"By failing to consider modern engineered mitigation methods that would be required for an acceptable permit application, the report presents a biased and inaccurate assessment of the potential impacts of the Pebble Project. Some examples of our findings include:
- erroneous assumptions based on literature data not relevant to a modern mining scenario, such as culvert failure statistics developed from culverts that were never permitted in the first place;
- inaccurate calculations that significantly overestimate consequences of those hypothetical system failures, such as using inappropriate geometry in a dam breach analysis, that over predicts velocity and distance of sediment transport; and
- general lack of any attention to mitigation measures for all engineered systems which would be designed with appropriate safety factors, be accepted by regulators, and be designed to minimize the consequences of unlikely failure events, such as placing pipeline shutoff valves immediately before stream crossings instead of 14 km away, thereby limiting the amount of material that would escape if there were a failure."