The report, commissioned by the Tsilhqot'in National Government (TNG), states clearly that Taseko Mines has not provided enough analysis or underlying data to back up its plans to use a large, productive lake as a tailings pond. The TNG commissioned the report to address what it perceived as failings in Taseko's submission to the Federal Panel.
Taseko Mines is a medium-sized metals producer based in Vancouver, and has, for nearly 15 years, worked towards developing an ore body into an open pit mine. Their plan has always included draining Fish Lake and turning it into a Tailings Storage Facility (TSF). The proposed mine is located about 200 kilometers southwest of Williams Lake, and about 20 kilometers from the First Nations community of Xeni Gwet'in (pronounced Hunee Gateen) in the Nemiah Valley.
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The proposed Prosperity Mine's ore body sits within the collective traditional territory of the Tsilhqot'in Nation. Marilyn Baptiste is Chief of the Xeni Gwet'in community. She says that her community views the whole mine proposal as unacceptable because it can destroy fish, wildlife and water for future generations.
Roger William was chief of the Xeni Gwet'in for 17 years, from 1991 to 2008, and currently serves as Lands and Stewardship Director for the TNG. In a recent interview, Mr. William said he felt validated by Stratus' report because the Tsilhqot'in people have always been concerned that contaminated groundwater would reach other lakes and rivers, possibly wiping out fish populations that include salmon, steelhead and trout.
Mr. William went on to say that Taseko Mines always told them that Fish Lake is "in its own valley and nothing will leak from the tailings pond". He believes that Taseko Mines is paying expert consultants to study the environment, but that there is a conflict of interest since the people doing the studies are paid by the mining company and the results are not independent.
In many hard rock mines, protecting the environment from water leaching from tailings piles is of paramount importance. Acid is produced on the surface of waste rocks dug out of the mine (the tailings), and the result is that both acid and metals such as arsenic and cadmium leach into the surrounding environment.
Unless held in a waterproof facility, these leachates, known as Acid Mine Drainage, can wash into surface streams and into the groundwater. In both instances they can have far reaching impacts on terrestrial and aquatic ecosystems, and can decimate fish populations. They can also lead to fish being unfit for human consumption and allow toxic metals to find their way up the food chain.
Tailings Storage Facilities work by keeping at least part of the tailings submerged in water to prevent air from forming acid on the rock surfaces. As a result, any mine tailings held in Taseko Mines' proposed TSF would require a constant supply of water to prevent the generation of acid waste.
Thus, the issue of water supply to the TSF, as well as where the water and leachate could go if it escaped the TSF, are fundamental to potential impact of the mine.
Taseko's mine proposal is currently in front of a Federal Environmental Review Panel. The Panel is reviewing Taseko's own report as well as input from other groups, including First Nations and environmental groups. In this process, Taseko is responsible for generating its own analysis of potential impacts on the environment, as well as means of mitigating impacts. Other groups have to rely on Taseko’s information for their own analysis.
The federal and provincial government attempted a joint panel for about 18 months, but the panel came out in opposition to this mine proposal and to another north of Fort Saint James. As a result, Taseko left the panel in fear it would lead to a failed application, and the provincial government followed.
The TNG found out that the BC Environmental Assessment Office (BCEAO) had decided to leave the joint panel through the newspapers. Loretta Williams is Mining Director for the Tsilhqot'in National Government, and has worked on this project since 2006. She says the BCEAO "could have had the decency to tell us directly", and that the problem with the provincial panel is that they wouldn't hear people talk. They only took written submissions, and had a track record of approving all projects put in front of them.
Stratus Consulting Report
The report commissioned by the TNG was written by Stratus Consulting Inc. of Boulder, Colorado, and was led by three prominent scientists whose specialties include hydrology, geochemistry, and the study of minerals and toxins escaping from mining facilities into the environment. The report focused on Taseko's water balance model, whether the Tailings Storage Facility would have enough water to keep the tailings submerged, and whether toxic chemicals would be likely to escape to the environment.
Rather like being between a rock and a hard place, not enough water leads to exposure of tailings and generation of acid mine waste, while too much water creates a significant likelihood of an escape from the tailings facility. The report found that Taseko Mines consistently over-represented the amount of water available to flow into the TSF, while under-representing the ways in which acid mine drainage could escape the TSF.
Furthermore, according to Stratus' report, since Taseko's does not explain its modeling methods, no one knows how they estimated the probability of water surpluses and deficits. The underlying data implies that Taseko has vastly underestimated uncertainties in the water balance, meaning that the mining company could not possibly be prepared for the effects of extreme weather events or climate change.
