The numbers just do not add up. As I read the many sites on the web, I learn that British Columbia has about thirty operating mines. The BC government has about $172 million in closure bonds. Say about five or six million a mine. That seems grossly inadequate to me. I have just finished estimating closure of one mine and it came to nearly $60 million. Does this mean BC should have $1.7 billion in closure bonds? Here are some observations from various websites that may help you ponder this issue. (more…)
Archive for the ‘Policy and procedure’ Category
While we in BC have been preoccupied by the Mt Polley situation, yet another tailings failure has occurred. This time in Mexico. That brings the number of failures this year to three: Duke Energy, Mt Polley, and Cananea. Just the right number if the probability of failure is one in five thousand. (more…)
Posted in About the news, British Columbia, consulting, due dilligence, Law (Mining), Mining history, safety, Tailings, tagged apegbc, canadian dam safety association, dam safety, guielines, MAC, Mining association of canada, mt polley on August 20, 2014 | 10 Comments »
The five pictures in this posting, were taken (by me) at the Getty Center in Los Angeles. This place is surely a testament to genius and attention to detail.
Yesterday I was asked if Canadian guidelines are adequate to deal with the Mt Polley situation. More specifically, the questions continued: if the current Canadian guidelines regarding tailings dam safety had been implemented, would the failure have been avoided. Before I answer these questions, let us first take a look at the guidelines that are out there. (more…)
The most confident fellow in the meeting was the specialist in permitting from Toronto. He was old, like me, and in total command of his subject. He reminded us: “California is both the most difficult and yet the easiest state in the Union in which to permit a mine. It is easy because the process is simple: fill in the boxes, check off the items of the checklist, and it is done. It is the most difficult because you need to have done the work to ensure the right answer to fill in the boxes. If you do not have a comprehensive, well-thought-out, and defensive plan, you cannot fill in the boxes, complete the checklist, and get the regulators to say OK.” (more…)
I am told that yesterday’s posting was hard to read. So rather than write tonight, let me simply post some pictures I took from a public road of tailings facilities closed by the Peruvian regulators. Not sure how long the gabion baskets will last.
Posted in consulting, Geosynthetics, Geotechnical, Heap leach, Reclamation, Tailings, Waste Rock, tagged cover, erosion, geosynthetic, mine closure, Reclamation, rock cover, slope stability on July 2, 2014 | Leave a Comment »
The exterior surface of most tailings, waste rock, and heap leach facilities include:
- A top deck which is the flatter surface that forms the top surface of the facility. This is usually sloped at between one and five percent, primarily to promote runoff.
- The sideslopes which are easily covered if they are inclined at about five horizontal to one vertical (5H:1V) but which in practice may be as steep as 1.4H:1V.
Covers on the top deck are less subject to erosion, slope instability, and soil creep than covers on sideslopes. Thus different covers may be appropriate at the same facility on the top deck as compared to the sideslopes. Here are a few idle thoughts on sideslope covers for mine waste facilities. (more…)