Gold Occurrences in North Queensland

Part of the Townsvllle 1:250 000 Geological Sheet area is included in the Charters Towers and Ravenswood Gold and Mineral Fields, but gold production has been small. The main mining centres and types of deposits are listed.

The Grass Hut and Fanning deposits, like those of Charters Towers and Ravenswood, are associated with the Ravenswood Granodiorite Complex. In the other centres, the gold mineralization appears to be related to late Palaeozoic intrusives in Devonian sediments.

Gold is also known to occur at Bunkers Hill (Ravenswood Granodiorite Complex and Kirk River Beds), Horse Camp Creek (Ravenswood Granodiorite Complex), Mount Squarepost and Magnetic Island (uppermost Carboniferous granite), Mount Elliot (Lower Permian granite), Ponto (Argentine Metamorphics), and Six Mile or Argentine Extended (uppermost Carboniferous granodiorite).

Total production of gold in the Geological Sheet area has been low, but returns separate from those for the Ravenswood and Charters Towers Fields are not available.

Charters Towers (134km by rail from the coast at Townsville) is the principal centre of the Charters Towers Gold and Mineral Field. Although production from Charters Towers has been small since the 1920s, its total recorded production since its discovery in 1871 to the end of 1964, except for a small quantity from the Cape River area, was 6,805,510 fine ounces of gold, and until 1959 it had produced more gold than any other mining centre in Queensland. Up to 1916, when practically all mining ceased, 1,000,565 ounces of silver and 3,684 tons of lead were also recovered.

All the important mines were located in the Ravenswood Granodiorite Complex. The lodes are simple or composite tabular bodies, wholly or partly within fissures. The fissures belong to two sets of faults which dip to the east-northeast at 27° to 36°, and to the north or north-west at 23° to 50°. The fissure walls are well defined and are commonly slicken-sided. The lodes are formed of one or more quartz veins separated by crushed and altered country rock. In the major fissures two or more separate veins may occur in parallel or branching channels. Some of them are separated by unaltered country rock and were mined as independent bodies as in the Day Dawn and Brilliant systems.

The ore shoots were irregular in shape and no consistent direction of pitch is apparent. A crude en echelon arrangement of the shoots in parallel veins is discernible in places. The deepest workings were on the Brilliant lode (3,000 ft) and on the Day Dawn lode (2,700 ft). Only a few of the other lodes were worked below 1,000 feet. In all cases values became poorer with depth.

The ore is a simple mesothermal mineral essemblage: the normal primary constituents, in addition to native gold, are quartz, pyrite, galena, and sphalerite. The less common minerals include calcite, chalcopyrite, gypsum, barite, arsenopyrite, native arsenic, and an unidentified telluride. Galena was important as an indicator of gold values. The localization of the ore does not appear to have been related to the country rock or to intersection of the lodes either by dykes, early barren quartz veins, or faults (except in the last case for minor local enrichment).

Total yield of gold from the Charters Towers and the Cape River goldfields to date exceeds 211,000 kg. Maximum production was reached in 1899 with 9940kg. Renewal of prospecting in old workings in the Black Jack area led to production of some 1245kg between 1934 and 1951. Since that date gold mining on the field has languished. Ore occurred in shoots in fissure reefs and showed general impoverishment in depth. The lowest workings reached 915m. In the absence of favourable information as to reserves and in view of the heavy cost of dewatering and reconditioning, it is considered unlikely that the central connected group of workings, including the former main producers, could be successfully reopened. Future prospects on the field must therefore, depend on further exploration and developmental work on outlying reefs which are widely distributed in the surrounding areas.

Groups of workings at the Broughton, Rishton, Dreghorn, St. Paul’s, Mount Leyshon, Lighthouse, Windsor, Southern Cross, Fern Springs and Newhaven still offer possibilities for prospecting activity particularly in regard to selected portions adjacent to old workings.

Mount Leyshon

Gold has been mined in volcanic rocks which postdate the Ravenswood Granodiorite Complex at Mount Leyshon and Mount Wright. At Mount Leyshon the gold occurs in rhyolite and dacite agglomerate (Pzo) in an old volcanic vent at the contact between the Ravenswood Granodiorite Complex and the Cape River Beds. The gold is disseminated throughout the rock, or occurs in association with thin limonite veins and stringers which permeate the country rock. Values are erratic. Other primary minerals include pyrite and chalcopyrite. Production from 1887 to 1946 was about 38,000 fine ounces of gold from about 208,000 tons of ore.

