FlagstoneReport
Does the work support the claim?
Assessment of an NI 43-101 technical report

Copper Creek Project

Pinal County, Arizona, USA (~70 km northeast of Tucson)
Study stage
PEA · Preliminary Economic Assessment
Published
May 3, 2023
Prepared by
Ausenco Engineering USA South Inc., with SRK Consulting (U.S.) Inc., SRK Consulting (Canada) Inc., and Call & Nicholas Inc., for Faraday Copper Corp.
Source
PEA_Copper_Creek_2023.pdf
Study-level anchor — not scored
PEA Preliminary Economic Assessment

Every judgment below is measured against what a PEA is expected to demonstrate — not an absolute bar.

Detected from the filing

Title page and Section 1.1: 'NI 43-101 Technical Report and Preliminary Economic Assessment (PEA)'. Section 1.7 states no PFS has been completed and there are no mineral reserves. Capital estimate stated as AACE Class 5, +50%/-30%, PEA-level. Standard PEA cautionary language regarding inferred resources is included.

Peer Benchmarks

2 of the report's figures are benchmarked against PEA peers — shown as the expected range for the stage and where this project sits within it.

2 at the edge
Cu Recovery – Flotation89.7%

Sits at the edge of the expected range for PEA.

79.2%91%
Typical PEA range 83.6%–88.35% · full peer span 79.2%–91%
Capex Intensity – Open Pit$73 /t·yr

Sits at the edge of the expected range for PEA.

$24$114
Typical PEA range $43–$62 · full peer span $24–$114
Internal consistency
Recovery claim vs. testwork89.7 → 95.4%

The claimed 89.7% carried into the economics is backed by the 95.4% testwork result.

Not benchmarked at PEA stage
Cu Recovery – Leach75%

No PEA peer set for this metric — not benchmarked.

Opex/t milled$13.01 /t

No PEA peer set for this metric — not benchmarked.

Grind Size P80200 µm

No PEA peer set for this metric — not benchmarked.

Sitting outside the expected range is context to investigate, not a verdict — a project can legitimately sit apart for geological or metallurgical reasons. These positions inform the reader; on their own they do not decide the grade.

Flagstone Score

We grade two crucial dimensions, then determine a final score from them.

AExceeds

Methods robustness

Does the disclosed work match what the study stage demands?

Judged against the PEA column of Part 3, the disclosed work surpasses stage expectations on multiple axes. (1) Variability composite count: PEA expects 1–3; the 2023 ALS program used 9 variability samples plus 3 composites, on top of METCON's 14-composite 2012 variability program — far beyond the stage minimum. (2) Locked-cycle testing is NOT required at PEA yet two LCTs were run (Sulphide Master Composite: 95.4% Cu, 71.7% Mo to a 30.0% Cu / 0.077% Mo concentrate; Blend Composite: 83.8% Cu), and the LCT circuit recovery was used to validate the cleaner recovery factor carried into the forecast. (3) Mineralogy→recovery linkage is only 'preferred' at PEA but is fully realised here: QEMSCAN copper deportment by mineral form for every sample, PMA liberation on both master composites, and — critically — the transitional Cu recovery equation is built bottom-up from per-mineral recovery factors (chalcopyrite/bornite 95%, chalcocite/covellite 79.9%, malachite/azurite 52.8%, Cu-bearing iron oxides 0%) weighted by a LOM mineral distribution. That is FS-grade geometallurgical reasoning at PEA stage. (4) Flowsheet is deposit-specific and justified by measured data: coarse primary grind (200–225 µm) supported by liberation and rougher kinetics; NaHS sulphidization added specifically to recover malachite/azurite in transitional ore; no regrind on transitional material to limit cleaner losses; comminution measured on 8–9 samples supports SABC sizing (Axb 38, BMWi ~14 kWh/t). (5) Deleterious elements tested against penalty thresholds with an arsenic feed-grade threshold derived (70 g/t) and a blending mitigation. Per Rule 4C, the absence of pilot testing and the assumed 90% Cu-Mo separation recovery are stage-normal at PEA and are NOT counted as gaps — the QP nonetheless discloses the assumption and recommends confirmatory separation testwork. Genuine stage-relevant thinness exists (only 4 of 8 open pit sources sampled; no underground/porphyry-specific flotation samples in the 2023 program; transitional LCT not run; oxide leach forecast rests on 1995 column tests from a single breccia), and these are honestly disclosed by the QP — but at PEA they do not offset work that clearly reaches PFS rigor. The strong, domained, mineralogy-driven recovery framework supports the top letter.

