Sulphide oxidation and groundwater transport of base metals at the Halfmile Lake and Restigouche Zn–Pb massive sulphide deposits, Bathurst Mining Camp, New Brunswick
Bibliographic record
Abstract
A detailed hydrogeochemical study at the undisturbed Halfmile Lake and Restigouche Zn–Pb deposits, Bathurst Mining Camp, New Brunswick, was initiated to elucidate processes controlling the oxidation of sulphide minerals, factors influencing base-metal dispersion in ground and surface waters, and to improve hydrogeochemical exploration methods. Groundwaters were collected using flow-through bailer and straddle-packer technologies; the latter of which proved to be the most effective under the fracture-flow dominated conditions. Groundwaters from the two deposits are compositionally distinct. At the Halfmile Lake deposit, groundwaters are dominated by low total dissolved solids (TDS < 250 mg l −1 ) and Ca–HCO 3 -type compositions. Groundwaters at the Restigouche deposit vary in composition from shallow Ca–HCO 3 - and Ca–SO 4 -type waters to high TDS Na–Cl-type waters. Elevated sulphate and base metal contents (up to 4200 μg l −1 Zn and 1400 μg l −1 Pb) of shallow Ca–SO 4 -type groundwaters proximal to massive sulphides indicate that the sulphides are undergoing natural oxidation. The degree to which the massive sulphides are oxidized depends on the depth of penetration of dissolved oxygen and flux rates, which are controlled by the permeability of the rocks and local hydrological gradients. Transport of metals away from massive sulphides depends on physical factors that include hydrology, groundwater flow, and the degree of connectivity between groundwater and surface water environments, as well as groundwater pH, metal adsorption and colloid mobility.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".