Open Ground - Basket Swamp — Bonanza Silver in 1898. Never Drilled Below 45 m
Updated: 7 days ago
Basket Swamp is a historic high-grade silver mine in northern NSW that produced bonanza-grade ore from 1888 to 1910 and was open-cut mined in the 1970s–80s — yet the lode itself has never been properly drilled. The structure can be traced for at least 450 metres at surface, but only 50–100 metres of it has ever seen a drill hole, and nothing has been tested below about 45 metres depth. The only drilling ever done on the prospect — six shallow scout holes in 1995–96 — was judged against the wrong deposit model and walked away from, and no one has drilled the lode since. Even the government's own geologist, re-sampling the veins in 2000, recorded bonanza silver (1,190 g/t) after the ground had lapsed — and still nobody came back.
That miss had a district-wide cause: through the 1980s and 1990s the entire Tenterfield region was explored under a single lens — bulk, low-grade, disseminated Timbarra-style gold — by the companies that built the short-lived Timbarra heap-leach mine. A sulphide-rich polymetallic silver lode simply wasn't what anyone was scoring against. And Basket Swamp isn't a lone shaft: it anchors a granite-hosted silver–gold field that the Geological Survey of NSW mapped in 2000 and then described as having "virtually been ignored by modern exploration." What's left in the open file is a coherent silver–lead–zinc–copper system, confirmed by the 1996 operator's own laboratory work and by government sampling four years later, in a deposit class (Rivertree, Webbs, Conrad — same granite province) that is under active ASX exploration today and typically extends hundreds of metres below the depths tested here.
No resource exists at Basket Swamp, and the conservative case — that the high grade was confined to small, mined-out surface pods — remains open. The point is that for a modest, staged cost, a partner gets the first genuine test of a 130-year-old bonanza silver producer, at 2026 metal prices no previous holder ever saw.
The miss, precisely
The grade isn't still available because nobody looked — it's available because the one test ever run couldn't have found it. Six shallow, widely-spaced percussion holes sampled the halo to ~45 m; none was positioned to hit a plunging high-grade shoot, the drilling method smears narrow veins, and the results were scored against a single benchmark under the wrong deposit model, with the class's speciality-metal tail never assayed in any drill sample. The 1996 programme answered a question about the halo — the shoots at depth were never asked. Four years later the government's own sample of the veins ran 1,190 g/t silver; it has sat in the open file ever since.
The Counter Argument
The bear case is real and not yet retired. The only drilling ever done confirmed the structure but returned halo-grade silver, not bonanza grade — and every high-grade figure on record (the 1898 ore, the 9,190 g/t dump chip, the government's 1,190 g/t vein) is a selective surface or stockpile sample. Native silver with silver chloride points to supergene enrichment, so the richest material may have been shallow, oxidised and largely mined out, with lower primary grades at depth. No JORC resource exists, the historic collars and assays are unverified, and it remains possible the high grade sat in small pods that are now gone.
Is the Juice Worth the Squeeze?
We accept that case — and it is precisely why the test is cheap and the asymmetry favourable. The conservative scenario can be closed or advanced for a few thousand dollars of desktop work and re-assays before a single hole is drilled, with two oriented diamond holes then answering the depth question definitively; spend is staged and gated at every step, so the downside is bounded. Against that capped cost sits a 130-year bonanza silver producer, confirmed as polymetallic silver by two independent parties (the 1996 operator and the 2000 government geologist), that exited on economics and the wrong model — never on geology — with corridor and tin upside no prior holder valued at 2026 prices. For a JV partner, that is a small, capped outlay for the first genuine test of a system that has never properly had one.