Lucky Creek Goldfield

This goldfield of approximately 50 km² can be found in the far north-west corner of the Charters Towers Mining District. This location is also noted on the Clarke River Geological Sheet. Gold has been mined from the Lucky Creek Goldfield near the headwaters of Lucky Creek, which is a tributary of the Burdekin River. The gold is in lenticular quartz reefs that conform to the bedding of steeply-dipping sediments of the Lucky Creek Formation. Gold mineralization occupied a length of 1,000 feet and a width ranging from 8 inches to 2 feet. The deepest mine was the Try Again, which was worked to a depth of 115 feet. Production reached a peak in 1907, when about 250 tons of ore was mined to yield an average of 2 oz gold per ton.

RAVENSWOOD

Ravenswood (87 km by rail from Townsville to Mingela thence 42km by road). This also was one of the major gold-producing areas of Queensland, the total yield to the end of 1963 being some 900,000 fine ounces. The field was discovered in 1868, but early development was slow and it was not until between 1898 and 1912 that annual production was consistently high and more than half the total yield was produced.

Most of the yield has come from mines situated in the town, at Brookville and at Sandy Creek. The reefs occupied comparatively small but persistent fissures in granite. The sulphide ores, being complex, were not amenable to normal battery treatment and this somewhat retarded development. Payable ore was obtained to a depth of 215m, but only a few of the many reefs were worked below 120m. The Ravenswood reefs are considered to be far from worked out, although the fact remains that the ‘cream’ of the reefs has gone and a great deal of capital would be required to reopen and develop the old mines to a stage of production and to provide suitable treatment plant.

The main lodes, comprising quartz-sulphide ore-bodies in fissures in the Ravenswood Granodiorite Complex, were situated in the town area and at Sandy Creek. The Ravenswood field included a number of outside centres, each of which had its own village, around which were grouped several mines. Except perhaps for Brookville, none of these centres was a large producer. They include Kirk, Four Mile, Donnybrook, One Mile (or Totley, mainly silver), Trieste, and Hillsborough (or Eight Mile).

The lodes at Ravenswood itself trend in two principal directions; some trend between north-north-west and north-north-east and dip to the east, and others between north-east and east and dip to the south. The north-trending lodes are more important and numerous. The lodes do not form a network, but rather several groups of north-trending lodes are separated from each other by a few east-trending lodes.

Sandy Creek

At Sandy Creek, a few miles southeast of Ravenswood, the lodes again trend in two directions. The more important lodes dip south-west, the less important north-west. In many of the outlying centres the lodes generally have a north to north-westerly or an east to east-north-easterly trend. Payable ore was obtained to a depth of 700 feet, but only a few of the many lodes were worked below 400 feet. The highly refractory sulphide ores were not amenable to normal battery treatment and this retarded early development. The primary minerals included native gold, galena, chalcopyrite, sphalerite, pyrite, quartz, and possibly calcite.

Mount Wright

At Mount Wright, deposits occur in a hydro-thermally altered breccia pipe (Cur). The breccia consists mainly of biotite granite, but it also contains pieces of fine-grained volcanics or dyke rocks. The lode consists of an ill defined zone irregularly impregnated with pyrite and sphalerite, with traces of copper and arsenic. Siderite also occurs in both auriferous and non-auriferous sections. Production figures are incomplete, but approximately 1,300 fine ounces of gold were produced. Small quantities of gold have also been worked from deep leads at the base of Tertiary sediments forming Little Red Bluff, and the Puzzler Walls.

Other small reefs have been worked at outside centres such as the Kirk, Rochford and Hillsborough, and may still hold interest for the prospector or small syndicate. At Mount Wright, 10km north-west of Ravenswood, a slightly shattered and mineralized zone in granite has been open-cut to over 30m for low average gold values, and boring has shown that there may be further limited reserves. The somewhat similar “Welcome” lode at Sala Siding has been proved by boring to offer little prospect for further development.

Other gold occurrences

Other gold occurrences in the Ravenswood Granodiorite Complex occur south-east, south, and south-west of Charters Towers. None was a big producer, but among the more important were Broughton, Rishton, Dreghorn, St Pauls, Lighthouse, Windsor, and Southern Cross. Many are described by Marks.

A little gold has been produced from the Old Homestead diggings (which is within the Mount Pleasant Goldfield and sometimes referred to as the Toomba Goldfield), 11 to 19km north of Homestead and from the Big Hit mine. In both cases the mineralization is probably related to the Lolworth Igneous Complex.

Gold has also been found in the Cape River Beds and Mount Windsor Volcanics: gold was worked at the New Homestead diggings south-east of Thalanga siding late last century; at Liontown in the early 1900s; and at the Highway mine in the 1950s. Numerous old shallow workings, about which little is known, occur between Brittania homestead and the Gregory Developmental Road. They are the result of gold mining and prospecting activities earlier in the twentieth century; some may be the result of work during the depression years of the 1930s. None of the deposits in the Cape River Beds has been a large producer.

