Centennial site needs cleanup

October, 2020


Listen to Barbara Rivenes from the Sierra Club as she explains the EPA's requirements for cleaning up Centennial site and how that relates to the proposed reopening of the Idaho-Maryland Mine. From a CEA Foundation virtual community meeting. Transcript below.


UPDATE: The Remediation Action Plan (RAP) for the Centennial Site is now expected to be released in the Spring of 2021.

Hi and welcome. Greetings to you all. I'm here tonight to talk on behalf of Sierra Club as well as - I'm a CEA board member.


My topic is the Centennial M1 industrial site. That is one of the two sites purchased by Rise Gold for this project. Did you all know that the state of California has over 40,000 abandoned mines? The Centennial site ranked first as the top priority abandoned mine by the EPA, because of the proximity to our communities and also because of the known contamination and physical hazards that are on the site. This Centennial site located near downtown Grass Valley off Idaho-Maryland Road near Ferguson's Plumbing.


It’s a historically toxic site that is facing EPA Superfund designation. This site is 56 acres with two-thirds of the site covered with tailings from the Idaho-Maryland Mine, which operated until 1956. Though it was much quieter during the war and afterwards, in fact it then closed in the mid 50's. There is an estimated two hundred and seventy thousand cubic yards of legacy tailings which are toxic, which have to be removed in order to use the site for new dumping or placing new mine waste.


The superfund designation has been conditionally deferred for the time being because Rise Gold signed a contract with the California Department of toxic substance controls to clean up the site. But it's important to understand that these are two completely separate projects at this time.


During the Idaho-Maryland Mine NOP process in the summer of 2020, CEA asked the county to include the cleanup in its EIR…truly because the Centennial Site is an integral part of the mine project and needs to be remediated before the rest of the project can proceed. That's an important point. We have to get it cleaned up and our leadership needs to understand that it has to be remediated.


Currently, the department of toxic substance control have just given Rise Gold a timetable of their cleanup process which suggests that it will not be until early 2021 when reclamation work can actually begin. Cleanup costs are still unknown, but even by reasonable estimates, it could be put at over two million dollars.


Centennial will have its own environmental impact report with negative deck before the actual cleanup begins. Its slated to begin this fall. That's when the process of the EIR for that particular remediation will go on and the public will have a chance to talk about it. And then by the time they get all of that finished, then the work will not be finished - they’ll work through the winter and then will not be finished until the spring.


The DTSC is not looking for the overall mine project since it's outside their scope of work at this time. However, it was brought to their attention that a very large volume of mine waste will ultimately be brought in from the Brunswick Mine Site. The Centennial site, once it's cleaned up, will actually be the recipient of 1,040,000 engineered fill, reaching a height of 30 to 70 feet above the current ground level. Bear in mind that 10 feet is the standard height for a one-story building. Therefore, we face the possibility of seeing anywhere from three stories to seven story buildings. That sort of bulk in that area.


The zoning of the site is M1, which is light industrial, which is the county zoning. Centennial site is in the Grass Valley sphere of influence for future planning. Grass Valley’s planned sphere of influence zoning is business park, keeping with the rest of the Whispering Pines Business Park and surrounding neighborhoods. Rise Gold has asked the county for a rezoning for both sites combining M1 with ME, which will allow mineral extraction (ME), which will allow processing, stockpiling of mine minerals, waste disposal, and the reclamation.


Right now, there is no ME attached to that. That is something that the county will have to approve – and Rise Gold has asked for – we'll see what happens with that. Rise Gold has not requested that Centennial be annexed to Grass Valley as part of the sphere of influence. Their project would not fit very well into the land use zoning of the Whispering Pines Business Park.


It's very important for us to realize that these are being treated like two separate projects, but they really are one project. One cannot go forward without the other. Well, Centennial could get cleaned up of course, but the mine cannot go forward. It needs a place to put all those tailings. 1,040,000 of them.


Thanks for listening. In conclusion, I’d like to take a moment to show you a quick map. Just to make it come home. The Centennial site is right up there off of Idaho Maryland Mine Road. Not far from downtown Grass Valley. Not far from the hospital. And yeah, it's a toxic site and it needs to be cleaned up. We can't depend on the approval of the mine project - the larger mine project to do that.


Thank you for listening.

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