As it looks to progress the development of its Adumbi project, Canadian gold exploration company Loncor sent drilling tenders to a number of drilling companies to bid on a 11 000 m deep drilling programme at the priority gold exploration target below the Adumbi $1 600/oz pit shell.

Fifteen intersections are proposed at the Adumbi project below the pit shell to outline an inferred underground mineral resource. Of the 15 proposed intersections, six interceptions will be wedged off nine deeper holes to save time and costs.

Located on the Ngayu Greenstone Gold Belt, in the northeast of the Democratic Republic of Congo (DRC), current exploration at the project is proposed to be undertaken with two core rigs that will start a deep drilling programme at Adumbi by the beginning of April.

This drilling programme is estimated to be finished by year-end, at which time an underground inferred mineral resource estimate will be carried out.

Adumbi is situated 220 km from Africa’s largest gold mine – global gold mining houses Barrick Gold’s and AngloGold Ashanti’s Kibali gold mine, which is a hub for many major mining-related contractors in the DRC.

The Adumbi project currently has an indicated mineral resource of 1.88-million ounces of gold, with 28.185-million tonnes grading 2.08 g/t gold; while the inferred mineral resource is calculated at 1.78-million ounces of gold, at 20.83-million tonnes grading 2.65 g/t gold.

These values are situated within the pit shell, with 84.68% of these mineral resources being attributable to Loncor.

“The recent non-dilutive sale of Makapela for C$13.5-million has strengthened Loncor’s hand significantly,” says Loncor CEO John Barker.

He adds that this enables Loncor to drill for the potential ounces below the 3.66-million-ounce, high-grade resource delineated within the Adumbi pit outline.

Additionally, confirmation of significant ounces at depth would enable Loncor the flexibility to explore the economics of a combined openpit and underground project at Adumbi.

A smaller pit would reduce strip ratios, and the underground ounces would increase the grades through the processing plant with the overall target being an enhanced economic profile for the combined openpit and underground scenario, Loncor reports.

“With the recent DRC general elections passing successfully, the country continues to draw growing interest from international companies seeking world class mineral and mining opportunities,” says Barker, adding that Loncor believes the developing Adumbi places Loncor at the forefront of such interest.

The Adumbi resource remains open at depth below the $1 600/oz pit shell, with the maximum depth of pit shell bottom 550 m below surface, with the favourable banded-ironstone formation host increasing in thickness.

Loncor estimates the potential Adumbi underground exploration target as between 8.9-million tonnes to 9.6-million tonnes, grading at between 4.7 g/t and 4.9 g/t gold, to a depth of 800 m.

However, Loncor notes that these potential quantities and grade are conceptual in nature as there has been insufficient exploration to define a mineral resource. As such, it is uncertain if further exploration will result in the Adumbi underground exploration target being delineated as a mineral resource.

Loncor’s independent geological consultants Minecon Resources and Services undertook the Adumbi underground exploration target tonnage and grade estimation ranges.

The Adumbi three-dimensional (3D) model was constructed using cross sectional and horizontal flysch plans of the geology and mineralisation and was used to assist in constraining the 3D geological model.