Ravenswood also forms the centre for prospecting operations in an area to the south which carries gold. Lolworth is 50km north-west of Pentland. Initial development took place many years ago, and numerous gold-bearing veins have since been worked. The most important deposits, however, have been of the greisen pipe type, notably the Mons Meg and the Midas. Exploration has shown hat there is no prospect for further production below the 60m level in the Mons Meg. There is a wide extent of auriferous country between here and the Cape River, extending also south-easterly through Mount Stewart and the Homestead field to Allandale. (Further information on these fields can be found in the next section under the “Hughenden Area”).

HUGHENDEN AREA - Overview

Mode of Occurrence and Origin

In the BMR Report Number 126, it reports that there are several kinds of primary mineralization in the Hughenden Geological map area:

(a) quartz veins associated with porphyry dykes into which they merge in places (Upper Cape and Mt Remarkable);

(b) greisen and pegmatitic quartz veins (Lolworth diggings);

(d) simple quartz veins (Mt Remarkable, Mt Clearview, and Brilliant Brumby);

(e) and erratic pods in barren rock (Pentland district).

It is almost certain that more than one period of mineralization is represented in the area. The primary structural control seems to have been fractures trending between north and north-east.

Government Geologist, Richard Daintree emphasized that the mineralization at the Upper Cape Mine and the Mount Remarkable Mine is often closely associated with acid porphyry dykes or ‘elvans’. (The word ‘elvan’ is used by authors on the geology ‘of Cornwall, for quartz-feldspar porphyry and felsite dykes which intrude the Cornish granites and surrounding slates), for example near Gorge Creek (Upper Cape district), where the quartz veins appeared to him to be almost ‘a continuation to the surface of the elvan veins themselves’. Rands describes Greens Specimen reef at the Upper Cape as a kaolinized feldspathic rock resembling quartzite, which is transected by auriferous quartz veinlets. Unfortunately such dykes were not sighted in the Gorge Creek area during the 1963 regional survey, and their affinities and relationships are unknown.

However, throughout north-east Queensland they appear to be characteristic of a high level of intrusion, and are commonly associated with epizonal granites. Therefore the acid porphyry dykes at Gorge Creek and Mount Remarkable are unlikely to be related to the Lolworth Igneous Complex, which is not a high-level intrusion, and whose associated dykes have granitic, pegmatitic, and aplitic textures. The difference in association is epitomized by the contrast between the Lolworth Igneous Complex, on the one hand, and the epizonal subvolcanic Mundic Igneous Complex, on the other, which intrudes it. Clearly it is important that any future study of the gold mineralization in the Cape River district must solve the problem of the identity, age, and relationships of the porphyry dykes.

Morton reports that the Mons Meg lode at Lolworth diggings appears to post-date a diorite dyke cutting across the granite of the Lolworth Igneous Complex. It is thought that this dyke and the mineralization are more likely to be related to the Mundic Igneous Complex than to the Lolworth Igneous Complex. On the air-photographs a prominent swarm of intermediate to basic dykes of the Mundic Igneous Complex can be seen trending north-west through the mineralized area. Such dykes are nowhere known to be related to the Lolworth Igneous Complex. Dykes of porphyritic hornblende andesite, metasomatized and slightly mineralized in places, are described petrographically in CSIRO Mineragraphic Report No, 211. It seems reasonable to relate these dykes to the dyke swarm of the Mundic Igneous Complex that transects the Lolworth diggings.

Alluvial gold derived directly from coarse disseminations in a porphyry dyke was recorded by Daintree near Mount Remarkable or Mount Specimen. It is possible that this has a genetic connection with the gold occurring in veins of quartz and felsite in volcanics (Puv) south-west of Golden Mount.

The most likely source of the mineralization at Mount Emu Plains and Mount Clearview are respectively the Dumbano Granite and the Lolworth Igneous Complex. Although dykes are mentioned are in the reports on Mount Clearview, their relationship with the mineralization is not clear.

The source of the gold-bearing veins in the Pentland district and at Mount Davenport is unknown, Hands (Report of 1891, p 2) reports that the Union reef is ‘crossed’ (presumably cut) by dykes of coarse muscovite (?) granite, which suggests that these reefs may be related to or older than the Lolworth Igneous Complex.

Many creeks, which were often used as reference points in the old reports, such as Sandy Creek, Reedy Creek, and Specimen Creek, are not marked on the RASC topographic map which was used as a base for the geological map. However, in most cases they can be identified by perusing the air-photographs while reading the descriptions in the reports. In view of the occurrence of coarse waterworn alluvial gold at the base of the Campaspe Beds in the Cape River Deep Lead, and the similar occurrence at Chinaman's Gully, the Campaspe Beds should be regarded as a prospective target if any further exploration for gold is carried out in the area.

On geological grounds it seems reasonable to suggest the existence of potentially auriferous deep leads beneath the basalt which all but encircles the Lolworth diggings. The possibility of fossil gold placers occurring in the sedimentary rocks along the present north-eastern edge of the Galilee and Eromanga Basins was first pointed out by Daintree, and should also be considered in the course of further exploration.

