SURFACE HILL GEM DEPOSIT GULF ROAD EMMAVILLE
 |
| Location of Surface Hill with the basalt outliers marked |
How often have you
wished you were around in the “good old days”? It must have been easy to pick
up gemstones then. Maybe.
“Australian and New
Zealand Gemstones” (1972) by Bill Myatt has this statement on page 298 in a
section about Emmaville. “The Gulf Road
is not good in rainy weather, as it crosses four creeks; the crossings,
however, are all cemented. Sixteen miles out, Bill Frappell’s Topaz Farm is on the left, where camping and fossicking
is allowed on payment of a fee, the money going to charity.” I don’t know
when this arrangement ceased, but I would guess more than 30 years ago.
The place we are talking about is correctly called Surface Hill. If you’re searching for
information, don’t get confused with the many other Surface Hills around,
especially the one on the Timbarra goldfield near Tenterfield. The name refers
to the fact that the alluvial wash there was on the surface of the ground
rather than in a creek bed or its banks. The place is about 2 km south of the
Gulf Road, between Flagstone and Little Flagstone Creeks. Both Minerama and
Emmaville Gemfest have conducted field trips there. The last I knew, it was
part of the property called “Willow Creek”, where James and Kerry West
conducted their business “The Fruit
Salad Tree Company” (multi-grafted fruit trees). I believe the property has
recently been sold.
Naturally, the old time miners were not interested in topaz.
They were after tin (cassiterite)
which was eagerly sought all over the Emmaville and Torrington districts from
1872. The cassiterite originated in fluids associated with the nearby crystallising
granite. There are literally thousands of veins, dykes and impregnations which
formed from the early Triassic Mole Granite. Some are within the granite
itself, others are in the adjacent intruded rocks, such as those at Webb’s
Silver Mine. At the Emmaville Emerald Mine, the pegmatite dykes can be traced
from the intruded rocks into the granite itself.
 |
| From TWE David. Basalt outliers marked |
The story at Surface Hill is entirely different. Here the
cassiterite is found as waterworn grains in an old stream deposit. Let me quote
TWE David (from his 1887 report on the Vegetable Creek Tin-Mining Field, DIGS
reference R00031676, page 45): “The Tertiary gravels at Surface
Hill form three outliers. At Surface Hill a flat-topped ridge of claystone is capped
by a bare oval patch of tertiary gravel. The deposit has an extent of 1 acre
and a thickness of 1 to 2 feet. The pebbles of which it is composed are
principally quartz, from 1 to 6 inches in diameter, and as smooth as eggs. A
great deal of tourmaline, as well as topazes, beryls, emeralds, and stream tin
(alluvial cassiterite ed), are mixed through these gravels, which from their
higher position appear to be older than the similar gravels underlying two neighbouring outliers of basalt. In its
lithological character, and in its stratigraphical relation to the “deep leads”
this small outlier of gravel closely resembles the tertiary pebble beds at Cope
Hardinge, near Tingha. The importance of these outliers rests not
so much on the minerals contained in them, though that has been considerable,
as on what they teach of the former wide distribution of stream tin deposits
in early tertiary time. The gravels at Scrubby Gully and Surface Hill are over
6 miles distant from one another, the former being 3,360 feet above sea level,
and the latter 2,460 feet; while those in the Ruby Hill outlier have an
altitude of 1,885 feet, and are over 25 miles distant from Scrubby Gully.”
The mention of topaz, beryl and emerald should get any
self-respecting fossicker’s heart racing. I’ve been out to Surface Hill a few
times and never failed to find topaz, though not the other minerals. I have no
doubt that this is because of the similar specific gravity of beryl to quartz: We look for topaz in the sieve centre because it is dense but forget the less
dense beryl among the quartz fragments. It is the same story at Blatherarm and
Scrubby Gully. You won’t find alluvial beryl unless you are looking for it.
David has more to say on page 164. “Beryl occurs most frequently in small waterworn round or oval prisms
from ½ to 1 ½ inch long and from 1/8 to ¼ inch thick. The localities where it
is most abundant are Surface Hill and Kangaroo Flat. The majority of specimens
are pale green, and many are colourless. The gems generally contain a number of
minute cavities, which of course detract immensely from their value. Some
specimens from Kangaroo Flat, which have been cut and polished, are valued at
about £4, the cutting and polishing having cost about £3.”
The only other major source of information on Surface Hill
I’ve been able to locate is in the Grafton-Maclean Mine Data records (DIGS
Reference R00056102). There are two
listings: Surface Hill Northwest (GR1012) and Surface Hill (GR1039). The
descriptor for both is “Sn, topaz – industrial fossil placer (fluvial)”.
 |
| The 1906 SMH report |
Surface Hill Northwest pretty well matches TWE David’s description; there is both a surface
deposit and a deep lead under a small basalt cap. A large race carried water to
work the gravel which is dated to A Bouveret in 1883. NOTE. The two dams on the
creek running south and the existing water race from the creek could date from
E Sturtridge’s work in 1906, which is not mentioned. See the Sydney Morning
Herald note for 30th June 1906 (here).
Surface Hill
proper is a deep lead deposit with workings dating from 1878. To quote: “Numerous shafts and pits on side of hill.
Wash around shafts has rounded white pebbles of quartz. Has known association
with blue topaz and alluvial cassiterite.”
What would you see if you were able to get permission to go
out there? Firstly, I suggest that you follow the water race from the creek and
see where it goes. This is Surface Hill Northwest. All the topaz and beryl
would have been discarded where the gravel was washed. The area where the
surface gravel was removed is where I picked up numerous piece of topaz in 2001
solely because of the glint of the sun from cleavage faces. Find where the deep
lead was mined.
The track continuing around the hill without crossing the
creek should go to the main Surface Hill deep lead workings. Once again, beryl
and topaz should be in any discarded gravel piles or in the gully where water
carried away the waste.
This link here will take you to the ALF thread
on Surface Hill, from which I “lifted” Wwoofa’s photograph below. |
| Field Trip to Surface Hill. Photo "Wwoofa", Australian Lapidary Forum |
https://johnsbluemountainsblog.blogspot.com/2013/12/links-to-all-blog-entries-and-relevant.html All Blue Mountains blogs and videos
All New England and other Geology blogs and videos
Limestone Caves of NSW
Song Studies. Bible studies based on hymns and songs
Shoalhaven District Geology.
No comments:
Post a Comment