London-listed Tertiary Minerals announced on January 18 that laboratory check analytical results on soil samples from the Jacks copper project, in Zambia, have confirmed and enhanced the provisional results previously reported based on portable X-ray fluorescence (pXRF) analysis taken in the field. 

According to the company, laboratory check multielement analytical results have now been received for 107 soil samples from four sample grids.  

The results show a strong correlation with previously reported field pXRF results, and new scandium analyses – not available with pXRF analysis – allows for the evaluation of key copper/scandium ratios.  

High copper/scandium ratios are considered indicative of hydrothermal copper sulphide mineralisation elsewhere in Zambia, the company said.   

The high copper/scandium ratios obtained from the soil samples taken over copper sulphide mineralisation intersected in the company's 2022 drill programme at Area D validate the application of the copper/scandium ratio, serving to both enhance and extend the Area D soil anomaly beyond the area drilled.  

Additionally, laboratory analysis for 27 contiguous soil samples along a check profile in Area C have exhibited high copper/scandium ratios for a strike length of about 1 km, making Area C another priority for drill testing. 

“These check analyses, and the scandium results, in particular, have materially enhanced the previously reported results and confirm the prospectivity of the priority copper soil anomalies outlined to date at the Jacks project.  

“These results build on a number of recent positive announcements for our Zambian copper projects that highlight the prospectivity of the portfolio we have built over the past 18 months. We are looking forward to an exciting field season in 2023," Tertiary executive chairperson Patrick Cheetham said. 

The Jacks copper prospect covers 141.4 km2 and is located 85 km south of Luanshya in Zambia. Tertiary has earned a 90% interest in the licence from local company Mwashia Resources and recently signed a joint venture and shareholder agreement with Mwashia. 

Following a successful drilling programme at the main Jacks prospect last year, the company conducted a sampling programme in October, where a total of 1 807 soil samples were collected over four separate areas covering 11.5 km2. Samples were analysed in the field using a pXRF analyser on a near real-time basis, allowing daily definition of soil anomalies which were then sampled in more detail on infill lines. 

Multiple soil anomalies were defined by pXRF analysis and results compared favourably with soil anomalies in the vicinity of various orezones at current and past producing mines on the copperbelt. An anomaly threshold of 80 ppm copper was reported. 

Field pXRF analytical results are considered semi-quantitative, the company said.  

While scandium cannot be analysed by pXRF, Tertiary considered it to be an important reference element in discriminating soil anomalies owing to copper sulphide mineralisation.