Of metals, only gold and minor silver have been produced in commercial quantities. The discovery of alluvial and primary gold along the Cape River in 1867 heralded a long period of spasmodic prospecting which resulted in a total recorded production of nearly 55,000 oz (1,710.5 kg) of gold. In 1910 gold and minor silver-lead were discovered 18 km east of Mount Emu Plains homestead and the total recorded production of gold was 400 oz and 4,500 oz of silver.

The chief gold-producing area was the Cape River Gold and Mineral Field, which included all of the gold deposits in the geological map area south of the Lolworth Range , and also those at Mount Clearview and Mount Stewart. The field has a total recorded production of 45,000 oz (1,399.5 kg). The actual production was considerably greater, because there is no record of the quantity won by the Chinese miners, who were almost as numerous as the Europeans during the productive years of the field, and because the small production in later years was included with that from Charters Towers.

PENTLAND - Overview

Pentland is 238km by rail south-west of Townsville. In the deep lead of the Cape River a rich deposit of alluvial gold was followed southerly for nearly 6km at depths up to 30m, but generally much less. Investigation has shown that, contrary to general opinion, loss of the lead was not the cause of cessation of operations, the workings having been abandoned when the gold became scattered over a broader area downstream below a bar. The lead has never been traced to the original source of the gold.

Lower Cape Area

The most important single occurrence of gold in the Pentland or ‘Lower Cape’ district was in the basal conglomerate of the Campaspe Beds, in a strip known as the Cape River Deep Lead. Gold was also won from other deep leads, from quartz veins, and from Recent alluvium. The deposits in Recent alluvium were quickly exhausted, many of the gullies were extremely rich but the output was not recorded.

The Cape River Deep Lead consisted of auriferous conglomerate, about 30 to 50cm thick, resting on schist; the overlying finer-grained sediments were virtually barren. The lead began just south of Capeville homestead, where it was shallow, narrow, and rich. To the south it became progressively deeper, wider, and poorer. About 4km south of Capeville the grade fell off abruptly where a large aplite dyke forms a high bar in the bedrock. South of the bar, only small disconnected areas were rich enough to be mined, and the cost of sinking below a depth of 30m made further exploration prohibitive. Morton traced the lead at the surface for a further 4km, and concluded that, although rich patches are probably present, they are too small and scattered to repay exploration.

Another gold lead, evidently also in the Campaspe Beds, was worked along Sandy Creek (Chinaman’s Gully) near Cornelia homestead.

The position of the Sarah Houston (Howson), Mystery, Hayward, Hughes Leader, Just-in-time, and Big lodes is not clear, but they were probably located about 4km north-east of Pentland. The lodes, which were reported to occur in ‘granitoid schist’, trend north-east. The Golden Hill reef and the Springs reef, south-west of Pentland, were other small producers. The hand-sorted ore from the Pentland lodes yielded up to 2 oz (62.2 g) of gold per ton, and the deepest shaft was 30 m deep.

Upper Cape Area

In the Upper Cape area, workings were centred on the lower reaches of Gorge Creek, where it joins the Cape River. The deposits occur in narrow rich quartz veins near the contact between metasediments of the Cape River Beds and biotite-rich gneissic adamellite of the Ravenswood Granodiorite Complex. Most of the lodes occur in the Cape River Beds. Some were reported to originate from, or occur within, acid porphyry dykes or sills.

Alluvial gold occurred in small rich leads (Canton, Pothole, and Bluff) along Gorge Creek and in the Cape River north of Oak Vale homestead. The leads carried gold to a depth of 12m, where they died out in contact with hornblende schist bedrock. At one time consideration was given to dredging these deposits (Morton, 1933), but nothing eventuated.

The Harp of Erin and Wheel of Fortune lodes are situated 3.5 to 5km south-west of the main group, in mica schist and quartzite cut by granite dykes, but no production figures are available. Rands reports on gold workings in small veins and alluvium near the headwaters of Reedy Creek and in gullies in quartzite country to the west of Black Mount.

Mount Clearview

The auriferous lodes at Mount Clearview were discovered in 1915, but although considerable development took place, little gold was won. Work recommenced in 1933, and from then until 1938, nearly 1,700 oz (52.9kg) of gold was produced, with an average grade of about 14 dwt (21.8 grams) per ton. The gold occurred in four lodes in fine-grained gneiss and schist of the Cape River Beds. The metamorphics trend north-east, but the lodes occupy meridional fissures. Granitic dykes striking parallel with the schists are reported to occur in the area, but it is not clear from the reports whether the dykes postdate the lodes, or vice versa.

Government Geologist, William Rands described alluvial gold workings in Italian Gully, Sneak-away Gully, and others in the headwaters of Oxley Creek, but he quoted no production figures.

