Kapunda Copper Mine

Kapunda Copper Mine (Cu-REE-Sc-Au) – 100% Terramin

The Kapunda Copper Mine is located on EL5626 in the northern Mount Lofty Ranges, South Australia approximately 35km north of Gawler and 80km from Port Adelaide.

Terramin announced the discovery of significant REE mineralisation at Kapunda 11 February 2014 following the identification of unusually high concentrations of REE and scandium in quartz veins at the historic Kapunda Mine (Table 4). 

Table 4

Table 4: Rare Earth Oxide assay results for KP07 (HREE in italics). Note, yttrium not reported as an oxide by assay laboratory (ALS Global).

The REE discovery represents an exciting avenue for additional value of the Kapunda-Truro project, alongside our copper focus for the area (Wheal Barton). With REE still at relatively high prices as a consequence of the current imposition of export quotas by the world’s dominant producer China, the Kapunda-Truro area presents an attractive target for REE exploration. REE are vital in such high-tech developments as hybrid cars, wind turbines and low energy light bulbs, and their strategic importance in a world embracing green technology has also raised our level of interest in further exploring this region.

Despite the +170 year history of the Kapunda Copper Mine this was the first time such significant levels of REE and scandium have been identified in the project area. The REE mineralisation sampled to date comes from the remanent tail ends of the lodes exposed in the walls of the Stockyard Open Cut that were historically mined for copper (Figure 8). Each lode is made up of a single or a set of sheeted veins typically 10cm to 100cm in width. Initial samples KP04 to KP07 were collected from the Eastern Lode, samples KP08 and KP09 from the Western Lode and sample KP10 from the Eastern Lode. Follow up samples K7001 to K7005 were collected at 1 metre intervals along the hanging wall vein of the Eastern Lode from which KP07 was collected.

Figure 8

Figure 8: Kapunda Mine, with some of the historically worked lodes and sample localities.

Critical Rare Earths

In 2011, the US Department of Energy completed a study entitled, Critical Material Strategy. The study reviewed rare earths based on their role in clean energy as well as supply risk. They identified Neodymium (Nd), Europium (Eu), Terbium (Tb), Dysprosium (Dy) and Yttrium (Y) as critical rare earths (CREE) for both the short and long term. Rare Element includes Praseodymium (Pr) in this list because of its ability to be substituted for Neodymium in high-intensity permanent magnets. The Kapunda REE mineralisation has a relatively high proportion of what are considered the CREE’s.

Figure 9

Figure 9: Critical Matrices based on the US Dept. of Energy “Critical Materials Strategy” report – 2011.

Regional REE Potential

Previous explorers have identified carbonatites and other alkaline igneous rocks in the Kapunda-Truro area. An important economic source of REE are alkaline rocks, skarns and carbonate-replacement deposits associated with alkaline intrusions, veins and dikes cutting alkaline igneous complexes and surrounding rocks.

Diamond exploration was prompted in the project area after South Australian Government geologists identified an alkaline lamprophyre province between Truro and Frankton in the 1990’s. Following this discovery work by Rio Tinto Limited and Flinders Diamonds Pty Ltd in the area identified several other alkaline igneous bodies including two carbonatites.

Radiometrics is a widely used technique in identifying REE deposits as they are often associated with thorium or uranium. Modelling of the aerial radiometric survey over the Truro lamprophyre field (Figure 10) has identified several REE exploration targets. The magnitude of the radiometric measurements over the Truro lamprophyre field is significantly higher than those over Kapunda Mine.

Figure 10

Figure 10: Truro lamprophyre and carbonatite localities shown on combined radiometric (potassium – red, uranium – blue and thorium – green) overlain on magnetic (1VD grey scale) image.

History of the Kapunda Mine

The Kapunda Mine, discovered in 1842, was the first copper mine in Australia, yielding about 13,500t from 68,000t of ore. Low copper prices, the apparent depletion of easily accessible high grade ore and excessive in‐flows of water led to the closure of the mine in 1877. Minor operations continued sporadically until 1912. A portion of the former pit, as it is today, is shown in Figure 11.

Figure 11

Figure 11: View within Kapunda Mine’s Main Open Cut.

Substantial drilling programs were undertaken during the 1960’s and early 1970’s with the majority of the samples only assayed for copper, Figure 12.

Figure 12

Figure 12: Cross section through the Kapunda Mine’s workings 8300N (Copper Range Ltd, 2007).

Investigations of the deposit by previous owners Adelaide Chemical Company in 1993 suggested a remaining resource (pre-JORC) of 3.7 million tonnes at 1.2% Cu for 44,400 tonnes of contained copper within the main pit, with potential for further discoveries along strike.

 

Table 5

Table 5: Assay results for Kapunda Mine rock chip samples (MGA Zone 54 – GDA94).