  • Report omissionaffects the gradeOnly 4 of the 8 open pit mine sources were represented by 2023 metallurgical samples (OP3, OP6, OP7, OP8 not sampled), acknowledged as due to limited Phase 1 core availability. Stage-appropriate at PEA but limits spatial coverage.
  • Report omissionaffects the gradeNo locked-cycle test on the Transitional Master Composite; transitional closed-circuit performance is inferred from low open-circuit 2nd/3rd cleaner tail losses. Not required at PEA.
  • Report omissionaffects the gradeOxide heap leach recovery (75%) rests entirely on 1995 MSRDI bottle-roll and column tests on three composites from a single breccia (Old Reliable), with no modern leach testwork; the QP recommends additional acid leach testwork on more oxide samples representative of the various breccia formations.
  • Report omissionaffects the gradeThe 2023 flotation program targeted open pit material; no dedicated flotation variability samples from the deeper Keel/American Eagle porphyry block cave resource, which supplies 211 Mt (the majority of LOM mill feed). Historic MSRDI/METCON work covered some Keel/American Eagle composites.
  • Report omissionaffects the gradeMolybdenum head grades in the 2023 samples were near or below detection in rougher tails, so Mo recovery equations may carry analytical error (explicitly disclosed by the QP).
Metallurgical framework quality
Considers operating conditions beyond head gradeyes
Metallurgical domains defined, each with its own recoveryyes
Range of lab results explained by the frameworkyes

Explained vs. unexplained The framework explains the great majority of the observed lab recovery range. Sulphide rougher recovery (91.9–99.3% across tests) is explicitly shown NOT to trend with head grade, so a constant 97.3% average is adopted rather than a spurious curve — and the low outliers are attributed to specific reagent/pH conditions (MET-05 at natural pH 7.4 gave 91.9%, improving to 95.7% with PAX+lime; MET-01 at 225 µm gave 92.6%, rising to 99.3% at 180 µm with lime and PAX), i.e. scatter is explained by operating conditions rather than left as noise. Transitional rougher recovery spans 20.7–82.6%, an enormous range, and the framework accounts for it structurally: the 20.7% test was at natural pH with no lime/NaHS; recovery rises progressively with lime to pH 9 and NaHS sulphidization (58.9→61.3→71.7→73.4%); and the residual sample-to-sample spread is explained by measured copper deportment (MET-09, 66.6% chalcopyrite → 82.6%; MET-07, 47.8% chalcocite/covellite plus 16.8% Cu-bearing iron oxides → 56.3%), with 0% recovery assigned to non-floatable Cu-bearing iron oxides. What remains unexplained: the Blend composite LCT at 83.8% Cu is not explicitly reconciled against the 94.4%/73.7% domain forecasts; the oxide leach domain has only three 1995 composites and a single flat 75% number; and no domain relationship is derived for the deeper porphyry/block cave feed, which is simply treated as sulphide.

