OK Mine

Axiom, through its wholly owned subsidiary Ozmin Resources Pty Ltd, holds 174 ha of MLs at the OK mining camp, covering areas of historic copper and gold mines and workings. The Company holds or has under application 537 sq km of EPMs surrounding the OK MLs.

Airborne geophysics shows all the historic copper, gold, silver and zinc mines and workings occur along the flanks of a prominent regional north-west trending magnetic low and structural corridor. The Company's tenements deliberately cover much of this corridor. Coincidence of magnetic lows, radiometric highs, surface mineralisation, and structure provide focus for potential development of porphyry-related copper-gold mineralisation.

Extensive historic copper/gold mine workings occur within the OK Mines area and are held by way of a group of five mining leases (ML), two surrounding exploration permit for minerals (EPM) and an EPM Application. The Table below gives the tenement details.

OK Mines Project Tenements

Tenement No.
Tenement Name
EPM 14534
OK Mines
85 sq km
EPM 15529
OK South
360 sq km
EPMA 15445
OK East
92.2 sq km
ML 4805
OK North
18 ha
ML 4806
South OK
18 ha
ML 4809
OK Extended
8 ha
ML 4813
OK Extended
127 ha
ML 5038
3 ha


Location, Access and Topography
The OK Mines Project area is located 110km by mainly unsealed graded road north-northwest of the small regional north Queensland town of Chillagoe.

The topography is a mixture of steep hills developed from an extensive hard chert unit rising above a more gently undulating landscape. The area is covered by moderately thick native woodlands and grass covered slopes. Local relief within the mining leases surrounding the OK Mine is approximately 70m.

Mining and Exploration History
The deposits at OK were discovered in1901 with mining commencing at the OK Mine (the main set of workings) in 1902 and continuing until 1909 when the workings had reached a depth of about 90m. A smelter was erected on site in 1904. Ore was principally derived from the OK Mine and to a lesser extent OK North with minor contributions from OK South and the OK Blocks. The OK North Mine operated between 1908 and 1912 and was reopened in 1937 to provide a small tonnage of flux from remnant pillars for the Chillagoe Smelter.

The ore consisted mainly of secondary copper oxide mineralisation with some primary siliceous mineralisation used as flux. Recorded production from 1904 to 1911 totalled 7,685t of copper, 102kg of silver and 12kg of gold. Recorded production figures from the individual mines are shown in the Table below.

Recorded Production from the OK Mines Area
Mining Period
Approximate Tonnage and Recovered Grade
OK Mine
1901 to 1909
80,000t at 9.2% Cu, 0.14g/t Au, 1.2g/t Ag
OK North
To 1912
6,000t at 7% Cu
In 1937
800t at 5.5% Cu, 2g/t Au, 24g/t Ag
OK South
500t at 10% Cu
OK Blocks

750t at 8% Cu


Project Area Geology and Mineralisation
The host rocks to the copper and zinc mineralisation in the OK Mines area are basalts, mafic volcanics and interbedded cherts. The mineralisation has previously been described as inter-layered, copper and zinc sulphide horizo
ns confined to the pillow basalt horizon. This horizon, in which five separate sulphide lenses have been recorded, can be traced over a strike length of approximately 2.5km from OK North, through OK Mine to OK South. The individual massive sulphide deposits occur as steeply dipping pipe-like bodies which have a close association with a northwest trending shear zone.

At the main OK Mine a stockwork zone of pyrite and chalcopyrite veins occur within a chloritised and silicified basalt which underlies the more massive stratabound mineralisation. Outcrops noted at the OK Mine suggested that the mineralisation occurs at the folded contact between the basalt and chert. From the surface outcrop and from descriptions in prior exploration reports, it appears that the mineralisation in the OK Mines area was probably originally of submarine volcanogenic derivation and may have been remobilised during subsequent folding into the hinges of steeply plunging folds.