Source Document Quotes
1. The original explorer confirmed the bonanza grade is real — with his own sample.
"One sample of this material collected by the writer and analysed by ALS Brisbane returned 9190 ppm silver and 11.0 ppm gold … This grade of 287 oz per tonne of silver is similar to that mined in 1898." — P.W. English, P.W. English & Associates, 1996 (DIGS R00002143, GS1996/324)
2. And the government geologist independently confirmed it four years later, after the ground was dropped.
"Assay G00/425 of pyritic quartz veins returned 1190 g/t Ag … 337 ppm Sb … 100 ppm Sn and 0.99 g/t Au." — R.E. Brown, Geological Survey of NSW, 2001 (GS2001/087, occurrence NB0023)
3. Why it's still open — the drilling confirmed the structure, but was judged only on grade.
"The results obtained in the drilling program while confirming the existence of the lode zone at depth failed to produce the high grade silver mineralisation that had been mined in recent years." — P.W. English, 1996 (R00002143)
4. The high grade was never lost geologically — it was lost in bulk-shipping handling.
"It appears that the recent mining operation was not able to separate the high grade lode material from the altered host rock which would have lowered the overall grade … payments were not profitable enough to continue mining." — P.W. English, 1996 (R00002143)
5. The independent petrologist described the silver mineralogy directly — and flagged it as an unusual style.
"This style of base metal-silver mineralisation associated with granitic rocks is unusual in the southern part of the New England Orogen." — P.M. Ashley, University of New England, 1996 (petrological report in R00002143)
6. The government's own geochemistry ties it to a known silver field — not to disseminated gold.
"Its high silver and anomalous antimony and tin show great similarity with the geochemical characteristics of Rivertree mineralisation." — Brown, Henley & Stroud, GSNSW, 2001 (GS2001/087, Vol 1, on the Basket Swamp lode NB23)
7. And the government flagged the whole field as overlooked.
"The Boonoo Boonoo – Basket Swamp area has virtually been ignored by modern exploration." — Brown, Henley & Stroud, GSNSW, 2001 (GS2001/087, Vol 1)
8. Mapped silver lodes north of the workings remain untested and unlocated.
"A silver lode was illustrated here on a map by Hoskins (1912). A search of the area failed to locate any workings or mineralisation." — R.E. Brown, GSNSW, 2001 (GS2001/087, occurrences NB0045/46)
Exploration history
1888–1910 — Moors; Broughton; Baker; Colvin (successive holders) · Target: native-silver lode (Ag) · Objective: direct mining of the high-grade lode · Work: underground and surface workings across four production periods; the 1898 campaign treated 17 t of ore for 3,659 oz silver, and the 1888 Annual Report records gold with silver chlorides and sulphides · Departure: small-scale hand mining; the field's underground workings were hampered by very wet ground — a water problem, not a grade problem.
1966 — Frances Creek Iron Mining Corporation (EL 97) · Target: regional multi-commodity reconnaissance · Objective: district-scale stream-sediment screening · Work: stream sampling around the Basket Swamp area (with limited tin and base-metal determinations) · Departure: regional program; the lode itself was never sampled or assayed for silver.
Late 1970s–80s — mining-title holders · Target: direct-smelting silver ore · Objective: open-cut mining with ore trucked for smelting at Port Kembla · Work: the open cut that defines the prospect today (recorded by the government as just 70 × 20 m) · Departure: unprofitable — high-grade lode diluted by altered host rock with no reliable grade control. An economic exit, not a geological one.
1987 — L. Rosetti · Target: the silver lode · Work: mapping and sampling (recorded in the government occurrence register) · Departure: not documented; no drilling.
1991–92 — Homestake / Saracen / Timbarra Mines (Timbarra tenements) · Target: Timbarra-style disseminated gold · Objective: regional gold reconnaissance across the surrounding district · Work: mapping, geochemistry and augering in the district; stream-sediment and rock-chip sampling passing near the prospect, assayed for gold with minor pathfinders · Departure: low gold — the program was never designed to test a silver lode.
1993 — Danamore (Coverdale tenement) · Target: silver in stockpiled lode material · Objective: confirm the historic grades · Work: rock-chip sampling of dumps and stockpiles · Departure: none — bonanza silver confirmed and a licence application followed.
1995 — M H Coverdale JV Pacific Arc Exploration (EL 4845) · Target: locate the lode under cover · Objective: define drill targets · Work: gridding, costeaning; located the lode and a 15 m alteration zone · Departure: none — advanced to drilling.