In terms of water flowing into the TSF, Stratus states that Taseko used a very limited and inconsistent amount of stream data to estimate the amount of water available, and ignored losses that now appear to be the result of faults and fractures where stream water runs into the bedrock to become groundwater.
In response to the Stratus report findings, Xeni Gwet'in Chief Baptiste said that it was "a disgrace and an embarrassment [for Taseko Mines] to have based their predictions on such poor data". She said it is obvious to those who live in the area that things like precipitation vary widely from year to year, and using just two years of data is unacceptable.
Chief Baptiste also said that when Taseko began this process they held community meetings and seemed committed to developing a relationship with the community, but that several years ago they abandoned this approach and are now very much “hands off”. She feels it is up to the Xeni Gwet'in and Tsilhqot'in people to protect the land and resources from this mine.
The Water Model
Stream water comes ultimately from precipitation, and Taseko's model assumes that 100 per cent of precipitation, including all rain and snow falling in the catchment area, will find its way to its streams, and so they simply converted the amount of annual precipitation data directly into stream inputs.
What they ignored in making this calculation is that, in any ecosystem, there are significant losses before precipitation can reach streams, including evaporation, sublimation, transpiration, and escape to groundwater.
Despite the crucial nature of stream data, and in spite of the fact that Taseko has been on site for fully 15 years, the mining company has collected water data for only six years, and only two of these have complete data sets for the entire year. Stratus' scientists state emphatically that this little bit of data is unsuitable for predicting the next 25 years and 100 years of exposure as required in the Environmental Assessment.
Some precipitation evaporates before it reaches a stream, and Stratus says that, since Taseko could not create a model of evaporation losses, they instead used 40 year old data from an area 250 kilometers to the southeast. Since the proposed mine site is in the immediate lee of the Coast Mountains, 250 kilometers in any direction leads on to entirely different ecosystems, terrain and climate.
Sublimation is similar to evaporation, but applies to snow which, after being intercepted and held up in the crowns of trees, turns back into vapour and escapes back into the atmosphere. Despite two years of data showing that up to 30 to 40 per cent of precipitation may be lost to sublimation, Taseko Mines made the assumption that these losses would be negligible, resulting again in the prediction of unrealistically high stream flows.
Transpiration is water that is pumped out of an ecosystem by trees and other plants and put back into the atmosphere. While transpiration can be as much as 30% of precipitation, Taseko disregards it entirely in its water model, which also leads to unrealistically high predictions of stream flows.
The ultimate consequence of less stream flow is to expose the tailings and create more acid waste, and Stratus suggests Taseko likely wished to minimize the appearance that this might occur.
Stratus states that Taseko gathered streamflow data "haphazardly and inconsistently", and that it even acknowledged that it was over-estimating streamflows in its model. Further, Taseko Mines' data also showed losses of up to 80% of stream flows to groundwater in some streams upstream of the Tailings Facility, but Taseko later recanted this data, saying that losses were due to data errors.
Stratus' scientists wondered if, given such significant data errors here, are there similar errors elsewhere in the water budget model? Taseko says that data collected prior to 2000 are unreliable, but if this is true then is the majority of the data in the model also invalid and unreliable?
When asked about having potentially unreliable data, Taseko Mines’ Environmental Director, Rodney Bell-Irving, said that there were legitimate issues around the amount of data that contributed to the water model, and that the current level of sensitivity analysis was insufficient. He was, however, convinced that there was enough information for an assessment to be done, and that it was at the permit stage that more detailed data would be gathered and analyzed.
The Model Doesn't Hold Water?
The Tailings Storage Facility serves to hold tailings in a semi-submerged state to minimize the amount of acid generation and subsequent leaching of metals and other toxins from the tailings. Since the TSF is, in essence, a big, man-made pond of six square kilometers, keeping the water inside the TSF is critical in protecting the environment.
The most significant risk of escape from the TSF comes from acid mine drainage escaping to groundwater, hence the study of the permeability of the material at the bottom of the prospective pond. The upper layer of the proposed TSF is blanketed mostly with glacial till, a dense, gravelly material deposited by glaciers during the last ice age. Till varies in its permeability, so Taseko did a number of tests to estimate how permeable the till under the pond is.
