ADR has been tested over two Scottish gold systems that offered something rare — existing drill data to check against. Gairloch, in Wester Ross, is a structurally hosted gold–copper–zinc prospect; Lagalochan, in Argyll, is a copper–gold–molybdenum porphyry whose calibrating core carries 0.11–0.15 g/t gold alongside the copper. Gold in both is carried by sulphide, so ADR was used to read the sulphide system — a pathfinder to the mineralisation, not a grade meter. Calibrated against a known hole at each site, the ADR response separated sulphide-bearing ground from barren (including a correctly reported true negative), reproduced a known shallow zone, and — at both sites — flagged a deeper target below where the drill had reached.
Seeing sulphides before the drill
Two 2020 Atomic Dielectric Resonance surveys tested one question over Scottish ground: can sulphide zones be located from surface — and confirmed against the drill?
Schematic — validated vs candidate at depth
How to read this case study
Every finding below is tagged with the evidence tier it actually earns — not the tier a marketing page might wish for. This is VEXRAD’s four-tier standard, applied consistently across every survey we publish.
Confirmed against independent ground truth — here, logged drill core and assay grades.
Expected from the physics of the ADR response, consistent with the data but not independently proven here.
A real anomaly worth drilling — a target, not a result. Not yet tested by the drill.
A negative that matched reality: no signal where drilling found nothing. A true negative is a credibility asset.
Can disseminated and structural sulphides be read from surface?
Sulphide ore bodies are the target of most base- and precious-metal exploration, yet they are expensive to chase blind. Drilling is slow, costly and destructive, and a grass-roots programme can spend heavily before it learns whether a deeper target even exists.
Atomic Dielectric Resonance (ADR) directs stacked, coherent radio-frequency pulses into the ground and reads the returning energy and frequency signature to build a virtual borehole — a depth log acquired from the surface, without drilling.
In 2020 two Scottish projects gave us something rare: sites with existing drill data to test against. One a disseminated copper porphyry, the other a structurally hosted gold-copper-zinc system. Both let us hold the ADR interpretation up against known geology and grade — the only honest way to prove a remote method.
The fieldwork and analysis were carried out under Adrok. The ADR technology, methods and intellectual property are now carried forward by VEXRAD, which continues to develop them.
Lagalochan copper porphyry
Argyll, Scotland · disseminated Cu–Au–Mo porphyry · 3 ADR scans (H1 / H2 / H3)
Can the signature of disseminated copper sulphides be extracted from an ADR scan — and separated from the host rock around it?
The set-up
Lagalochan is a brecciated, hydrothermally altered felsic intrusive: host porphyry in a sericite-altered groundmass carrying disseminated sulphides, cut by red-feldspar porphyry. The rock is highly variable at the centimetre-to-metre scale, so the team treated the background as a single altered intrusive and looked for the sulphide signal against that noise.
Three scans were sited over drill holes of deliberately decreasing sulphide content — H1 over proven copper in the top 300m, H2 marginal to the sulphide core, and H3 where drilling found no sulphides in the top 250m. That gave a direct, calibrated comparison between sulphide-bearing and barren ground.
The method
Two independent lines of evidence were combined: relative energy response down each virtual borehole, and the 5–10 MHz frequency band. An experiment removed the background signal to isolate the sulphide response, and a 20-point running average was used to separate significant frequency peaks from noise.
Calibrating drill intercepts
| LD13-1 | 166m @ 0.18% Cu + 0.13 g/t Au |
| LD13-1A | 173m @ 0.23% Cu + 0.11 g/t Au |
| LD13-1A | 19m @ 0.26% Cu + 0.15 g/t Au |
| LD84-13 | 17m @ 0.07% Cu + 17 ppm Mo |
Sulphide-bearing separated cleanly from barren
Energy response ran strong at H1, moderate at H2 and absent at H3 — matching the drilling. Low 5–10 MHz values coincided with the high-grade copper intervals in the calibrating core, while non-sulphide core showed near-zero response.
H3 read empty where the ground is empty
In the top 250m at H3, where drilling found no sulphides, the scan returned no copper signal. A correctly reported true negative — the control that makes the positives credible.
Possible undrilled sulphides deeper in H3
Once corrected against the running average, H3 showed a frequency response suggesting minor sulphides at roughly 300m — below where the hole was drilled. A target for testing, not a proven intercept.
Energy tracks sulphide presence, with depth scatter
Energy peaks sat close to the copper intercepts but offset in depth — about 20m below peak grade at H1, about 30m above the projected intercept at H2. The method flags presence reliably here; exact depth needs care.
Gairloch gold–copper–zinc
Wester Ross, NW Scotland · structurally hosted sulphides · 3 ADR scans · Weighted Sulphide Correlation Criteria (WSCC)
The ground had been drilled — but only shallow, stopping at the first zone. Was there more sulphide at depth that earlier work never looked for?
The set-up
Gairloch had a known shallow mineralised zone from historic drilling, and nothing tested below it. That made it an ideal two-part test: first confirm the ADR could find the zone that was already known, then look deeper than any drill had gone.
The method
The scans were interpreted with Weighted Sulphide Correlation Criteria (WSCC) — a scheme that weights and combines the ADR energy and frequency-harmonic correlation criteria into a single sulphide-likelihood classification down the virtual borehole. WSCC indicates where sulphide is likely to be present; it does not estimate grade.
Three scans were run across the prospect, tied to an outcrop and prior drill control at the shallow zone.
What WSCC does — and doesn’t — claim
| Reports | Likelihood of sulphide presence with depth |
| Weights | ADR energy + frequency-harmonic criteria, combined |
| Does not | Estimate grade, tonnage or economic value |
The known shallow zone was located correctly
WSCC placed the shallow mineralised zone where prior shallow drilling already knew it to be. The method reproduced the answer the drill had proven — the necessary first test before trusting it deeper.
A deeper prospect at 330–350m below site 2
Below the depth earlier drilling reached, the scans flagged a further sulphide target at 330–350m. It is undrilled — a prospect to test, surfaced by reading deeper than the historic programme did.
Same physics extends past the drilled interval
Having matched the WSCC response to the confirmed shallow zone, the same criteria were applied to the deeper section. The extrapolation is consistent with the calibrated response, and defines the target above.
Calibrated against the drill, ADR finds sulphide — and points deeper
It separates sulphide from barren
At both sites, given at least one known hole to calibrate on, the ADR response distinguished sulphide-bearing ground from barren ground — including a correctly reported true negative at Lagalochan.
It sees below prior drilling
Both surveys surfaced a candidate target deeper than the existing drill data — minor sulphides near 300m at Lagalochan, and a 330–350m prospect at Gairloch — the kind of deeper look a surface method is meant to add.
Where this sits honestly
Both were proof-of-concept surveys, and both leaned on prior drilling. The strength of the result comes from that calibration: with a known hole to tune against, ADR discriminated sulphide reliably. Without one, the frequency criteria that worked at Lagalochan are tuned to its uniform felsic host and are not assumed to transfer to different geology unchanged.
The outputs are sulphide-presence indicators and drill targets — not grade estimates, not resource statements. Energy-peak depths carried some scatter against the true intercepts. These are the real limits, and reporting them is the point of the four-tier framework above.
The team clearly fingerprinted the mineralisation and found a way to identify subsurface sulphide zones from ground level. We’re now in discussions for further test surveys on our other properties.Gavin Ingo, CGeol · Managing Director, GreenOre Gold · Gairloch trial, October 2020