Considerable attention has been paid in the past to the reefs at Mount Clearview, but the necessity for transporting the ore to Lolworth for crushing then hampered development.

Mount Davenport

Mount Davenport was the centre of some lode and alluvial production. The Union and General Grant lodes were worked in mica schist. The main shaft in the Union reef was sunk to 55m, and the main shaft in the General Grant to 34m.

Mount Remarkable

Both alluvial and lode deposits were worked near Mount Specimen and Mount Remarkable. The problem of locating the workings accurately is complicated by confusion over the identity of Mount Remarkable. It seems that the hill called Mount Specimen on the 1959 RASC 1 :250 000 topographic map, which has been used as a base for the geological map accompanying the Report, was known as Mount Remarkable to the Survey geologists who reported on the area. (This Geological Map is not reproduced here. Please refer to the original report for full details).

Between Norwood and Specimen Hill, near the Balgay mine, a large amount of alluvial gold has been won from shallow ground. Many small, rich leaders occur in the locality. Specimen Creek and its tributary gullies were rich in alluvial gold.

The erratic primary gold mineralization occurred in quartz veins related to porphyry dykes. The veins occupied meridional fissures in quartzite and mica schist. The deepest shaft was 49.5m, but most were about 10m deep. The average grade of ore was 40 dwt (62.2 g) per ton, though some lodes carried up to 400 dwt (622 g) per ton.

Crushings were small, and were generally composed of picked stone. The main producing lodes were the Balgay and the Barcoo: others were the Morning Star, Governor Blackall, Lone Star, Martins, Albions, Mariners, and Commissioners. Attempts were made in the late 1930s and early 1940s to recommence mining of the Balgay lode, but the venture failed. At least some of the gold in the Mount Remarkable district appears to have occurred in quartz veinlets in the Upper Permian (?) volcanics (Puv) south-west of Golden Mount.

Mount Emu Plains

The Mount Emu Plains area, to the north of Hughenden, was worked from 1910 to 1915 and from 1939 to 1942. The mines are in the Dumbano Granite near its contact with the Cape River Beds. The granite here commonly contains muscovite instead of the more typical biotite. The ore-bodies consist of quartz veins or greisen with quartz lenses: extraction of the gold was hampered by the content of galena, pyrite, arsenopyrite, and sphalerite.

Some difficulty was experienced in treating the sulphide ore with the crushing mill available on the field and later parcels were sent to smelters.

The most important lode is the Granite Castle, which has been explored for about 400m on the surface. It consists of greisen and lenses of quartz in a well marked fissure which trends east and dips steeply to the north. It ranges up to 1.5m in width. The quartz veins, which average about 25cm wide, contain most of the gold. The lode has been worked to a depth of 30m in the Granite Castle and 27m in the Granite Castle West. Recoveries from hand-picked shipments were over 20 dwt (31.1grams) of gold per ton. A small but rich producer was the Diecan, sunk on a narrow quartz vein showing free gold. The vein was followed to a depth of 18 metres.

Lolworth Diggings

Several mines situated between Brandy and Toby Creeks were together known as the Lolworth diggings. Gold was discovered in 1926, and mining effectively ceased in 1953, although attempts are still made from time to time to reopen the mines on a small scale. There was very little alluvial production.

The deposits occur in biotite adamellite of the Lolworth Igneous Complex. The adamellite has been intruded by various dykes which, may be related to the Mundic Igneous complex. The ore-bodies were probably formed at relatively high temperatures. They consist of small veins, with greisenized aureoles, which contain pyrite, arsenopyrite, chalcopyrite, and sphalerite; greisen pipes containing small amounts of the same sulphides; and pegmatitic quartz veins. Other high-temperature minerals present in small amounts are wolframite, scheelite, molybdenite, bismuth, and tourmaline. Torbernite has also been recorded. The occurrence of gold in bournonite from the 115-foot (35m) level of the New Venture mine is described in CSIRO Mineragraphic Report No.211.

The Crystal Oak mine was the site of the original discovery. The deposit consists of a stock-work of gold and copper-bearing quartz veins. A small amount of Copper and about 350 oz (10.9kg) of gold were produced between 1928 and 1939. The grade averaged about 20 dwt (31.1g) of gold per ton from picked ore. The workings are less than 30 m deep.

The Midas mine was the biggest producer at Lolworth; 3,550 oz (110.4kg) of gold were taken from it between 1934 and 1950. The ore occurs in a pipe of greisenized granite. Besides gold, a little sphalerite and chalcopyrite are present. The main shaft is 40m deep, and the average grade was 28 dwt (43.5g) per ton. The mineragraphy of some specimens of ore from the Midas mine is described in CSIRO Mineragraphic Report No.205.

