
  • Metallurgical recoveries of 91% for oxide, 88% for transitional and 90% for sulphide (based on diagnostic metallurgical testwork as part of PEA).
  • Average mining cost of US$3.29/tonne mined.
  • Average processing cost of US$17.81/tonne for oxides, US$18.92/tonne for transitional and US$22.13/tonne for sulphide.
  • Average general and administration cost of US$4.20/tonne.
  • Mineral resources were estimated at a block cut-off grade of 52 g/t Au for oxide, 0.57 g/t Au for transition materials and 0.63 g/t Au for fresh material constrained by a US$1,600 per ounce optimized pit shell (see Figures 4, 6 and 7 below).
  • Transport of gold and refining costs equivalent to 4.5% of the gold price.
  • No additional studies on depletion by artisanal activity was undertaken since the RPA study of 2014 and the same total amount of material was used by Minecon.

Tonnage/Grade Curve

Grade/tonnage curves for the Adumbi mineral resources at various gold cut-offs are summarised in Table IV and the graph below:

Table IV: Adumbi Mineral Resources at various gold cut-offs

Block Cut-off

Tonnage

Grade

ContainedAu

g/t Au

million tonnes

g/t Au

million ounces

0.0

51.60

2.23

3.70

0.5

50.10

2.29

3.68

1.0

41.15

2.61

3.45

1.5

29.07

3.17

2.97

2.0

21.76

3.66

2.56

2.5

16.06

4.17

2.15

3.0

12.12

4.63

1.80

Grade/tonnage curves for the Adumbi mineral resources at various gold cut-offs are summarised in the graph

The Adumbi deposit is found within Loncor’s Imbo Project, which contains two other deposits, Kitenge and Manzako. As a result of the increased mineral resources at Adumbi, the total inferred mineral resource of the Imbo Project is now 2.09 million ounces of gold (22.508 million tonnes grading 2.89 g/t Au) and is summarised in Table V below. 84.68% of this inferred mineral resource is attributable to Loncor via its 84.68% interest in the Imbo Project.

Table V: Inferred Mineral Resource for the Imbo Project (effective date: November 17, 2021)

Deposit

Tonnage

(Tonnes)

Grade

(g/t Au)

Contained Gold

(Ounces)

Adumbi

20,828,000

2.65

1,777,000

Kitenge

910,000

6.60

191,000

Manzako

770,000

5.00

122,000

TOTAL

22,508,000

2.89

2,090,000

Note: Numbers may not add up due to rounding.

Combined with the Company’s Makapela Project, which is situated approximately 50 kilometres northwest of the Imbo Project, total mineral resources at Loncor’s properties in the Ngayu belt now stand at 2.497 million ounces of indicated mineral resources (30.390 million tonnes grading 2.56 g/t Au) and 2.639 million ounces of inferred mineral resources (25.731 million tonnes grading 3.19 g/t Au) as summarised in Table VI below:

Table VI: Indicated and Inferred Mineral Resources on Loncor Properties in the Ngayu Belt (effective date: November 17, 2021).

Mineral Resource Category

Tonnage

(Tonnes)

Grade

(g/t Au)

Contained Gold

(Ounces)

Indicated

30,390,000

2.56

2,497.000

Inferred

25,731,000

3.19

2,639,000

Note: Numbers may not add up due to rounding.

Quality Control and Quality Assurance

Drill cores for assaying were taken at a maximum of one-metre intervals and were cut with a diamond saw, with one-half of the core placed in sealed bags by Company geologists and sent to the Company’s on-site sample preparation facility. The core samples were then crushed down to 80% passing minus 2 mm and split with one half of the sample up to 1.5 kg pulverized down to 90% passing 75 microns. Approximately 150 grams of the pulverized sample was then sent to the SGS Laboratory in Mwanza, Tanzania (independent of the Company). Gold analyses were carried out on 50g aliquots by fire assay. In addition, check assays were also carried out by the screen fire assay method to verify high-grade sample assays obtained initially by fire assay. As part of the Company’s QA/QC procedures, internationally recognized standards, blanks and duplicates were inserted into the sample batches prior to submitting to SGS Laboratory.

Qualified Person

Mr. Daniel Bansah, Chairman and Managing Director of Minecon, is the "qualified person" (as such term is defined in National Instrument 43-101) who is responsible for the mineral resource estimates and other technical information disclosed in this press release. Mr. Bansah has reviewed and approved the contents of this press release.

Additional resource potential at Imbo and recommendations for further work

There is significant additional resource potential within the Imbo project with a number of the deposits outlined in Figure 2:

  • At the Adumbi deposit, the drilling of additional holes under the proposed pit outline has the potential to create significant underground mineral resources. Between 2020 and November 2021 the relatively high- grade resource at Loncor’s Adumbi deposit surged from 1.36 million ounces to 3.66 million ounces of gold, with 1.88 million ounces being converted from inferred into indicated at a conversion rate of 95%. An assessment of the area below these resources suggests there’s the potential to continue the significant growth with the outlined underground exploration target potentially containing the tonnes and grade to elevate Adumbi into a plus five-million-ounce, Tier 1 gold deposit.
  • At the Kitenge and Manzako deposits (see below), additional drilling may also be undertaken (subject to securing the necessary financing) to further define and increase the inferred mineral resources at these deposits.
  • Ongoing exploration including gridding, soil sampling, trenching and channel sampling is planned to be undertaken at the Imbo East prospect, 10 kilometres southeast of Adumbi along the same mineralized trend as Adumbi in order to generate potential drill targets.

Qualified Person

Peter N. Cowley, who is President of Loncor and a "qualified person" as such term is defined in National Instrument 43-101, has reviewed and approved the technical information on this website relating to Loncor’s mineral properties.

Technical Reports

Additional information with respect to Loncor’s Imbo Project (including the Adumbi deposit) is contained in the technical report of Minecon Resources and Services Limited dated April 17 2020 and entitled "Independent National Instrument 43-101 Technical Report on the Imbo Project, Ituri Province, Democratic Republic of the Congo". A copy of the said report can be obtained from SEDAR at www.sedar.com and EDGAR at www.sec.gov. A further 43 101 Technical Report will be available on SEDAR from June 2021 relating to the April 2021 Resource Increase at Adumbi.

Additional information with respect to Loncor’s Makapela Project, and certain other properties of the Company in the Ngayu gold belt, is contained in the technical report of Venmyn Rand (Pty) Ltd dated May 29 2012 and entitled "Updated National Instrument 43-101 Independent Technical Report on the Ngayu Gold Project, Orientale Province, Democratic Republic of the Congo". A copy of the said report can be obtained from SEDAR at www.sedar.com and EDGAR at www.sec.gov.

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