Exploration Drilling

British Lithium has conducted a number of successful drilling campaigns using both Reverse Circulation and Diamond Core drilling.

Initial Drilling (Phase 1)

The purpose of initial drilling was to confirm and validate geophysical, surface mapping and rock-chip data at surface and to establish the extent of lithium mineralisation at depth and to provide representative samples for metallurgical research and process design.

In Q2 of 2019, British Lithium successfully used reverse circulation drilling as a cost-effective drilling program to support resource validation (Figure 7). The programme consisted of 6 holes drilled by a Comacchio MC900P reverse circulation rig mounted on steel track crawler with a Progradex EL350 sampler and was the first ever lithium exploration drilling program in the UK. Rigorous QA/QC procedures were documented and followed to ensure sample representivity and quality. All samples produced were bagged at site and transported to the British Lithium sample preparation facility in Roche, Cornwall, prior to geochemical analysis (Figures 8, 9).

Wardell Armstrong International performed an independent review of the RC drilling program protocol and quality control and assurance. They concluded the drilling programme generated high quality data across all intervals and all drill holes.

The initial phase 1 drilling campaign was successful in confirming the existence of substantial lithium mineralisation from surface. Based on surface sampling, trenching, logging, and geophysical and drilling data, British Lithium prepared detailed cross-sections, longitudinal vertical sections, level plans, 3D orebody modelling, resource, and target estimation.

Down Hole Logs

To extract the most value from the drill programmes, British Lithium Limited has successfully conducted geophysical surveys of selected drill holes measuring the physical properties of the rocks in situ. These data enhance our lithological and structural understanding of the mineralisation (Figures 10, 11) through delineation of lithological features and structures that will impact the resource model.

Figure 12: Acoustic and optical analysis of British Lithium Drill Hole
Figure 12: Acoustic and optical analysis of British Lithium Drill Hole
Figure 13: Down hole survey of British Lithium exploration holes
Figure 13: Down hole survey of British Lithium exploration holes

Diamond Drilling (Phase 2)

British Lithium has now completed a diamond drilling program to further delineate the mineralisation and to provide whole core samples for future lithological classification and structural information. The first diamond hole completed on 4 December 2019, successfully extended lithium mineralisation previously intersected from surface to a depth of 201 m, down to an incredible 354 m.

The diamond core method used was pioneered in Western Australia and used an HQ3 diamond bit, and a triple core barrel retrieved by wire-line winch through the drill string without the need to withdraw the drill string from the hole. The triple barrel system gives the highest recovery of 63 mm core in broken or kaolinised ground.

British Lithium and its contractor Priority Drilling proved the efficacy of operating onsite 24 hours per day, seven days per week and drilled 4 diamond core holes in mid-winter, prior to Christmas, without accident or injury. The remote location of British Lithium’s project ensured that overnight operation did not create any disturbance to communities.

The diamond core is being processed in British Lithium’s process laboratory in Roche to facilitate metallurgical research and process development. British Lithium is the only operator in Cornwall with its own inhouse metallurgical laboratory.

Objectives of the diamond drilling program are as follows:

  • Provide solid core samples for metallurgical research. By using core samples from varying depth representative samples relating to various stages of the mine plan and metallurgical variability analysis can be performed.
  • Establish the extent of lithium mineralisation extension at depth. The existing RC holes ended at 201 m, still within mineralisation and so the depth of mineralisation was unknown.
  • Provide core for determination of moisture content and density data over the depth tested. Bulk density data is a key factor in resource estimation as it allows conversion of volume to tonnes of rock.
  • Verify the data generated by the RC program by twinning two of the earlier 6 RC holes. These data will be utilised by the independent geologist to declare our maiden JORC Mineral Resource Estimate. Verification will compare assay values and intervals between the twin holes for comparable meters and seek to understand the cause(s) of any difference.
  • Show the validity of using the cost-effective RC method on this deposit to facilitate the majority of future resource drilling.
  • Conduct detailed lithological, geotechnical and structural logging of the lithium nearing and other mineralisation.

The diamond core is being processed in British Lithium’s process laboratory in Roche to facilitate metallurgical research and process development. British Lithium is the only operator in Cornwall with its own inhouse metallurgical laboratory.

British Lithium's in-house laboratory

New laboratory equipment arriving at BLL's Roche laboratory
New laboratory equipment arriving at BLL's Roche laboratory