Donovans Find (Smithfield), Bridgetown-Greenbushes Shire, Western Australia, Australiai

Regional Level Types
Donovans Find (Smithfield)	- not defined -
Bridgetown-Greenbushes Shire	Shire
Western Australia	State
Australia	Country

Located 16 kilometres south-west of Bridgetown and east of Tin Fields Road. It has also been described as the Smithfield pegmatite area, containing Donovans Find. Over the past ten years, exploration for cassiterite took place, and the location was then covered in earth and rehabilitated.

Cassiterite bearing stream gravel was discovered by W. Smith and G. Gough in 1907, naming it Smithfield, and limited mining took place. The location was 'rediscovered' in 1931. Around this time cassiterite was also discovered in the area at Native Dog Gully (Ross's Find) 2 kilometres south of Donovans, Coated Tin Hill, and Willow Springs. The area was explored by Austmac Developments Ltd in 1941, F.G. Forman 1962, Westralian Oil Limited 1966, Greenbushes Tin NL 1971, and then again from 1983-1991. Further exploration work by various companies occurred in the 1990's and early 2000's. None found economic grades of tantalum and cassiterite. Shareholders should view with scepticism, any further exploration work in the area.

Cassiterite and tantalite grains are found in weathered laterised pegmatites, up to 35 metres wide, striking north north-west. The pegmatites are kaolinized albite-quartz-microcline-muscovite, intruding the Ballingup metamorphic belt. Chrysoberyl has been reported from the pegmatites (the Western Australian Museum has one specimen), but further specimen grade material of any species is yet to be seen beyond this.

The tin discovery attributed to Donovan, at what is probably the original site of Smithfield, is located at lat.34°03’S, long.] 116°01'E. The most direct access is by way of a forestry track signposted Tin Mine Road, branching southeasterly from the Brockman Highway about 18 km west of Bridgetown. At about 2.5 km from the highway, a side track named Mine Road leads to the diggings.

The main workings are in the valley of a short
creek, variously called Gough Gully or Donovan
Creek, flowing east-southeasterly into a south-flowing
tributary of the Donnelly River. The workings consist
of shafts, pits and small cuts on a north-striking line
of pegmatite veins, together with alluvial workings in
the floor and sides of the valley. The largest opening is
a sluice cut located where the creek cuts the line of
pegmatites. About 120m downstream from the cut
are the remains of a circular puddling trough. Some
70m further east, on the northern slope of the valley,
are the foundations of a plant erected in about 1951. A
hole some 15 m in diameter and 6 to 7 m deep immediately
below the plant was probably excavated as a
sump, although it is close to the site of an old shaft
shown on Leevers’ (1942) plan.

shafts were inaccessible, and much of the information
given below is taken from the reports of Talbot
(1907), Blatchford (1932), Leevers (1942), Brisbane
(1951) and Forman (1963).

Pegmatite deposits: Although the line of pegmatites
trends at about 360’ individual veins seen in the cuts
strike either northeast or northwest. Forman concluded
that they were small pipes or lenses, and not a
continuous body extending between clusters of shafts.
The first pegmatite worked (Blatchford, 1932)
was located beneath the present sluice cut, underlying
the rich alluvial deposits being worked at the time.
The pegmatite was reported to be 1.5 to 1.8m wide,
and was worked from two or more shafts over a
length of 24 m.

Mainly shallow diggings extend northwards from
the sluice cut for a total distance of 130111, with small
clusters of deeper (4 or 5 m) shafts, centred at 35 m,
50m, and 95 m from the cut, sunk on weathered pegmatite.
Widths and assay results of pegmatites in
some of the shafts are given in Table 28.
About 80 m south of the sluice cut, a narrow pegmatite
vein striking 030’ is exposed in surface workings
over a distance of 25 m. Leevers stated that drives
6 m below the surface showed the tin content to be erratic,
but wherever the vein did carry cassiterite, it was
60 to 90cm wide and averaged about 0.09 per cent
SnO2.
The most southerly group of shafts is about 425 m
south of the creek, alongside a track connecting Tin
Mine Road and the southern continuation of Mine
Road. It consists of four shafts sunk on two en echelon
pegmatites striking at 3W0. The larger vein was
traced for 30 m in a number of pits and one shaft. The
second vein, which is a little further north, was tested
by three shafts each at least 6 or 7m deep. One of
these openings is probably Payne’s shaft, which, according
to Leevers, was originally 12 m deep with 11 m
of drives from its foot.

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References