Chikonga Mine Property
Sutter Mining (Private) Limited a wholly owned Zimbabwe subsidiary of Zephyr Minerals Ltd. has entered into an option agreement to acquire a 75% interest in the Chikonga Mine Property from Hilltouch Investments (Pvt.) Ltd. (“Hilltouch”) a privately owned arms length Zimbabwe company (News Release, 9 May 2022). The 40 hectare property is comprised of four 10 hectare registered claims. All four claims are currently or have previously been mined on a small scale for gold with the first recorded production in 1959. Small scale mining is presently being conducted by Hilltouch on multiple, steeply dipping, parallel narrow reefs (shear zones) stacked across a 350 meter wide, 800 meter+ structural corridor. Recovered gold grades averaged 7.2 g/t, 11.0 g/t and 4.4 g/t in 2019, 2020 and 2021 respectively.
The option agreement remains subject to due diligence, which has been extended while efforts continue by the owner to resolve certain issues necessary to finalize the transaction. The property owner anticipates an additional three to four months will be required for this effort.
Mineralized reefs/shear zones occur as siliceous mica shist and silicified andesite typically hosting bands of fine grained grey and black quartz with disseminated pyrrhotite, pyrite, arsenopyrite, chalcopyrite and gold. Potential for gold mineralized wallrocks is supported by underground sampling in a winze reported by the Regional Geologist, Geological Survey of Rhodesia in 1974* “...a strong wide band of pale grey rock … it contained no quartz or visible sulphides and assayed only 1.0 g/t gold."* While such grades were not of economic interest at the time, in today’s gold price regime low grade gold in walllrocks may be supportive of potential open pit and mechanized underground mining.
Limited sampling of the tailings at the Chikonga Mine indicate an average grade of 0.5 g/t gold. Gold recovery is accomplished by Hilltouch utilizing a stamp mill and standard cyanidation extraction. Limited sampling of the tailings at the Chikonga Mine returned an average grade of 0.5 g/t gold suggesting recoveries in the 90 to 95 percent range during the 2019 to 2021 period, and that the gold mineralization was largely free milling.
The host rocks are predominantly composed of Archean age metamorphosed mafic to ultramafic volcanic rocks with minor banded iron formation and tremolite schist of the Mutare Greenstone Belt. The foliated rock units strike approximately east-west and dip steeply to the south. Post mineralization faulting is expressed as low angle (45 degrees), northwest trending white bull quartz veining.
Main entrance to Chikonga Mine
The project is approximately 20 kilometers west northwest of the town of Mutare and three kilometers by road north of the A3 highway, one of the main highways in the country. The area has excellent infrastructure including high voltage power nearby. The project is located in eastern Zimbabwe in the province of Manicaland near the border with Mozambique centered on 18 degrees 54 minutes and 57 seconds South and 32 degrees 28 minutes and 58 seconds East. The topography is hilly with property elevations above the valley floor in the 30 to 120 meter range. The majority of the project area is covered by woodlands in the hills and farming areas on the valley floors.
Looking west from the No.12 Shaft area
The geological setting of the property is located in the Mutare Greenstone Belt which is an east west trending synclinorium of ultramafic, mafic and banded-iron formations. The lode gold is typically concentrated in fractures and shear zones along brittle-ductile second-order faults. Gold was hydrothermally deposited during carbonatization and serpentinization of ultramafic and mafic rocks and during hydrothermal overprinting of BIF and felsic rocks. The estimated age of the mineralization is 2,700 to 2,600 million years, which is consistent with the age of late Archaean lode-gold mineralization worldwide.
Note: The shear zones in the above map are referred to as “Reefs”. This is a common term for gold bearing rocks in Africa.
The first historical reference to the Chikonga Mine was in a report by geologist N. M. Harrison who examined the property on behalf of the Geological Survey of Rhodesia in 1972. Harrison reported on additional site investigations undertaken between 1972 and 1975 which included descriptions of the reefs, shear zones, mineralization, faulting, the collection and assay of ore samples and engineering aspects of the underground mine. At that time, mining was on a single shear zone which was from one third to one meter wide at the current No. 1 Shaft. Samples results in the Harrison reports range from below 1 g/t to 27 g/t with an average grade in the 5 to 6 g/t gold range. The shear zone strikes east-northeast, dips at approximately 70 to 80 degrees south and is hosted by similarly striking greenstones, schists and minor banded iron formations.
Hilltouch acquired the property in 2005 and has since discovered multiple parallel shear zones in an approximate 350 meter wide structural corridor which strikes east-northeast across the property (see geology map above). The property is currently being mined on a small scale from several of the shear zones. Current mine production is approximately four tonnes per day using hand powered winches to hoist ore and a stamp mill and cyanide leach tanks for gold extraction.
Gold recoveries for the last three years:
Historical gold production records only report recovered grade, hence the insitu grade of the ore is not known. Two samples from the tailings averaged 0.51 g/t gold suggesting recoveries of greater than 90%. According to historic records, only one 41.4 meter core hole has been drilled (1974 or 1975). All current exploration and mining has been derived from surface prospecting and sampling.
Shaft No. 1 headframe, east of the main entrance
The Chikonga Gold Mine prospect was optioned based on numerous pits and shallow shafts dug on multiple parallel gold bearing shear zones stacked across a width of 350 meter in an east–west trending 800 meter+ structural corridor present throughout the property. Other than one 41.4 core hole drilled in the mid 1970’s, the Chikonga Mine property has never been core drilled. The predominant rock types are greenstones (metamorphosed mafic to ultramafic volcanic rocks) with minor banded iron formation and tremolite schist.
Sutter plans to explore the property to define the density and gold grades of the individual shear zones as well as evaluating the host wall rocks for potential gold credits with the objective of identifying a gold resource amenable to open pit and/or mechanized underground mining.an open pit resource.
A Phase 1 program at Chikonga will include detailed mapping and magnetic and Induced Polarization geophysical surveys. This will be followed up with a Phase 2 core drilling program of 3 to 6 short (100 to 150 meter) drillholes. A phase 3 drill program will be predicated on the results of the Phase 2 work program.
Shaft No. 11
Shaft No. 4
Shaft No. 5
* Pg.2, Report on the Chikonga Mine, Chikanga Farm South, Umtali District; 22 September, 1972; N M Harrison, Regional Geologist, Geological Survey Office, Salisbury, Rhodesia