On March 9, 2018 a “limited breach” of the tailings dam at the North Tailings Facility of the Cadia Mine tailings impoundment occurred in New South Wales, Australia. The area of the failure is approximately 270 m across, with a back-scarp of about 100 m. The runout was about 370 m. All things considered, it could have been worse. The mine owner, Newcrest Mining Limited, has ceased mining operations while they deal with the issue, and has begun radar monitoring. No additional movement had been detected as of last week. More information can be found in the briefing given to shareholders, and in the initial press release. Image: Newcrest Mining Limited
On January 15, the National Transportation Safety Board released a safety recommendation letter report to the FHWA related to the I-35W bridge collapse in Minneapolis Minnesota that claimed the lives of 13 people and injured 145. The safety recommendations are based on the findings of an interim report from the FHWA Turner-Fairbank Highway Research Center that some gusset plates, components of the steel trusses, were undersized (not thick enough). This deficiency was confirmed to be a flaw in the design and not construction-related based on review of the original drawings from the 1960s and inspection of the wreckage. Whether this was a calculation error or a drafting error will perhaps never be known as only portions of the original design calculations were located. But the point is that it was never caught by any reviewers.
When this event first happened back on August 1, I remember being very shaken up by it. After my initial sadness for the victims of the accident, my first thought as a geotechnical engineer was: â€œwere the foundations at fault.â€ As more information came out, it quickly became evident that the failure did not have anything to do with the foundations but that it was related to the superstructure of the bridge. But this still was something that profoundly affected me. (Continuesâ€¦)
LANCASTER — Months of explosive blasting are expected to begin at the site of Center Hill Dam next week as the U.S. Army Corps of Engineers prepares to begin construction work at the aging dam in Lancaster.
"The blasting will be to excavate a platform for construction, about 40 feet wide and will look similar to a road cut through a hill," [Corps Project Manager Linda Adcock] said. "Just the nature of how we grout, and moving equipment back and forth on the current slopes, which are as much as 40 percent and greater, is just really difficult. So for these reasons, for safety, quality, the accuracy and the consistency of the drill holes are much better done from a platform, they proposed this road cut type of a platform."
The drilling is for grouting remediation of the dam foundation. Story from Herald-Citizen, Cookeville, Tennessee.