Tag Archives: mineralisation

Drilling and sampling activities are supervised by a suitably qualified Company geologist who is present at all times. All drill samples are geologically logged by the geologist at the drill site/core yard.

Each sample is sun dried and homogenised. Sub-samples are carefully

riffle split to ensure representivity. The 1.5kg composite samples are then processed.

An equivalent mass is taken from each sample to make up the composite. A calibration schedule is in place for laboratory scales, sieves and field XRF equipment.

Placer Consulting Pty Ltd (Placer) Resource Geologists have reviewed Standard Operating Procedures (SOPs) for the collection and processing of drill samples and found them to be fit for purpose. The primary composite sample is considered representative for this style of rutile mineralisation.

A total of 32 Air-Core holes for 814m are reported here from drilling at the Kasiya Rutile Deposit to obtain samples for quantitative determination of recoverable rutile and Total Graphitic Carbon (TGC).

Placer has reviewed SOPs for Air-Core and found them to be fit for purpose and support the resource classifications as applied to the MRE.

Samples are assessed visually for recoveries. The configuration of drilling and nature of materials encountered results in negligible sample loss or contamination.

Air-Core drilling recovery in the top few metres are moderate to good. Extra care is taken to ensure sample is recovered best as possible in these metres. Recoveries are recorded on the rig at the time of drilling by the geologist. Drilling is ceased when recoveries become poor once Sap rock has been encountered.

The Company’s trained geologists supervise drilling on a 1 team 1 geologist basis and are responsible for monitoring all aspects of the drilling and sampling process.

Air-core drilling samples are recovered in large plastic bags. The bags are clearly labelled and delivered back to the laydown at the end of shift for processing.

No relationship is believed to exist between grade and sample recovery. The high percentage of silt and absence of hydraulic inflow from groundwater at this deposit results in a sample size that is well within the expected size range.

No bias related to preferential loss or gain of different materials is observed.

Geologically, data is collected in detail, sufficient to aid in Mineral Resource estimation.

All individual 1-metre intervals are geologically logged, recording relevant

data to a set log-chief template using company codes. A small representative sample is collected for each 1-metre interval and placed in appropriately labelled chip trays for future reference.

All logging includes lithological features and estimates of basic mineralogy. Logging is generally qualitative.

100% of samples are geologically logged.

N/A

Air-Core samples are dried, riffle split and composited. Samples are collected and homogenised prior to splitting to ensure sample representivity. ~1.5kg composite samples are processed.

An equivalent mass is taken from each primary sample to make up the composite.

The primary composite sample is considered representative for this style of mineralisation and is consistent with industry standard practice.

Techniques for sample preparation are detailed on SOP documents verified by Placer Resource Geologists.

Sample preparation is recorded on a standard flow sheet and detailed QA/QC is undertaken on all samples. Sample preparation techniques and QA/QC protocols are appropriate for mineral determination.

The sampling equipment is cleaned after each sub-sample is taken.

Field duplicate, laboratory replicate and standard sample geostatistical analysis is employed to manage sample precision and analysis accuracy.

Sample size analysis is completed to verify sampling accuracy. Field duplicates are collected for precision analysis of riffle splitting. SOPs consider sample representivity. Results indicate a sufficient level of precision for the resource classification.

The sample size is considered appropriate for the material sampled.

Rutile

The Malawi onsite laboratory sample preparation methods are considered quantitative to the point where a non-magnetic mineral concentrate (NM) is generated.

Final results generated are for recovered rutile i.e, the % mass of the sample that is rutile that can be recovered to the non-magnetic component of a HMC.

The HMC is prepared via wet-table, gravity separation at the Lilongwe Laboratory which provides an ideal sample for subsequent magnetic separation and XRF.

All samples (incl. QA) included in this announcement received the following workflow undertaken on-site in Malawi;

·      Dry sample in oven for 1 hour at 105℃

·      Soak in water and lightly agitate

·      Wet screen at 5mm, 600µm and 45µm to remove oversize and slimes material

·      Dry +45µm -600mm (sand fraction) in oven for 1 hour at 105℃

·      Pass +45µm -600mm (sand fraction) across wet table to generate a heavy mineral concentrate (HMC)

·      Pan HMC to remove retained light minerals

·      Dry HMC in oven for 30 minutes at 105℃

·      Magnetic separation of the HMC by Carpco magnet @ 16,800G (2.9Amps) into a magnetic (M) and non-magnetic (NM) fraction.

Bag NM fraction and send to Perth, Australia for quantitative chemical and mineralogical determination.

·      The NM fractions were sent to ALS Metallurgy Perth for quantitative XRF analysis. Samples received XRF_MS.

Graphite

All samples are initially checked in and processed to pulp at Intertek-Genalysis Johannesburg.

The pulp samples are then dispatched to Intertek-Genalysis Perth where they undergo TGC assay via method C72/CSA.

