Research, Reconnaissance & Geophysics
We have undertaken exploration in a methodical manner from initial targeting and reconnaissance through to more targeted prospecting and subsequent drilling. We have carried out a vast amount of research which has aided the discovery of the Greenbarrow Lithium project.
All work has been carried out whilst upholding the highest quality of detail and very stringent guidelines. We have excellent quality control and quality assurance on all exploration data. This data has been verified and validated using in house techniques as well as external contractors.
Research and reconnaissance
Initial early-stage exploration activities started with a desktop study. This consisted of the collection and integration of historic data from numerous sources including British Geological Survey, Ordinance Survey and old mine plans. This was later followed up with a review of the literature relating to the project area and the region – research which informed our understanding of the stratigraphic setting and structural architecture of the prospect, with previous data and lithium enrichment theories incorporated into our model.
An examination of satellite data for the area was undertaken to further the knowledge of the deposit and to constrain boundaries and margins. This was established using regional LiDAR, ASTER, Sentinel and Tellus geophysical data.
Early-stage grab samples were taken, logged and sent for chemical analysis. This confirmation round of analysis was complimented with field mapping to further constrain the units within the project area.
Image 1: Desktop integration and interpretation of historic data collected lead to the development of older topographic models.
Image 2: Heli-borne field sample mapping and collection near St Austell.
Image 3: The Imerys British Lithium team undertaking an initial round of field mapping.
Imerys British Lithium has utilised numerous sources of historical data which has since been digitised by the team to enable us to create a unique 3D perspective of the regional geology and points of interest. These historical records comprise historic mining plans, field samples and drillhole logs to build up our understanding of the project area. This has since been supplemented with on the ground mapping, sample collection and several phases of drilling.
Cornwall has excellent records of mining within the area due to it once being the hub for mining within the United Kingdom. We have developed on these ideas and used the data to create a unique genesis of lithium enrichment within the SW. In addition to this, Imerys British Lithium conducts detailed mineral tenure reviews and digitises land title plans to produce detailed mineral ownership maps.
Historic mine plan of East Pool Mine.
Figure 2: Imerys British Lithium digitised the workings of an underground tin mine
Figure 3: BLL digitised historic topographic maps to uncover the original topographic surfaces. Material that has been excavated is shown in this image.
Remote sensing and geophysics
When undertaking our exploration, we have taken advantage of the various sources of remote sensing available, enabling us to measure the physical characteristics of the rock from a distance. This is commonly satellite/aircraft data, however we have also employed the use of ground vehicles to undertake this task. From these sources, we are able to obtain regional and local aerial photography, satellite imagery, geophysical/magnetic surveys. Our team will then use geological knowledge to delineate areas of interest prior to any field work being undertaken. This has proven to be an excellent tool in the geologist’s toolbox in drawing conclusions from concealed rock and gaining an understanding of the strata at depth.
The Tellus South West geophysical/magnetic survey completed in 2013 has been significant in outlining the potential sites for further research to take place. We have ranked several targets based on this data and cross referenced this with geological understanding to produce a systematic exploration plan.
Image 5: Regional radiometric survey, false colours of Potassium channel (source: Tellus).
Computer analysis and modelling
Here at Imerys British Lithium, we use computer analysis and complex modelling software to create a 3D representation of the entire SW. We bring together all the data above to create a large-scale model of the region as well as localised places of interest with extra detail and features. This is a critical step in resource development and brings together several aspects of the data collection up until this point.
Image 6: Imerys British Lithium GIS team
Image 7: Pit design wireframe within 3D geological model
Image 8: Section view of mineralised drillholes within preliminary pit design
When mineralisation occurs close to the surface, trenching is a mechanism to obtain samples. This is a technique we have used to establish grade continuity across the deposit, structures and structural controls of the target and to further aid in the delineation of the resource. This is very cost effective compared to drilling and we have already undertaken many trenches within the project area. This data collected through logging and assaying of the samples collected, is then fed into our main exploration database and used to define activities moving forward. Upon reaching bedrock, sampling is undertaken using power tools to obtain fresh rock samples which are then analysed.
Samples are split at the Imerys British Lithium exploration base and analysed using various methods. Lithium is hard to test for due to its atomic mass and compatibility so our team use a number of proxies and parameters to track the grade of mineralisation across the project area. Geochemical evaluation uses methods such as ICP-OES, ICP-AES, Flame AAS, XRF, QEM and XRD to constrain the grade and allow for a full suite of elements to be tested. Only then is the data formulated and inputted into the geological model.
Image 9: Imerys British Lithium channel sampling lithium mineralisation at surface.
Image 10: Mineral vein crossing Imerys British Lithium exploration trench.
Image 11: Imerys British Lithium upholding chain of custody for samples and QA/QC protocal.
Image 12: Splitting of sample ready for geochemical analysis.
New laboratory equipment arriving at BLL’s Roche laboratory.