At the Sunrise and Big Shine mines the ore occurs in small pegmatitic quartz veins occupying fissures in the granite. The Sunrise produced about 800 oz (24.9kg) and the Big Shine 250 oz (7.8kg). The ore averaged about 100 dwt (155.5g) per ton at the Sunrise, and 40 dwt (62.2 g) at the Big Shine.

The Mons Meg lode was discovered in 1934 and was worked until 1953. The ore-body is a greisen pipe containing gold and small amounts of galena, sphalerite, and chalcopyrite. The ore averaged 17 dwt (26.4g) per ton, and was enriched where the ore body intersected a diorite dyke (Mundic Igneous Complex?), which probably acted as a barrier to the ore-bearing fluids. The main shaft is 59m deep, and the total production was 2,700 oz (84kg).

It is recorded that the Lolworth Diggings area produced approximately 8,363 oz (260 kg) of gold.

Mount Stewart Area

No geological work has been done on most of the mines near Mount Stewart, and their locations are not known, but over 60 of them are mentioned in Wardens’ and other reports but it is likely that at least some of them are related to the Mundic Igneous Complex, which forms Mount Stewart itself.

Most of the lodes on and around Mount Stewart trend north to north-east, and dip to the east, and their average thickness is about 30cm. The maximum recorded depth of workings is 34m at the Surprise. The distribution of the gold appears to have been erratic. The total recorded production is 1,650 oz (51.3kg) of gold from 2,300 tons of ore.

The Brilliant Brumby mine was worked from time to time and lies to the west of the main group. The main lode trends at 350° and is almost vertical; there are several smaller parallel lodes. The average thickness of the veins is about 30 cm and the maximum thickness about 1 metre. The outcrop can be traced for 300 m, and surface workings extend for over 200 m; the main workings, which are at the northern end, are about 120 m long and up to 24 m deep. The total recorded production is 790 oz (24.6 kg) from 950 tons of ore.

EINASLEIGH AREA

Kidston – The Oaks Goldfield

Kidston (42km south of Einasleigh) also called “The Oaks.” About 75,000 oz of gold have been won from the Oaks Goldfield, 1.6km west of Kidston. Gold was discovered here in 1907 and mined till 1942. The most comprehensive description of the Oaks Goldfield is that by Marks in his geological report. The gold is found in quartz veins and altered and crushed zones of the Forsayth Granite. Large bodies of low-grade gold ore have subsequently been worked by open-cuts, chiefly at Wises Knob.

More recent attention has been towards working of groups of small leaders. Operations were facilitated by the existence of a State battery now out of commission. Kidston forms a centre for outlying areas to the south, at which wolfram, scheelite and gold-copper have been worked. Less important occurrences of gold are apparently associated with quartz porphyry in Balcooma Creek.

GlLBERTON AREA

Woolgar Goldfield

The Woolgar Goldfield covers an area of 2,850 km², (129km north of Richmond). A number of gold reefs were worked with encouraging results many years ago. Following a revival in the thirties there has been subsequent intermittent small-scale mining, with local battery facilities. Most of the mines are contained within an area of 1,000 km² near the Woolgar River on the south-western edge of the Gregory Range in the southern part of the Gilberton Geological 1:250 000 Sheet area. The most comprehensive description of the field was provided by Saint-Smith.

The gold reefs are in granite and Archaean (?) metamorphics, both of which are intruded by dolerite (‘diorite’) and pegmatite dykes. Saint-Smith described the reefs as occupying ‘shrinkage lines along the margins of pegmatitic granite dykes’. Reefs also occur in shears within the dolerite (amphibolite) dykes. The reefs ranged from 3 to 210 m in length (average 60m); they were 0.6m wide and worked to an average depth of 24m, about the depth of the water table. The reefs generally dipped from 80° to 85°. Some of the gold ore contained lead, copper, and manganese minerals.

The main production was obtained from the Woolgar Goldfield between 1880 and 1887, when 567kg (15,000 oz) of gold was won, including 150kg (4,000 oz) of alluvial gold. Production declined after this period, and up to the time of Saint-Smith’s inspection in 1922 only 113kg (3,000 oz) of gold, averaging 50 grams/tonne (1.33 oz/tonne), were produced. The main producing mines were the Perseverance-Try Again, Soapspar, and Mowbray. The Soapspar and Redjacket mines were the only mines working in 1958.

Percyville Goldfield

The Percyville Goldfield is situated on the Percy River in the northern part of the Gilberton Geological Sheet area. The gold occurs in reefs near the contact of Precambrian metamorphics with granite, both of which have been intruded by pegmatite and rhyolite dykes. Ball (1915) described the lodes as generally siliceous. The gold reefs average 0.6m in width and some are nearly 0.5km long.