What the QP flagged in Section 13
  • riskTransitional material recoveriesSection 13.5: 'Transitional mineralization is currently believed to represent favourable metallurgical performance, however further test work is deemed to be beneficial to understanding and de-risking recoveries in the future.' Section 13.2.4 notes a locked cycle test was not run on the Transitional Master Composite because 'it was uncertain whether this composite adequately represented average transitional material.' Section 1.16.6 recommends further Cu:S ratio and soluble copper assessment plus flotation testwork on Phase II samples to confirm transitional recoveries. The transitional recovery equation (73.7% at 0.40% Cu head) rests on open-circuit tests and a modelled mineral-assemblage weighting whose representativeness the QP itself flags as uncertain. Transitional material is ~20% of open pit tonnes.
  • limitationCopper-molybdenum separationSection 13.2.4: 'The test program did not include copper-molybdenum separation due to the limitation of the metallurgical testing scope.' Section 1.16.6: 'Molybdenum recoveries reported herein are based on process assumptions observed for similar materials ran under similar conditions and simulations. Cu-Mo separation test work on representative materials is limited.' Historical MSRDI and METCON 2008 separation attempts were inconclusive due to insufficient feed mass; METCON 2012 achieved ~30% Mo concentrates in open circuit. The 90% Cu-Mo separation circuit recovery is an assumption. Per PEA-stage norms this is standard and defensible practice for a low-grade byproduct, and the QP discloses it and recommends confirmatory testwork; Mo contributes a modest share of revenue (1.4 Mlb/a average).
  • limitationLimited drill core available for metallurgical testingSection 13.2.1: 'The availability of samples suitable for metallurgical testing were somewhat limited due to the scale of the phase 1 drilling program, therefore not all sources indicated in the mine plan were represented.' Section 1.16.6 repeats this and recommends additional core be made available. MET-08 and MET-09 were received as coarse-crushed assay rejects, limiting comminution testing. Spatial representativeness of the 2023 program is partial (4 of 8 open pit sources); recovery forecasts extrapolate to unsampled sources.
  • recommendationOxide/acid leaching testworkSection 13.4.1 states the 75% recovery forecast is 'conservative' and is made 'due to the limited leaching test work data available for Copper Creek oxide materials.' Section 1.16.6 recommends additional acid leach testwork on more oxide samples representative of the various breccia formations, assessment of acid-soluble copper correlated to mineralogy, grind size optimization and verification of acid consumption. The heap leach recovery is based on 1995 column tests on one breccia; the QP frames 75% as conservative relative to the 83% measured on the high-oxide composite, which mitigates the thin basis.
  • limitationMolybdenum analytical uncertaintySection 13.3.4: 'the molybdenum levels in these samples was quite low, resulting in molybdenum contents in the rougher tails streams that were below the laboratory detection limits. For this reason, molybdenum recoveries may be subject to analysis errors.' Mo recovery equations carry disclosed analytical uncertainty; the QP surfaces rather than conceals this.
  • riskNon-floatable copper species and arsenicSection 13.5: 'the only processing factors or deleterious elements that could affect potential economic extraction are the presence of non-flotatble copper mineral species in transition material and arsenic bearing copper sulphides within hypogene material at depth... these contents are both relatively low and would not have a significant effect on potential economic extraction.' Section 13.2.5 derives a 70 g/t As feed threshold for penalty-level concentrate and proposes blending. Both risks are identified, quantified against penalty limits, and given a mitigation; not left as an open exposure at PEA level.
  • opportunityCoarse particle flotationSection 13.5 and 1.16.6: 'there may still be opportunity to apply coarser primary grinds to improve tailings dewatering performance'; CPF could mitigate throughput constraints associated with tailings dewatering and dry stacking, save grinding energy and incrementally improve recoveries. PMA showed only a low proportion of Cu sulphides in low-exposure coarse grains, so conventional flotation is suitable, but coarser than 300 µm would change that. Upside identified with a measured mineralogical basis and an explicit caveat on the grind limit beyond which it degrades.
  • limitationBlend composite locked-cycle sub-sampling errorSection 13.2.4 discloses that in the Blend composite LCT, tails streams were retained in slurry form and slurry cuts were extracted for assay and mass balance, 'which introduces a sub-sampling error not associated with typical dried and prepared test products.' The 83.8% Cu recovery on the Blend composite carries a disclosed accuracy caveat; the report does not carry this figure forward as the design recovery.
  • opportunityTransition tails and historic tailings recoverySection 1.16.6 recommends investigating dewatering and acid leaching of fines reporting to transitional flotation tails with Cu recovered as cathode via SX/EW, and surveying/assaying two historic on-site tailings impoundments for reprocessing potential. Identified upside not included in the economics.
  • recommendationGeometallurgical model developmentSection 1.16.4 recommends Faraday continue collection of solubility data, copper mineral species reports and related recovery data 'to enable development of a robust geometallurgical model as the Project advances. Further solubility testing will define metallurgical material type boundaries and determine variability for grade in recovery within these areas.' The QP acknowledges the current geometallurgical framework is a first-pass and that material-type boundaries need firmer definition before PFS.
AStrong

Result representativity

Are the reported numbers trustworthy as reported?