A portion of each test sample is dissolved in dilute hydrochloric acid to liberate carbonate carbon. The solution is filtered using a filter paper and the collected residue is the dried to 425°C in a muffle oven to drive off organic carbon. The dried sample is then combusted in a Carbon/ Sulphur analyser to yield total graphitic or elemental carbon (TGC).

The graphitic carbon content is determined by eliminating other carbon forms from the total carbon content. The addition of acid to the sample liberates carbon dioxide thus removing carbonate carbon. Soluble organic carbon will also be removed. Insoluble organic carbon is removed by heating the samples at 425°C in an oxidising environment. The “dried” carbon-bearing sample that is analysed in the resistance furnace is considered to contain only graphitic carbon. 

An Eltra CS-800 induction furnace infra-red CS analyser is then used to determine the remaining carbon which is reported as Total Graphitic Carbon (TGC) as a percentage.

Acceptable levels of accuracy and precision have been established. No handheld XRF methods are used for quantitative determination.

Sovereign uses internal and externally sourced wet screening reference material inserted into samples batches at a rate of 1 in 20. The externally sourced, certified standard reference material for HM and Slimes assessment is provided by Placer Consulting.

Accuracy monitoring is achieved through submission of certified reference materials (CRM’s).

ALS and Intertek both use internal CRMs and duplicates on XRF analyses.

Sovereign also inserts CRMs into the sample batches at a rate of 1 in 20.

Three Rutile CRMs used by Sovereign.

Rutile A (AMIS0602) containing TiO₂ XRF 90.62%. The CRM is supplied by African Mineral Standards (AMIS), South Africa.

Rutile B containing TiO₂ XRF 70.71%. The CRM is supplied by OREAS and has been designed and matrix matched specifically for Sovereign.

Rutile C containing TiO₂ XRF 40.76%. The CRM is supplied by OREAS and has been designed and matrix matched specifically for Sovereign.

Two Graphite Standards are used by Sovereign.

MPHLG1 containing 3.22% TGC

TCMG1 containing 7.54% TGC

Both these CRMs are supplied by OREAS and has been designed and matrix matched specifically for Sovereign.

Analysis of sample duplicates is undertaken by standard geostatistical methodologies (Scatter, Pair Difference and QQ Plots) to test for bias and to ensure that sample splitting is representative.  Standards determine assay accuracy performance, monitored on control charts, where failure (beyond 3SD from the mean) may trigger re-assay of the affected batch.

Examination of the QA/QC sample data indicates satisfactory performance of field sampling protocols and assay laboratories providing acceptable levels of precision and accuracy.

Acceptable levels of accuracy and precision are displayed in geostatistical analyses.

Results are reviewed in cross-section using Micromine software and any spurious results are investigated.  The deposit type and consistency of mineralisation leaves little room for unexplained variance. Extreme high grades are not encountered.

Significant mineralisation intersections.

All data are collected initially on paper logging sheets and codified to the Company’s templates.  This data is hand entered to spreadsheets and validated by Company geologists.  This data is then imported to a Datashed5 and validated automatically and then manually.

A transition to electronic field and laboratory data capture is underway.

A Trimble R2 Differential GPS is used to pick up the Air-Core collars. Daily capture at a registered reference marker ensures equipment remains in calibration.

No downhole surveying of Air-Core holes is completed. Given the vertical nature and shallow depths of the Air-Core holes, drill hole deviation is not considered to significantly affect the downhole location of samples.

WGS84 UTM Zone 36 South.

DGPS pickups are considered to be high quality topographic control measures.

The drill spacing and distribution is considered to be sufficient to establish a degree of geological and grade continuity appropriate for further future Mineral Resource estimation.  

Individual 1m intervals have been composited, based on lithology, at a max 2m sample interval for the 32 air-core holes.

Sample orientation is vertical and approximately perpendicular to the orientation of the mineralisation, which results in true thickness estimates, limited by the sampling interval as applied. Drilling and sampling are carried out on a regular square grid. There is no apparent bias arising from the orientation of the drill holes with respect to the orientation of the deposit.

There is no apparent bias arising from the orientation of the drill holes with respect to the orientation of the deposit.

Samples are stored in secure storage from the time of drilling, through gathering, compositing and analysis.  The samples are sealed as soon as site preparation is complete.

A reputable international transport company with shipment tracking enables a chain of custody to be maintained while the samples move from Malawi to Australia or Malawi to Johannesburg. Samples are again securely stored once they arrive and are processed at Australian laboratories. A reputable domestic courier company manages the movement of samples within Perth, Australia.

At each point of the sample workflow the samples are inspected by a company representative to monitor sample condition. Each laboratory confirms the integrity of the samples upon receipt. 

Richard Stockwell (CP) has reviewed and advised on all stages of data collection, sample processing, QA protocol and mineral resource estimation. Methods employed are considered industry best-practice.

Malawi Field and Laboratory visits have been completed by Richard Stockwell in May 2022. A high standard of operation, procedure and personnel was observed and reported.