1995–96 — Pacific Arc / Slade Drilling (EL 4845) · Target: continuity of bonanza-grade silver at depth · Objective: test for a repeat of the historic grades · Work: six scout RC holes plus a pre-collar, 307 m total — the only drilling ever done on the prospect · Departure: relinquishment recommended on low silver assays, judged against that single benchmark under the district's disseminated-gold paradigm. The polymetallic result was never followed up. A model-driven exit.
1997–99 — Auralia Resources / Ross Mining · Target: district gold · Work: geochemistry, geophysics and remote sensing across the surrounding district, looking for Timbarra-style mineralisation · Departure: reconnaissance-level and gold-focused; the silver lode was not drilled.
2000 — Geological Survey of NSW (metallogenic mapping) · Target: none — government field program · Work: the state's own geologists mapped the Basket Swamp workings and the wider Boonoo Boonoo–Basket Swamp silver–gold field, measured the structure (strike 022°, dip 85° west), sampled the veins (1,190 g/t Ag, 0.99 g/t Au, with strongly anomalous antimony, arsenic and tin), and recorded the field as "virtually ignored by modern exploration" · Departure: not an explorer — the result was published into the open file (GS2001/087) and never followed up by anyone.
Why the grade is still available
Every party that sampled the lode found silver — including the government. The exits are documented as economic (mining dilution) or model-driven (wrong benchmark) — never as "the system isn't there." Three specific failures preserved the opportunity: the 1996 programme judged a polymetallic silver system against a disseminated gold model — the same model the whole district was chasing; the speciality-metal tail is almost entirely untested — no drill sample has ever been assayed for tin, tungsten or indium, and the single tin determination that exists — a government grab sample from 2000 — ran a strongly anomalous 100 ppm Sn and was never followed up; and the shallow scout holes sampled the alteration halo, not the high-grade shoots, which remain untested at depth.
The grades the system has produced
Result | Why it matters |
1898 production: 17 t treated for 3,659 oz Ag — ≈ 6,690 g/t (215 oz/t) silver as recorded (the 2001 government compilation records total production of ≈ 3,330 oz, and average early-mining grades of ≈ 6,084 g/t Ag with 1.15 g/t Au) | A government production record, not an assay claim. Proof the system generates bonanza grade. All recorded figures are reported. |
Government assay G00/425 (2000, GSNSW field sampling): 1,190 g/t Ag + 0.99 g/t Au, with Sb 337 ppm, As 1,020 ppm, Pb 502 ppm, Cu 235 ppm, Zn 152 ppm and Sn 100 ppm | The state's own geologist re-sampled the veins four years after relinquishment and confirmed bonanza polymetallic silver — independent government verification that has sat unused in the open file for 25 years (Brown, Henley & Stroud 2001, GS2001/087). |
Rock chip BB10 (1993, ore stockpile): 9,190 g/t Ag + 11.0 g/t Au (laboratory certificate) | Independently confirms the historic tenor a century later; native silver (± ?dyscrasite) verified under the microscope. Shows gold rides with the silver. A second stockpile sample (BB9) ran 2,300 g/t Ag. |
Drill hole BPD6, 38–39 m: 39–40 ppm Ag, 0.13–0.14 g/t Au, with elevated Pb–Zn | The most reliable drill result — reproduced almost exactly across two independent sample splits. Proves the drilled halo is mineralised and polymetallic. |
Drill hole BPD3, 47–48 m: 58–80 ppm Ag, 888–1,060 ppm Zn (range across two splits) | The deepest mineralised intercept — a logged silver-bearing vein at the very bottom of the deepest hole. The system was still there when the drilling stopped. |
Drill values are single-metre halo samples — vectors toward the untested shoots, not resource grades. Surface and vein samples are selective by nature. No JORC (2012) resource, reserve or exploration target exists; historical results are from GSNSW open-file records and have not been verified by a Competent Person for public reporting.