Most workings do not penetrate below the oxidized zone, which is probably 30-45m deep; the deepest workings extended to 152m in the Union Mine. The gold ore contained appreciable amounts of lead, silver, zinc, and copper; one assay at the 30m level of the Homeward Bound Mines was 560 grams/tonne (15½ oz per tonne) Silver, 45 grams/tonne (1¼ oz per ton) Gold, 13% Lead, 2% Copper.

Total production from 1912 to 1917 on the Percyville Goldfield was 2,080 tonnes of ore, which yielded 150kg (3,950 oz) gold, 400kg (10,334 oz) silver, and 90 tonnes copper; 13 tonnes of lead were won in 1912. The largest production from any one mine was 105kg (2,800 oz) of gold from the Union Mine. The primary ore averaged 20 to 25 percent copper and 220 to 260 grams/tonne (6 to 7 oz per tonne) of gold, with exceptional small rich patches containing 3,700 grams/tonne (100 oz/tonne) gold.

Gold has also been mined from quartz reefs in the Proterozoic granite at Mount Hogan in the headwaters of Granite Creek in the north-east. No information is available on the size of the reefs. Jack and Etheridge recorded production of 170 kg (4,500 oz) of gold averaging 65 grams/tonne (1¾ oz per ton) from 1885 to 1890.

Gold averaging 75 to 110 grams/tonne (2 to 3 oz per ton) was mined at Mount Moran, 3km north of Ortona copper mine near the northern boundary of the Geological Sheet area. Gold was obtained from quartz veins in weathered and leached dolerite dykes between depths of 15m and 90m, below a cover of Cretaceous sediments. The Mount Moran Mine should not be confused with Mount Moran, a prominent peak in the Mount Hogan goldfield.

CLONCURRY AREA

Gold first attracted prospectors to the district, but the deposits, though rich in some cases were not extensive and the mineable gold was soon worked out. A partial revival of gold mining took place in the depression years of the 1930's, but since that time the amount of gold produced has been negligible.

The principal centres of gold-mining were Top Camp (alluvial), south of Cloncurry, Soldier’s Cap (reef) area, south-east of Cloncurry and Gilded Rose (reef), also south-east of Cloncurry, Bower Bird / Sunday Gully area and Doughboy Creek (alluvial), south-west of Kajabbi.

Gold was also won from the (?) Upper Proterozoic Quamby Conglomerate, near Mount Quamby. This gold is probably of hydrothermal origin, but may be detrital. Alluvial gold has been won from each of the localities referred to above and also from an area 14.4km west-south-west of Cloncurry.

The prospects of finding payable gold deposits are not as favourable as for base metals. However, areas both south and east of Cloncurry are considered most favourable for further gold prospecting.

The total recorded production of gold from the Cloncurry Mineral Field to the end of 1954 is 102,043 ounces. Of this amount over 60,000 ounces was obtained from the ores of the main copper mines outside the Cloncurry Geological Sheet area. It includes 3,277 ounces of gold obtained from copper ores (average grade of recovery 0.48 dwt/ton). In the period 1931-1942 whilst approximately 3,061 ounces of gold were obtained from 3,021 tons of gold ore, other than copper-gold ore; this represents 90% of the total production from such ore for the whole of the field.

The discovery of the unusual Silver Phantom deposit near Kuridala in 1953 shows that it is possible for new deposits to be found by careful prospecting even in areas which were thought to have been thoroughly examined. Parcels of high-grade ore consisting of native silver and cerargyrite have been obtained from the deposit.

The total recorded production of gold is less than 57kg, practically all of it as a by-product from the production of copper from the main mines. The figures for individual mines are included in the Table. Jensen has recorded gold from the Lochness area, and Rayner from Silver Ridge 64km north of Mount Cuthbert. It does not appear to be present in economic quantities or grade at either place. ‘Colours’ have been obtained from a number of places within the area of outcropping Precambrian, from both crystalline and sedimentary rocks.

May Downs

Reef gold has been worked in one area only: the May Downs deposits, near Mine Creek, north-west of Mount Isa. The total production from 242 tons was 1,003 oz.

Duchess Area

Gold has come almost entirely from copper-gold ore-bodies in this area. The few gold workings have only yielded a few tens of ounces of gold. No gold production, apart from that from the Trekelano copper mine, has been recorded for over twenty years.

Urandangi Area

A minor gold rush to the headwaters of Jayah Creek occurred when gold was reported 6 miles east of Jayah Bore, but no production appears to have been recorded.

INGHAM AREA

Some alluvial gold is found in the headwaters of Yamanie Creek and Smoko Creek; in a few of the alluvial tin deposits at Broadwater Creek; and in the deep leads at Mount Fox and Black Cow Creek. Lode gold is associated with complex sulphide ore at Rocky Creek.

