Permits & Targets
Chesterfield’s mineral exploration licences, approved or in application
Evlim is new drill target identified between two historic abandoned mines, the Limni pit and Evloimeni Pit.
Records indicate that 90,400 tonnes of copper was mined from Limni from 1937 to 1979. However, taking into account extensive ancient mine workings, it is estimated that around 150,000 tons of copper may have been mined throughout the history of the Limni mine. Evlim comprises an approximate 1km² zone of prospective lavas and dykes that host the mineralisation mined at Limni.
At the southern end, is Evloimeni, a satellite deposit related to the Limni mine that was mined for copper and pyrite. During Q4 2018 the Company carried out drilling at Evloimeni and encountered significant zones of gold mineralisation including 29.8m @ 1.10g (from 13.2m) and 27.9m @ 0.97g (from 8.75m). This suggests that Evloimeni has gold mineralisation occurring beneath overlying copper and pyrite mineralisation.
An analysis of the drilling results at Evloimeni, combined with archive data and field mapping to identify geological controls, suggests this copper and gold system was faulted down and so continues at depth of about 50m at Evlim. Chesterfield commissioned an IP survey at Evlim to test the highly prospective zone.
The initial results of the IP survey are encouraging and indicate a potential extension of mineralisation west of Evloimeni in the downfaulted block. Combined with archival data, including one drill hole from 1983 that returned 0.84% Cu over 11m (from 45m to 56m depth), this has enabled the identification of a drill target likely to host copper and gold mineralisation in lavas.
KinValley is another target recently prioritised for drilling. The Kinousa fault is a 15km long structure that runs to the South East of the historic Limni open pit mine occurring in two parallel trends. Chesterfield has carried out mapping, sampling, geophysics and drilling to build a high-quality database over the course of the past year.
This previously untested target is interpreted to be a shallowly buried VMS deposit formed within a 2nd order extensional graben within the down-thrown hanging wall of the fault and is preserved in favourable stratigraphy. KinValley is within the same trend as a cluster of the historically mined VMS deposits that include Kinousa and Uncle Charles. A geochemical survey (100m line space, 50m sample interval) was carried out and a total of 128 soil samples were taken resulting in a coincident copper anomaly.
The target is also supported by geophysics from a drone Mag survey indicative of a preserved VMS body. KinValley is permitted and is now being prepared for drilling
Further target areas of interest – Kinousa Fault
Chesterfield has identified the hanging wall of the Kinousa fault as a structure likely to host further massive sulphide deposits. A number of preliminary targets have been identified on the fault and work is ongoing to ascertain whether there is enough evidence to elevate these targets to drill targets.
Chesterfield’s Troodos North Project comprises nine Prospecting Permits on the northern flanks of the Troodos Mountains. Troodos North is a historical copper and pyrites mining area due west of the capital Nicosia.
The Troodos North region includes the Skouriotissa copper mined approximately (294kt of copper) is still operational albeit with very low production and the Mavrovouni mine which produced nearly 750kt of copper until its closure in 1974.
Chesterfield’s licences include prospective ground bordering the Skouriotissa mine and Mavrovouni mine.
In addition, recorded production in and adjacent to Chesterfield’s Troodos North Project was:
|Agrokipia A||open cast*||333kt @ 1.0% Cu||30-44% S|
|Agrokipia B||underground*||74kt @ 4.0% Cu||40% S|
|Memi pyrite||open cast*||2.1 Mt @ 26% S|
|Kokkinoyia||underground**||481kt @ 2.0% Cu||30-40% S|
|Alestos||open cast**||661kt @ 0.9% Cu|
|Kokkinopezoula pyrite||open cast**||5.5 Mt @ 24% S|
*in Chesterfield licences
**adjacent to Chesterfield licences
There is widespread direct evidence for copper mineralisation, such as outcrops of primary copper-pyrite-sulphide, malachite staining and ancient slag piles. The high-grade copper at the Agrokipia A & B and Kokkinoyia mines demonstrates grade potential, whereas the two large pyrite mines at Memi and Kokkinopezoula demonstrate the size potential in the area. There are potential extensions around known mines and prospects.
Discovery South is an area south of the Troodos Mountains previously explored by the UN. Nine prospects have been identified by Chesterfield while archival data is currently being digitised. Desk studies and first pass field assessment started in 3Q 2019.
To explore its large licence areas, Chesterfield will focus on identifying the most favourable positions within the volcanic units to host VHMS deposits. In particular, the proximity to primary fault systems is considered important to form large VHMS systems. Another important consideration for targeting the mineralisation is unravelling the post-volcanic deformation (rotation and tilting). Some basic exploration constraints for VHMS exploration in Cyprus can be highlighted:
- The largest and highest-grade deposits will be in volcanic rocks.
- The massive pyrite bodies are likely to be buried by later volcanic eruptions, so understanding the local eruption-hydrothermal cycle will constrain favourable stratigraphic intervals.
- Chemical sediments (umber, ochre) are direct proxies for a hydrothermal eruption but are deposited distal to associated massive pyrite bodies. They provide useful stratigraphic constraints.
- Ancient seafloor topography (e.g. rift valleys) would have greatly influenced the site of deposition and subsequent preservation of the massive pyrite bodies. It is critical to understand the rotation of fault blocks during sea-floor rifting.
- Alteration zones are expected in the footwall to massive pyrite bodies and may be prospective themselves.
- Larger alteration zones indicate larger, more persistent hydrothermal systems and should develop larger massive pyrite bodies.
- Identification of the primary rift faults is important given that Troodos was rotated ca. 90° counter- clockwise, such that the primary rift faults are now orientated north-south.
- Dolerite dyke intrusion should be broadly sub-parallel to the main rift faults.
- Later faulting has clearly shuffled the Troodos rocks such that deposits may have been translocated.