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bruce lake

Read today the news that the Brucejack Mine have been given an environmental assessment certificate by the British Columbia Ministry of the Environment.   The regulators say construction can begin once they are sure that discharges from water treatment plants will not harm the Unuk River.  Some of the tailings will go back underground; some will go to Brucejack Lake which is apparently “fishless.”  Most of the waste rock will go to the lake.

I read the following in the June 2014 Feasibility Study and Technical Report Update for Pretium Resource Inc. by Tetra Tech.

Approximately 3.5 Mt of waste rock and 8.7 Mt of tailings are anticipated to be deposited in Brucejack Lake over the projected 18-year mine life. Stringent discharge criteria (based on the Metal Mining Effluent Regulations (MMER)) state that the total suspended solids (TSS) concentrations in the outflow at Brucejack Creek must be less than 15 mg/L.

The tailings deposition system has been developed to minimize the concentration of fine suspended solids in the outflow to Brucejack Creek by discharging near the bottom of the lake (at 80 m depth) and under the accumulations of tailings solids.

On the other hand, waste rock with a wide range of particle sizes is to be deposited in the lake by surface dumping from causeways raising the possibility that fine granular material will be introduced to the surface layer of the lake and to the outflow.

Hydrodynamic modelling of Brucejack Lake was carried out by Lorax (2013) to examine the likelihood of the migration of tailings solids into lake surface waters. The results indicated that the potential for elevated TSS levels in surface waters was unlikely if the minimum particle diameter was greater than or equal to 5 µm.

However, it will be necessary to control the TSS concentrations at the outlet of Brucejack Lake to meet the MMER regulations. The current design basis for control of suspended solids includes the following:

  •  install one or more lines of turbidity curtains at the outlet of the lake to contain suspended solids
  • install a flow monitoring weir across Brucejack Creek downstream from the lake outlet to facilitate monitoring.

An allowance for site investigation and design of the outflow monitoring weir has been included in the capital cost estimate. As a contingency to the use of turbidity curtains, an outlet control structure was designed to allow storage and release of lake water in a controlled manner.

Review of the storage capacity versus lake level elevation for the outlet control structure indicates that flow from the lake could be stopped for a period ranging from several days (e.g. during freshet) to several tens of days (e.g. during the summer and early fall) depending upon runoff conditions in the lake catchment area.

If you have an idle weekend, you can spend plenty of time reading additional documents at this link.   For me it is off to the MET opera, the Tales of Hoffman, so I will say no more than this seems good news:  a BC mine advancing with a rational tailings and waste rock disposal system.  Good for them.  I hope they succeed.

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Goldcorp has announced that it will seek to involve more women in mining.  That is admirable.  Here are some of my stories of women in mining.

The bravest woman in mining I met was but twenty-eight.  She was beautiful and bold.  She drove a large truck at a large mine.  I had spent two years testing the idea that if we let the tailings freeze, then placed a geogrid, a geotextile, and a layer of light-weight coke,  we could ride out  over this floating cover.  I did all the calculations possible.  I tested materials in the lab.  I did trial runs.  Eventually the fateful day arrived–let us drive a large truck out and see if the predicted one-meter deformation was correct.

None of the male drivers would volunteer.  Even though the young twenty-year old bragged about high speeds on highways in his convertible.

She demurely said: “If you will come with me, I will try.”

I sat her and her male colleagues down and explained what I believed would happen: the cover would deform and we would see the level of the tailings aligned with the truck windows.  They all blanched.  But we persuaded the health & safety folk to stand by on the shore, ready with equipment to pull us out if I were wrong.  All her colleagues stood by on the shore as well.

Needless to tell the drive was without incident.  All went as calculated and predicted.  She drove with precision and verve.  I was nervous but simulated calm.  I did not like seeing the road sink, the coke bulge, the tailings ooze, the people in anxious, but expectant observation.  She did it, and we returned to shore and general acclaim.  She will always be my hero and heroine.

Another lady truck driver thereafter offered to take me around the mine in her bigger truck.  I did, although I am sure we broke a few rules doing so.  But she drove so gently and was so friendly, who could resist.

At the upcoming conference Mine Water Solutions to be held in Vancouver April 12 and following, Lisa Wade of Goldcorp will give a keynote speech on Goldcorp’s Water Stewardship Strategy.  I will be there—for Lisa is another of my heroes/heroines.  She epitomizes the best of the best.  Enough said–come if only to hear her.  It will be a seminal event.

Those who have read this blog for a long time probably know that my eldest daughter is involved in mining.  Now she works for Geo-logic.  Two weeks hence I will be with her at the Escobal Mine in Guatemala to observe the dry stack—for she did most of the detailed engineering and now is time to peer review its status a year after start-up.

I have written many postings on this blog about women in mining.  No need to repeat what I have previously said.  A summary is this:  I have worked for and consulted to many women in mining.  And still am doing so.  They are without fail great to work for.  There is a tender, gentle toughness that males do not have.  Plus they are far more intelligent than their male counterparts.  It is fun and a challenge to get them the deliverables they need, want, and demand.

Thus I know that Goldcorp is doing the right thing.  We applaud them, even though their recent announcement makes it even more frustrating that I cannot invest in them because of work for them and these blog postings.

Simple: if you are a qualified woman seeking to work in mining, seek out Goldcorp.  You will do well, I am sure.  Let me know how it goes.

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As a US taxpayer I am at loss to understand how $1 million dollars can be sent to Peru to deal with illegal mining.  Here is a link to one report on the US taxpayer-funded largesse.  The report notes:

The U.S. Department of State awarded US$1 million to the Blacksmith Institute to work with Peru’s Ministry of Environment (Minam) to reduce the use of mercury and design remediation plans in Madre de Dios and Puno, it was announced today.

The United States believes it is crucial to support the Peruvian government strategy to combat illegal mining and reduce mercury use in artisanal and small-scale gold mining.

Where is the Tea Party when we need them?   Have they nothing to say about this blatant waste of money to support a lousy government unable to manage it own affairs?  The only explanation I can come up with is that somebody related to somebody or indebted to somebody has managed to arrange this and is being paid a considerable percentage of the funds.  Smells rank & corrupt to me. Continue Reading »

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A rare victory for the mining industry:  the Chilean Environmental Court has ruled that the Pascua Lama mining project has not affected the glaciers in the vicinity of the mine. Continue Reading »

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A typical Vancouver Saturday:  cool, overcast, some sunny periods, and much reading.   Then after six pm a bottle of wine and an opera. Here are some of the books I dipped into today–I have been reading some for a while; some are old and should have been finished a long time ago; and some are new.  For I am a dipper, i,e., someone who picks up a book, reads part, and then picks up another to read part, as the fancy & interest turn. Continue Reading »

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Another sad story of underfunded mine closure.  According to this report, Yukon Zinc owes the territorial government $3 million in environmental security.  Now the company is bankrupt and also owing $646 million to hundreds of creditors. The tailings management system is described in a report at this link.  The system is described thus: Continue Reading »

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Only one things gives me great pleasure and intense enjoyment: riding my bicycle. This morning it was drizzling as I opened the front door.  Undeterred, I mounted my bike and headed out into the soft waters making the sky & sound. Click to the upper gears and speed down the road past new, cramped townhouses.  Over asphalt and cut logs, cut to make way for a new bridge.  Bounce over the gravel alongside the river and salmon spawning habitat, to the main road clogged with trucks and cars. Continue Reading »

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