Home » ECR Minerals (ECR) » ECR Minerals #ECR – Initial interpretations of pXRF analysis from the first Lolworth Range Niobium Soil Grid

ECR Minerals #ECR – Initial interpretations of pXRF analysis from the first Lolworth Range Niobium Soil Grid

ECR Minerals plc (LON: ECR), the exploration and development company focused on gold in Australia, is pleased to announce the initial geological interpretations from pXRF analysis of the first planned soil grid which is following up previously identified pan concentrate Niobium results to date from the Lolworth Project, Queensland.

ECR Minerals plc has 100% ownership of three exploration tenements (EPM27901, EPM27902 and EPM27903), which covers the Lolworth Range, located 120km west of the famous gold district of Charters Towers. Previous exploration campaigns from 2021 have identified the presence of Gold (Au), Niobium-Tantalum (Nb-Ta) and REE mineralisation within the licenced area. The project is being explored under ECR’s Australian wholly owned subsidiary Lux Exploration Pty Ltd (“LUX”).


  • A total of 1488 planned soil samples have been completed.
  • Samples were taken on a 100m x 50m grid pattern on ridgelines immediately above anomalous streams that were previously found to contain over 5000 ppm Nb (0.5%).
  • In-house pXRF analysis of 1386 samples from the completed soil sampling have shown Nb values up to 146 ppm to be present in soils below the eroded ridgelines.
  • The best Nb values also correlate with a decreasing K/Rb Ratio which suggests fractionation of the pegmatitic rocks and the increased fertility for the mineralisation of critical minerals.
  • More defined follow-up soil sampling and rock chip sampling is on track to be completed this year. 

CEO Andrew Haythorpe commented: “These pXRF results are part of the Lolworth exploration campaign and continue to contribute to the emerging picture there. The method saves both time and money and enables our field team to zero in on areas most likely to contain anomalous mineralisation without the expense of lab testing. Initial pXRF interpretations show consistent indicative Nb values, and as can be seen in Fig 2, the Nb grid values closely correlate with the results of the K/Rb fractionation ratio.”

“These results continue to support our view that Lolworth could be host to a significant Gold, Niobium, Tantalum and REE discovery, and I look forward to reporting back with the next phase of sampling and fieldwork results, along with our initial findings from the fieldwork follow up to the Hurricane project LIDAR survey.”

(Figure 1) Map of the Lolworth Project area with the location of the best Niobium pan concentrate results previously discovered and the location of the completed soil grid:

Figure 1: https://www.ecrminerals.com/images/2023/Fig1_230719

(Figure 2) Two maps showing the comparison of results from pXRF analysis of the soil samples. The fractionation index (K/Rb ratio) shown within the top plan and the Nb results are shown in the bottom plan. Note the highest Nb results spatially correlate to the increased fractionated of the pegmatite rocks (K/Rb ratio):

Figure 2: https://www.ecrminerals.com/images/2023/Fig2_230719


ECR previously announced the identification of Nb-Ta mineralisation from the pan concentrate stream sampling programs on December 23rd 2022 here and February 1st 2023 here. The results of this sampling work concluded with the discovery of an anomalous north-south striking ridgeline in the centre of the project area, (see Figure One above for this location).

A broad soil sampling grid with a spacing 50m x 100m was then created over this ridgeline in order to identify the source rocks for the Nb-Ta. A pXRF spectrum instrument that detects heavy elements such as Nb was used for initial in-house testing for a total of 1386 samples. pXRF testing is a well proven methodology and stands up well in comparison to laboratory results although it cannot be used for quantifiable purposes. Even so the Board are satisfied that the pXRF results provide a firm and accurate identification of anomalous areas that can be sampled in greater detail and concentration, before finally undergoing laboratory testing. Importantly, this early stage sampling method saves  valuable time and money.


It is accepted geological practice that the Potassium (K) and Rubidium (Rb) values of granitic rocks can be used to calculate a fractionation ratio index. During the formation of the granitic host rocks, the Potassium can be replaced by the element Rubidium during the formation of the granite melt. Incompatible elements (such as Lithium and REE’s) are preferentially exsolved from this melt where the K/Rb ratio is broadly less than 150. The initial results of the K/Rb ratio derived from soil pXRF analysis show the lowest numbers are centrally located in the gridded area, (see Figure Two, top map). The K/Rb ratio is also supported by the increase of Nb concentrations within the gridded area, (see Figure Two, bottom map).


The Board has already planned follow up soil sampling within the most prospective areas, with work scheduled to commence by end of August 2023. Rock chip samples have been taken from some of the anomalous stream catchment areas, and results from this work are anticipated within the next three weeks. Further rock chip sampling will be undertaken in other anomalous areas identified from these soil results.

Pan concentrate stream sampling work continues, with some 180 samples awaiting analysis at the laboratory. These samples follow up previous stream results, and it is anticipated that these will assist in identifying additional prospective ridgelines. The sampling process remains focussed on Gold, Nb-Ta and REE mineralisation, in addition to which numerous visible gold samples were noted during recent pan sampling work.


This announcement has been reviewed by Adam Jones, Technical Director of Exploration at ECR Minerals plc. Adam Jones is a professional geologist and is a Member of the Australian Institute of Geoscientists (MAIG). He is a qualified person as that term is defined by the AIM Note for Mining, Oil and Gas Companies.



ECR Minerals plc Tel: +44 (0) 20 7929 1010
David Tang, Non-Executive Chairman

Andrew Haythorpe, CEO



Website: www.ecrminerals.com
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ECR Minerals is a mineral exploration and development company. ECR’s wholly owned Australian subsidiary Mercator Gold Australia Pty Ltd (“MGA”) has 100% ownership of the Bailieston and Creswick gold projects in central Victoria, Australia, has six licence applications outstanding which includes one licence application lodged in eastern Victoria. (Tambo gold project). MGA is currently drilling at the Bailieston Blue Moon Project (EL5433) and undertaking geochemical exploration on the Creswick (EL6148) project and has an experienced exploration team with significant local knowledge in the Victoria Goldfields and wider region.

ECR also owns 100% of an Australian subsidiary LUX Exploration Pty Ltd (“LUX”) which has three approved exploration permits covering 946 km2 over a relatively unexplored area in Queensland, Australia.

Following the sale of the Avoca, Moormbool and Timor gold projects in Victoria, Australia to Fosterville South Exploration Ltd (TSX-V: FSX) and the subsequent spin-out of the Avoca and Timor projects to Leviathan Gold Ltd (TSX-V: LVX), Mercator Gold Australia Pty Limited has the right to receive up to A$2 million in payments subject to future resource estimation or production from projects sold to Fosterville South Exploration Limited.

ECR holds a 90% interest in the Danglay gold project; an advanced exploration project located in a prolific gold and copper mining district in the north of the Philippines, which has a 43-101 compliant resource. ECR also holds a royalty on the SLM gold project in La Rioja Province, Argentina and can potentially receive up to US$2.7 million in aggregate across all licences.

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