Against the Part 4 signals the disclosure is unusually complete for a PEA. VARIABILITY BEHIND AVERAGES: full test-by-test tables are published (Tables 13-8 and 13-9) giving every rougher test's grind, pH, reagent dosages, calculated head, tail assay and mass/Cu/Mo/S recovery — the reader can see the 91.9–99.3% sulphide range and the 20.7–82.6% transitional range that sit behind the headline numbers, plus head assays and QEMSCAN deportment for all nine samples, comminution results per sample, and both LCT results. Historical METCON and MSRDI ranges (77–93% cleaner Cu; column leach 69.6–83.3%) are also given as ranges, not averages. POOR-PERFORMING TESTS ARE SHOWN, NOT SUPPRESSED: the 20.7% transitional test, the 56.3% MET-07 result, the 83.8% Blend LCT (below the 94.4% design figure), and the inconclusive historical Cu-Mo separation attempts are all reported. This is the opposite of best-result selection. MINERALOGY GROUNDING: recovery is explicitly explained by ore mineralogy — per-mineral recovery factors in Table 13-13, 0% assigned to Cu-bearing iron oxides, liberation measured at 71%/47%, and the arsenic risk quantified against a 70 g/t feed threshold. BASIS DISCLOSURE: the 94.4% figure is fully traceable (97.3% average rougher x 97% cleaner, cross-checked to 97.7% LCT circuit recovery); the 75% leach figure is expressly labelled 'conservative' against an 83% column result and tied to a 50 mm crush size; the 90% Cu-Mo separation factor is openly identified as an assumption rather than a measurement; and the Mo equations carry a stated analytical-error caveat because tails were below detection. INTERNAL CONSISTENCY: the economic-table 89.7% LOM mill Cu recovery is a legitimate blend of the 94.4% sulphide and grade-dependent transitional recoveries across the schedule, and sits below both the 94.4% design figure and the 95.4% LCT measurement — the claim does not outrun the testwork. Two minor reservations exist: the resource-estimate CuEq recoveries (92/85/60%) differ from the process design criteria (94.4/73.7/75%) without explicit reconciliation in the provided text, and the Summary states 'over 94.0% copper from sulphide material and 74.0% from transition' as 'results from flotation testing' when these are in fact forecast values rather than raw test averages. Neither is material enough to move the letter off A given the exceptional transparency elsewhere; the reader is given every underlying data point needed to check the numbers. Per Rule 7, no adjustment is made here for any claimed-versus-measured recovery gap.

  • Report omissionaffects the gradeThe mineral resource CuEq calculation uses recoveries of 92% (sulphide), 85% (transitional) and 60% (oxide), which differ materially from the process design criteria of 94.4%, 73.7% and 75% used in the economics; the provided sections do not reconcile the two sets.
  • Report omissionaffects the gradeSection 1.15 describes 'over 94.0% copper from sulphide material and 74.0% copper from transition materials' as 'results from flotation testing' when these are forecast/derived values (the transitional figure in particular is a modelled equation output, not a measured average).
  • Report omissionaffects the gradeThe Blend Composite locked-cycle result of 83.8% Cu is not explicitly reconciled against the 94.4%/73.7% domain-weighted forecast in the provided text.
  • Data gapnot in the extracted text — does not affect the gradeDetailed year-by-year recovery build-up reconciling the 89.7% LOM blended mill Cu recovery in Table 1-13 to the domain equations would sit in the economic analysis section (Section 22), which was not provided.
Flagstone Score
A-

Work exceeds what the stage requires; claims well supported.

How the grade was reached

The letter is a deterministic roll-up of the two dimension grades and the peer flags — the same inputs always produce the same grade.

  1. Recovery: claimed 89.7% (carried into economics) vs measured 95.4% -> gap -5.7 pts
  2. Gap not material -> no representativity penalty
  3. Weakest link: methods=A, representativity=A -> take the lower = A
  4. Flag penalty: amber Cu Recovery - Flotation (%) [recovery] -1; amber Capex Intensity - Open Pit ($/annual t ore) [capex] -0.5 (reduced: cost metric)
  5. Weighted penalty = -1.5 notches, capped at -3 and floored to whole notches -> -1
  6. Final grade (floored at D) = A-