INNISFAIL AREA - Overview

The recorded total production of 56,500oz of gold was obtained almost exclusively from the five goldfields shown. Alluvial deposits yielded most of the output; lode mining, though widespread, was less successful. The ore shoots in the quartz lodes were generally found to be small, irregular, widely spaced, and not very high-grade, and offer little scope for large-scale development. The deposits are located in rough terrain covered with dense rain-forest, and transport costs in the old days were so high that each group of workings relied on its own small stamp batteries rather than send its ore to some central treatment plant.

Of the goldfields the Russell River Field (later expanded to the Russell Extended) took first place with 47% of the total output, and has been the most intensively surveyed geologically. According to Broadhurst (1955-1958) these alluvial deposits form a number of narrow terraces along the slopes of the steep-sided valleys of the Coopooroo Creek - Wairambah Creek drainage system, and were buried by late-Cainozoic basalts. They have been exposed by re-incision during recent rejuvenation of the drainage. The gravel was worked by hydraulic sluicing from adits. Among the difficulties experienced were the lack of accessible water (notwithstanding the high rainfall), the rough terrain, the soft, decomposed ground which caved-in readily, and the fact that parts of the gravel are firmly cemented by iron hydroxides.

Other adverse conditions are the low grade and irregularity of the scattered deposits, and the thick overburden. Broadhurst in 1957 - 1958 with the help of an engineer, Garth, made thorough geological and economic investigations of the area, and came to the conclusion that the remaining reserves could not be profitably mined.

For a short period, auriferous quartz lodes were mined in the vicinity of Towalla, some 2½ miles south of the Russell River terraces. The originally reported grades of two to three ounces per ton were apparently not sufficient to counterbalance the high cost of transport and the inadequacy of the reserves, and the field was deserted from the year 1905. In the Jordan Creek Gold Field, many of the thin quartz leaders in which the gold is contained are manganiferous, and a little pyrite and arsenopyrite are also present. The geological map shows the workings in the Wyreema group arranged in a north-north-east belt; the north-east lodes here are apparently arranged en echelon, and may have been produced as tension cracks caused by a dextral shear couple in a north-north-east zone.

Some prospecting has been carried out on a few deep leads under the basalt covering the granite, but the gold values are not high, and tunnels need much timbering on account of the soft ground. Production from the Mount Peter Field was exclusively from about half a dozen irregular quartz lodes trending north-east and east-south-east across the regional strike of the enclosing Barron River Metamorphics. Values of 4½ oz per ton were reported from some of the sheets, though the average recovery grade of the field was 1oz 18 dwt per ton.

The Mulgrave River field is the oldest in the Innisfail Sheet area. Both alluvial gold and lode gold were won, but lode mining was never successful.

Alluvial deposits of pre-basalt age and similar to those of the Russell River Field occur at the eastern edge of the basalt-covered Atherton Tableland, 12.8km east of Peeramon. They contain at least three levels of ‘wash’ and the basalt cover is thin in places, or even stripped off locally.

It appears that little systematic geological work has been done in this area, but C.W. Ball believed that the ‘wash’ forms an almost continuous sheet underneath its basalt cover. Last in the order of discovered fields, and least successful, were the Bartle Frere workings situated some 7 miles west of Babinda in Barron River Metamorphics at the foot of Mount Bartle Frere, between the Bartle Frere and Bellenden Ker mountains.

Mount Mascotte

Outside the goldfield areas described, a number of scattered localities have been prospected. At Mount Mascotte, about 4km south of Yungaburra, gold was mined at times from a quartz lode in a small inlier of chiastolite schist amidst Atherton Basalt. Assay values ranged from a few pennyweights to a few ounces per ton.

Russell River

The Russell River Goldfield, also known as Russell Terraces was later expanded to: Russell River Extended in 1887 and is situated at the headwaters of the Russell River, about 10 miles east-south-east of Malanda in the Coopooroo Creek - Wairambah Creek area.

Lodes were mined at Towalla, 16km south east of Malanda in the buried alluvial deposits in late-Cainozoic terraces along sides of steep valleys, exposed by rejuvenation.

Auriferous (gold-bearing) basal gravel beds overlain by up to 20 feet of sand, silt, and clay, undercover of 40 - 100 feet of basalt. Very fine-grained gold, associated with cassiterite (tin). The workings were named: Astronomer, Marvel and Lady Olive.

Some north-west quartz reefs, were generally less than 1 foot thick, dipping steeply to vertical in decomposed Barron River Metamorphics. The gold recovery grade was 2 to 3 oz/ton, but shoots very small. This goldfield was deserted after 1905.

Tinaroo

Low-grade quartz lodes were prospected, without success, at Mourilyan Harbour and Etty Bay. Small quantities of gold occur in some of the Tinaroo workings, a few kilometres west of Tinaroo Dam, but were not payable.

Culpa Creek

Alluvial gold was won from Culpa Creek, a tributary of the Tully River, between 1894 and 1905.

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