Geological setting
The prospect sits in the granite country of the southern New England Orogen near Tenterfield, hosted in the Stanthorpe Monzogranite. Mineralisation follows a steep structure measured by government geologists at strike 022°, dipping 85° west. The Geological Survey of NSW records the lode as 450 m long and 15–20 m wide — a quartz–sericite altered zone carrying a high-grade silver lode — against an open cut of only 70 × 20 m and drilling that reached about 45 m. The government classifies the deposit as a granite-hosted Ag–As (Au, Pb, Sb, Zn, Sn, Cu) vein system and, on its own geochemistry (high silver with anomalous antimony and tin), ties it directly to the Rivertree polymetallic silver field on the same map sheet — the same broad class as Webbs and Conrad, under active ASX exploration today and typically mined and drilled to several hundred metres depth. Basket Swamp has been tested to about 45.
A silver field, not a single mine
Basket Swamp is the silver anchor of a north-north-east-trending belt of granite-hosted silver–gold–polymetallic veins that the GSNSW mapped across the Boonoo Boonoo–Basket Swamp field — and then flagged as "virtually ignored by modern exploration." The context around the drilled lode matters:
About 4 km north, in the same granite, the Annie / Claverie & Nelmes mine — a separate historic working, not the drilled lode — is logged in the government's compilation of the old Annual Reports with vein-edge grades up to roughly 425 g/t gold and ~31,000 g/t silver (about 1,000 oz/t), carrying arsenopyrite and the silver-sulphosalt polybasite. It isn't part of ELA7079's drilled target, but it shows what this granite can carry.
To the south-west, the Dismal Swamp reef holds the field's other tin anomaly (116 ppm Sn) alongside 175 g/t Ag — a second, independent tin signal in the same system.
Immediately north of the workings, two further silver lodes mapped by Hoskins in 1912 (up to ~900 m north) have never been drilled or even relocated.
The GSNSW's own verdict on the field is unusually direct for a government report: an attractive target because the veins strike for hundreds of metres with comparable depth potential, historical gold and silver grades were of bonanza grade, combined vein-and-alteration widths were commonly two metres or more, poor outcrop has left many structures undiscovered — and many of the old mines closed on very wet underground conditions, not on running out of ore. The drilled lode isn't a lone occurrence; it's the tested corner of a large, under-explored mineral field.
Top three targets
The shoots at depth (primary). Diamond drilling directly beneath the historic workings to intersect the down-plunge continuation of the structures that produced the 1888–1910 and 1980s ore — the first real test of where bonanza grade actually lived. The government's mapping of this field shows the richest shoots form at dilational sites — where veins bifurcate or coplanar lodes intersect — and both the Basket Swamp lode and the Annie reef are recorded as bifurcating, giving specific geometry to aim at. Two oriented holes answer, definitively, whether high grade continues below the old mine.
The lode along strike, and the corridor. Step-out holes beneath the old northern workings, treating the existing drill intercepts as vectors — with the two 1912-mapped northern lodes, and the wider silver–gold field, as untested extensions of the trend. This converts a 450 m surface corridor into a drilled system — or bounds it.
The speciality-metal tail (no drilling required). Re-assaying the surviving historical samples for tin, tungsten and indium — never measured in any drill sample, with the government's two surface tin readings (100 ppm at Basket Swamp, 116 ppm at Dismal Swamp) as the tantalising first data points. A few thousand dollars of lab work either adds an entirely new value stream to every historical result or closes the question.
No JORC (2012) Mineral Resource, Ore Reserve or Exploration Target is declared or implied. Historical results are compiled from GSNSW open-file (DIGS) records, including GS1996/324 and GS2001/087 (Volumes 1 and 2), have not been verified by a Competent Person for public reporting, and are provided for context only. Grades quoted for the Annie / Claverie & Nelmes mine are from a separate historic occurrence about 4 km north and are not attributable to the drilled Basket Swamp lode. The granite-related polymetallic silver-lode interpretation is a working hypothesis under test; alternative interpretations, including the conservative surface-pod case, are set out in the Technical Synthesis. Earn-in terms are indicative and non-binding, subject to contract, due diligence and grant of the Exploration Licence.