The OK North Mine is located approximately 1km north of the OK Mine. Prior exploration reports suggest that the mineralisation occurs in a pipe-like body with the workings extending over 60m in length and to about 60m in depth. Previous mining, from two shafts 36m apart, extracted material below the 20m thick surface gossan. Recorded production from this mine totalled 6,800t at 6.8% Cu. Some high copper and gold values are reported from grab samples from available outcrops and costeans previously excavated over the prospect including:

  • 2.0% Cu, 16.3g/t Au • 0.7% Cu, 12.2g/t Au • 3.9% Cu, 7.9g/t Au • 1.1% Cu, 13.3g/t Au

  • 15.9% Cu, 1.5g/t Au • 30.0% Cu, 1.7g/t Au • 1.0% Cu, 13.5g/t Au • 0.4% Cu, 5.4g/t Au

The OK South Mine workings are located approximately 1km southeast of the OK Mine. Previous production was limited (about 500t at 10% Cu). The 50m deep main shaft is located on a 120m long by 1m wide gossan horizon. Grab sampling of the gossan returned up to 0.7% Cu and 1.6g/t Au from separate samples. A strong soil anomaly occurs over this area and is supported by a moderate IP anomaly. Two percussion holes have been drilled at the southern end of the gossan, and although both holes were prematurely abandoned due to substantial water inflows they did intersect low grade mineralisation with a best result of 6.1m at 0.5% Cu and 0.4% Zn.

Exploration Undertaken by Ozmin
To date Ozmin has acquired the government airborne magnetic data and has utilised this to generate the regional and detailed magnetic intensity images shown in Figure 8. As can be seen, the known occurrences in the area of the OK Mine lease are located on the flanks of a magnetic high immediately adjacent to the northwestern section of a strong linear regional magnetic low. Ozmins' assessment is that similar magnetic features within the project area represent immediate targets for detailed investigation. The company is well advanced with the compilation of the prior exploration data, particularly the geochemical data, into a digital database. The combination of the magnetic and geochemical data, in conjunction with geology, is being used to develop and prioritise targets for follow-up exploration.

Click on image to enlarge

The recently acquired airborne geophysics shows all the historic copper, gold, silver and zinc mines and workings occur along the flanks of a prominent regional north-west trending magnetic low and structural corridor. The Company's tenements deliberately cover much of this corridor. Coincidence of magnetic lows, radiometric highs, surface mineralisation and structure provide focus for potential development of porphyry-related copper-gold mineralisation. Previous explorers classified the OK Mines deposits as volcanigenic massive sulphide (VMS) style, but the indications are that they are porphyry-related.

A 1.6 x 3.2km, 3D pole-dipole Induced Polarization (IP) survey was conducted over the main area of surface mineralisation. This relatively new technology produced a large 1.4km long upper chargeability anomaly in the OK North area and a second extremely large 1.6 x 1.8km chargeability anomaly at depth in the OK Mine area. Both anomalies are interpreted to represent deeper intrusive-related disseminated to massive sulphide.

Ten holes of an 11 hole 5,00m HQ and NQ diamond drilling program has been completed. Six holes tested part of the upper IP anomaly (OK North area); one hole tested below the OK North workings; and one hole tested below the OK Mine. A more powreful drill rig capable of drilling to a depth of approximately 1000m will be used to complete the hole designed to test the deep large anomaly early in 2007.

Three holes intersected massive sulphide within zones of disseminated mineralisation up to 28m in width. One of these holes intersected sulphide mineralisation down dip from an intercept of 35m of 1.5% Cu, 0.47% Zn and 015g/t Au in an earlier hole at OK Mine. Two other holes intersected disseminated sulphide.

During the drilling program, surface and down-hole Electromagnetic (EM) geophysical surveys were conducted in the OK North area with drill results to come. A number of anomalies were produced that will be followed-up in future programs.

As for Cardross, this is the first significant exploration at the OK mining camp since the 1980's. The total amount of drilling completed by previous explorers in 24 holes is 786m of diamond and 624m of percussion. Only four of the diamond drill holes tested deeper than 100m below surface. The average depth of all the drill holes is very shallow at 59m.