Results of these tests showed a wide variety of permeability, but Stratus Consulting was critical of Taseko's choice of only low permeability results in its modeling. As Stratus writes, using a higher permeability "would have meant admitting losses out of the TSF and the need for even more water into the TSF, neither of which looks good to regulators".
Perhaps even more significant is that fact that the till covers a bedrock aquifer, so the impermeability of the TSF is key to preventing escape of acid mine drainage to that aquifer. The bedrock under the till is basalt, and the fact that this bedrock sticks out here and there within the TSF means that fracturing and faulting in the bedrock is also critical to understanding if water can travel outside of the TSF.
The Stratus report states that the bedrock is more permeable than the till above it, and outcrops within the TSF would act as entry points for contaminated waste to enter the groundwater.
The result of all of this in the model is under-prediction of losses of acid mine drainage losses, as well as under-estimation of groundwater contamination and transport.
Bedrock and Groundwater Are Little Understood
The Stratus scientists go on to discuss how poorly understood fracture systems in basalts are, despite decades of study in the United States. Pathways exist in these basalts for water to travel along, but they are chaotic and unpredictable, making modeling assumptions difficult or even impossible. Taseko deliberately ignored these pathways and refused to incorporate them into their water balance model, according to Stratus.
Faults are also an issue in the TSF, as there are at least two sets of faults that could influence the water balance. One of these may be responsible for stream losses observed on one of the studied streams. An engineering firm, BGC Engineering, recommended that these faults be studied further to understand the fate of groundwater in the area.
Stratus agrees that these faults must be studied further, and state that the faults could easily lead to a "larger and faster plume of contaminated groundwater leaving the mine property."
Finally, there is the issue of "deep groundwater", which refers to a deep bedrock aquifer knowna to exist well below the TSF site. Taseko informed the Federal Panel that "advanced de-watering of the deep bedrock aquifer can supply enough make-up water to maintain the TSF during the early years of mine operation", but when pressed admitted they did not know what capacity the aquifer had.
In other words, Taseko Mines claimed to have access to a significant supply of water to maintain the TSF without actually having any reasonable data to back up the claim. The company’s attitude is also significant in this exchange since, as Stratus says, "the fact that they believe data are not necessary for approval of this mine project underscores the insufficiency of their modeling approach."
Tsilhqot’in: Too Many Unknowns
In general, says Loretta Williams of the TNG, Taseko Mines is pushing something onto the Tsilhqot'in people with "way too many unknowns, and no accounting for extreme weather events or climate change."Taseko has recently announced the mine will have a 33 year life, but no one knows what this is based on and if it's just a smoke screen for their current approval process.”
As far as support from the public, Ms. Williams says that the local newspaper, the Williams Lake Tribune, appears to overtly support a group in Williams Lake that is pushing for the mine. According to Ms. Williams, the Tribune provides little balance in its coverage of the mine issue, and refuses to cover the Tsilhqot'in people's view. She went on to say the newspaper refuses TNG's press releases and does not return calls.
Roger William feels that "Taseko Mines is riding the economy issue [e.g., the latest recession and the call for stimulus], selling the job opportunities, but they don't see the environment as an issue." Now, he says, Taseko Mines is "blaming everything on the Tsilhqot'in people. They go public and say that First Nations are holding up the process. They are a two-faced company that can't be trusted, and they do everything in the media to make First Nations people look bad."
In Williams Lake, members of the public routinely criticize Loretta Williams for her opposition to the mine, accusing "Indian people of all being on welfare". Meanwhile, the Williams Lake Tribune allows overtly racist online discussions of its news articles on its website.
Ms. Williams feels that the public are not digging deeply enough into the issue, and are too easily swayed by pro-mine arguments in the press. She finds that when people do take the time to learn more, they are shocked at potential impacts the mine could have.
At this time, Ms. Williams feels they have "exhausted their efforts on this project", and that a big open pit mine "doesn't fit with Tsilhqot'in plans for economic development within our territory". She says that "even the [provincial] government hasn't respected the decisions of its own courts". She referred to a recent purchase of a sawmill within their territory, and a joint venture in a biomass power plant, as some of the keys to the Tsilhqot'in peoples' future.
Regarding the response of the community of Williams Lake to Xeni Gwet'in, Chief Baptiste says that her people are regularly criticized in public in Williams Lake and elsewhere for their opposition to the mine, and she doesn’t expect this to end any time soon. She says an elder said it best In Prince George: "our people have said 'No', but they [Taseko] are like the Coyote, they keep barking and coming back for more!"
