this phd thesis from 2006 has a whole section on Bungonia:...

this phd thesis from 2006 has a whole section on Bungonia: http://researchdirect.westernsydney.edu.au/islandora/object/uws:2409
The exploration summary from Tharsis Mining in 2013 is also useful:

"5. PREVIOUS EXPLORATION
A literature review of previous work in the Bungonia area was completed. The focus of
Tharsis' exploration in the Bungonia area is the manganiferous cobalt ± nickel/copper
deposits in the area (Figure 3). These deposits have been known since the late 19th
century, and since that time a number of companies have evaluated them.
Mcintyre Mines Limited / Vam Limited / ASARCO (1969-1972)

The first attempt at systematic evaluation was conducted by Mcintyre Mines Limited in 1969
in Authorities to Prospect 2975 and 3315. Vam Limited took over exploration of the
manganese deposits in 1969 and was granted EL 279. The program on EL 279 was then
continued by ASARCO when Vam went into receivership. ASARCO discontinued the
manganese programme and concentrated on basemetal evaluation.

Mcintyre Mines does not appear to have conducted any detailed exploration in the area and
Vam apparently concentrated its activities in the vicinity of the mineral occurrence site
referred to as Mine No. 294 on the Goulburn 1:250,000 Metallogenic sheet. Vam's
activities included costeaning, and although detailed results of this work have not been
sighted, it is believed that Vam calculated resource estimates on the basis of this work.
The costeans have subsequently been infilled. In total, the area was believed to host nearsurface
deposits amounting to approximately 200,000 tonnes grading 0.4% cobalt.

North Broken Hill Limited (1980-1981)
North Broken Hill Limited were granted EL 1315 in February, 1980 and commenced
exploration for large tonnage manganiferous wad deposits. Extensions to the
manganiferous grits were traced to the southwest and Exploration Licences 1351 and 1477
were subsequently granted to cover possible extensions. Although the company failed to
locate any significant new reserves, with total possible reserves quoted as 40,226 tonnes
grading 0.40% cobalt, they did note that the material was very amenable to simple
metallurgical treatment.
No significant manganiferous wad occurrences were found in EL 1351. In all, 766 rock chip
samples were taken and assayed for copper, lead, zinc, silver. nickel, cobalt and
manganese.
Insufficient manganese-cobalt reserves, limited signs of "true" gossan, lack of IP anomalies
and limited anomalous gold assays downgraded the area and the licences were
subsequently relinquished.

Red Anchor Resources (1991-1996)
Red Anchor initially identified a large number of manganese wad deposits containing
potentially economic grades of cobalt, nickel and copper in Tertiary grits occur within a
narrow zone striking NNE and extending from Bogungra Creek to Bungonia. a distance of
some 18 kilometres.
The high grades present were probably due to a form of scavenging. The high levels of
contained metals were thought to have been derived from a local metal source within this
May 2013 - 6 - EL7919 Bungonia
NNE- trending corridor, since most manganiferous deposits outside this corridor had low
manganese-cobalt ratios. The source of the metals in the wad was not conclusively
proven, but is probably of local derivation with the metals released into the groundwater
during weathering. The low cobalt content of the Budjong deposits precluded this area as a
source. The overlying basalts of Tertiary age were anomalously high in cobalt, and may be
the source of at least this element.
Red Anchor concluded that although the manganese wad-cobalt-nickel-copper deposits
contain metal values which may be extracted economically, previous drilling programmes
encountered problems, but did demonstrate the erratic nature of the mineralization and the
low tonnage problem. A limited exploration programme was considered warranted if:
- significant potential tonnages have been overlooked (considered unlikely)
- the mineralization is the redistributed component of basemetal deposits in the
bedrock.

In summary, the manganese wad deposits carrying high cobalt-nickel-copper values are
mainly restricted to the northern portion of the Cullulla-Bungonia trend between Bogungra
Creek and Bungonia in the Northwestern Zone, and a local source of these metals is
inferred. Previous exploration has down-graded the chances of finding large tonnages of
cobaltiferous wad, however the source of the cobalt and nickel had not been adequately
defined. The source may be the Tertiary basalts, but it may also be from intrusive igneous
phases comagmatic with the basalts or perhaps of Upper Palaeozoic age and now covered
by Tertiary and Quaternary deposits. A number of the drillholes which tested the
manganese wad deposits penetrated into bedrock, however no bedrock samples appear to
have been assayed for basemetals. A scout geophysical testing programme was
considered warranted over a few selected deposits which occur in interesting structural
locations.

Cobalt Resources / Stuart Metals (1994-1996)
As a result of Stuart Metals' field reconnaissance, rock-chip sampling and more detailed
geological mapping, it has been shown that these mineralised grit occurrences are more
widespread than previously recognised within the licence area.
In particular, a north-north-east trending, possibly structurally controlled zone in the
southern portion of the licence hosts numerous occurrences which return rock-chip assays
of up to 1.8% cobalt. Locally, mineralised grit exposures in the above southern zone
appear to be thicker (up to 5 metres) and to have greater areal extent than occurrences
elsewhere in the region.
Stuart Metals completed a total of 77 Rotary Air Blast (RAB) reconnaissance drilling,
totalling 621 metres of drilling at five prospects. This work has confirmed the presence of
mineralised grit horizons with thicknesses of up to 6 metres. Several occurrences appear
to be lag or remnant deposits with limited economic potential; other occurrences appear to
have been preserved under resistant laterite (and possibly basalt) cappings.
It was recommended that future exploration employ a more powerful drilling rig capable of
investigating mineralised horizons preserved beneath resistant cappings. Stuart Metals
was not able to give this work priority in relation to its other projects, and recommended that
title to the area be relinquished.

The previous exploration referred to above is generally consistent in two respect:-
a. Manganese-cobalt occurrences in the area appear to be of limited lateral extent with
somewhat limited tonnage potential.
b. Rock-chip samples which contain anomalous cobalt typically assay in the range 0.1-
1.5% cobalt, with an average value of approximately 0.4-0.5% cobalt."

Tharsis was after nickel, and didn't find much, so relinquished the tenement.

The gamble here is whether CAZ can extend the resource from Kt to Mt. I would read these reports on NSW DIGS very carefully. Central West Gold 2009 is also useful. Every explorer has called for more drilling to prove extensions but without doing it themselves.

I'm also curious as to whether the lithium in the lithiophorite can be won alongside the cobalt. When North Broken Hill did their acid leaching mets lithium wasn't really a concern. Having cobalt+lithium in one project could be an edge.