METHODS — A (Exceeds). Against the PEA column of the Part 3 matrix, the disclosed testwork clears stage expectations on multiple axes simultaneously, which is the Part 7.1 'A' anchor. PEA expects 1–3 variability composites; the 2023 ALS program used 9 variability samples plus 3 master composites, layered on METCON's 14-composite 2012 variability program and two earlier MSRDI campaigns. Locked-cycle testing is expressly not required at PEA, yet two LCTs were run and one was used to validate the cleaner recovery factor carried into the design. Mineralogy→recovery linkage is only 'preferred' at PEA but is delivered at a level normally seen at FS: QEMSCAN copper deportment on every sample, PMA liberation on both master composites, and a transitional recovery equation built bottom-up from per-mineral recovery factors with zero recovery assigned to non-floatable Cu-bearing iron oxides. The flowsheet is deposit-specific and data-justified (coarse 200–225 µm grind supported by liberation and kinetics; NaHS sulphidization introduced specifically to float malachite/azurite; no transitional regrind to limit cleaner losses; SABC sized from 8–9 measured comminution samples). Per Rule 4C, the absence of pilot work and the assumed 90% Cu-Mo separation recovery are stage-normal at PEA and were not counted against the report — the QP discloses both and recommends confirmatory work. The metallurgical framework assessment reinforces the A: three domains with distinct recovery treatments, operating conditions genuinely built in (grind, regrind, reagent regime, pH, pulp density, concentrate grade), and the lab scatter largely explained by domain mineralogy and reagent conditions rather than fitted through with a naive head-grade curve — the report in fact explicitly rejects a head-grade relationship for sulphide Cu because the data do not support one. Real thinness remains (only 4 of 8 pit sources sampled, no 2023 flotation samples from the porphyry block-cave feed that supplies most LOM tonnes, no transitional LCT, oxide leach resting on 1995 column tests from a single breccia), and the QP flags all of it — but at PEA stage these do not offset work reaching PFS rigor. RESULTS — A (Strong). Against Part 7.2, the headline figures are traceable on every signal. Full test-by-test tables expose the 91.9–99.3% sulphide and 20.7–82.6% transitional rougher ranges behind the averages; poor results are published rather than suppressed (the 20.7% transitional test, MET-07 at 56.3%, the Blend LCT at 83.8% below the design figure, the inconclusive historical Cu-Mo separation work); recovery is grounded in measured mineralogy; and the basis of each number is stated, including the derivation chain for 94.4%, the 'conservative' framing of the 75% leach recovery against an 83% column result, the explicit labelling of the 90% Cu-Mo factor as an assumption, and the disclosed analytical-error caveat on the Mo equations. Two minor reservations were noted — the unreconciled difference between the resource CuEq recoveries (92/85/60%) and the process design criteria (94.4/73.7/75%), and the Summary's loose description of forecast recoveries as 'results from flotation testing' — but they are not material enough against the weight of underlying data disclosed. On the recovery extraction: the economic table carries a blended LOM mill Cu recovery of 89.7%, which is below both the 94.4% sulphide design figure and the 95.4% Sulphide Master Composite locked-cycle measurement, so the claim does not outrun the testwork. PEER POSITION (PEA bands only). The 89.7% economic-table flotation recovery falls in the [Cu Porphyry — PEA] amber band (88.8–94.4%) and sits between the PEA peer median of 87.0% and p75 of 88.8% — above median but well inside the observed peer range, and explained by a domain-weighted build-up. Heap leach recovery of 75% sits above the PEA leach peer median (72.65%) and within the peer range (66.1–79.0%). Capex intensity of roughly $73 per annual tonne ore ($798M / 11.0 Mt/a) falls in the [Cu Porphyry — PEA] open pit amber band ($62–114/t-yr), between the PEA open-pit p75 ($62.3) and max ($113.6) — noting this is a hybrid open-pit-then-block-cave project where much of the underground capex sits in the $1,859M sustaining/expansion bucket rather than initial capital, so the intensity figure understates full-life capital. Opex of $13.01/t processed sits between the PEA peer median ($8.58) and p75 ($13.01) — at the p75 mark. Grind P80 of ~200 µm sits at the PEA peer p75 (190 µm) and within the peer range (100–240 µm). Throughput of 11.0 Mt/a is below the PEA peer p25 (15.2 Mt/a) in the mill-only phase. Authoritative flags are computed separately in code.