Placer Mining Along The Fraser River, British Columbia: The Geomorphic Impact
Bibliographic record
Abstract
We investigate the geomorphic impact of 19th century placer mining along the Fraser River, British Columbia, by estimating the volume and grain-size distribution of excavated sediment, evaluating the transport potential for the sediment in the river, and discussing the relation between placer waste sediment and observed morphodynamics of the Fraser River channel. Volume-by-area regression relations applied to 456 mapped mines estimate the total volume of material excavated to be about 58x106 m3 (bulk volume). Sampling of mine scarp and mine lag sediments indicates that the discharged tailings consisted of 54% sand and finer and 46% gravel and small cobbles. Modern observation and historical narratives indicate that the channel of the Fraser between Quesnel and Laidlaw has been generally stable following placer mining. Application of a sediment transport function indicates that the river is capable of moving annually an amount of sediment comparable to the maximum loading from placer mining. By applying established relations between channel scale and sediment virtual velocity, we estimate the rate of downstream movement of the placer-waste slug to be between 1 and 6 km a-1 The predicted rates of sediment migration indicate that peak delivery of placer waste to the lower river below Laidlaw likely occurred early in the 20th century. This predicted behavior agrees well with observed aggradation on the lower river. The result emphasizes the importance of historical legacy in the appraisal of recent geomorphological processes and shows that widespread small-scale disturbance has affected the Fraser River, with the effect concentrated where the gradient of the river is reduced.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.003 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 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".