Science in Sacramento: Researchers and gold miners

This post begins a series called “Science in Sacramento”, which will examine how science effects state policy and vice-versa.

Governor Jerry Brown’s recent line-item veto might have big consequences for… gold miners. Yes, gold miners. Though many California residents likely think of gold mining as an industry of the past, gold mines and other gold extraction endeavors continue to operate throughout California.

Modern miners rarely use gold pans or shovels, but rather a technique called suction dredging. After gravel from a river bed is loosened and pulled through a hose, the heavy gold is separated from the unwanted material by centrifugation. While it is efficient in collecting gold from riverbeds, this process has been shown to disrupt certain aquatic environments.

Peter Moyle, a professor at UC Davis, has studied the Klamath River and demonstrated that suction dredging irreversibly alters the life-cycle of Chinook salmon that spawn there. Moyle’s scientific research interests require him to observe fish in their native habitat; he initially realized suction dredging is a problem because he couldn’t see fish in rivers due to the sediment clouding the water. As a result of this and other research, a moratorium was placed on suction dredging for gold mining in California in 2009 until a comprehensive study could be conducted by the Department of Fish and Gaming.

In an effort to extend this moratorium indefinitely, Assemblyman Jared Huffman (D-San Rafael) included language in the recent budget bill that ensured there would not be enough funding to complete the study. Governor Jerry Brown chose to veto this line of the budget, so the Department of Fish and Gaming will proceed with their analysis. If they find suction dredging minimally invasive to California’s rivers and streams in their report (to be issued this coming November), permits for suction dredging will be issued once more.

Increased gold extraction could mean increased revenues for the state of California, though the amount of possible revenue is widely contested. In these tough fiscal times, apparently the possibility of revenue was enough pressure for Democratic Governor Brown to break from his party and support lifting the suction dredging moratorium. Since all independently conducted research thus far has concluded that suction dredging damages the environment, here’s hoping that the Department of Fish and Gaming doesn’t also succumb to such pressure.

Leave a Reply


  1. Eric Maksymyk


    As a suction dredger I would like to show you the actual science and data that you refer to in your article. A scientist would not show bias but would actually examine the data and the conclusions. The government scientists who did the two dredging studies skewed and cherry picked the data to achieve their results. I did the mercury analysis for the miners for the draft SEIR. It’s easy enough to show you and to prove.

    The facts, as they are stubborn things, are entirely different than what you refer to. It’s too easy to drift into a level of comfort with what “environmentalists” want you to believe. If you would like to actually examine the data I will be happy to provide you with my 40 page data analysis of mercury. The government scientists conveniently ignored findings in the miners favor; used flawed experiment design that did not represent how a dredge operates; ignored the fact that their own findings showed suction dredges remove 98% of mercury in the river and completely ignored over twenty studies of turbidity that showed there were no circumstances where a dredge could harm fish. In fact there is not one documented case of a suction dredge harming any fish in any of the reviews and this after 30 years of suction dredging.

    Want more proof? The government scientist who did the mercury analysis is also a donor to the environmental group that pushed the anti-dredging agenda. This 501(c)3 groups appears to be engaged in lobbying.

    In fact every study to date shows no harm from suction dredging. I challenge you to find a study that does show harm. This isn’t science, it’s opinion. Another example: The leading researcher in the demise of the Yellow Legged Frog, Dr. Roland Knapp, has concluded multiple times that the frogs near extinction is due to the CDFG fish stocking program. There is not a shred of evidence that dredges have harmed frogs, yet the new regulations close half the rivers in the state to “save the frog.” Did you also know that the CDFG is exempt from an EIR for their fish stocking program.

    The truth is different than the simple article you published, for one it is a far more complex story, it’s not one sided. Suction dredges are the only equipment on the rivers that actually remove mercury from the watershed before it migrates to areas where it could methylate.

    If you are truly interested in the science, and by that I mean an objective look at the data without pre-determined outcomes, then I would be glad to provide you with that assistance. As the holder of two Masters of Science I have done my share of research. Sometimes the conclusions aren’t what you thought they should be, but the facts remain, you shouldn’t twist the statistics to support a flawed case.

  2. Rick Solinsky

    Eric, don’t be too hard on her, she is a grad student and I’ll bet you money, her adviser is Peter Moyle. She is just doing what she needs to do to get her degree.

    Also, my guess is that all class-work in Environmental Science is slanted towards the agenda’s of the researchers like P. Moyle. She can’t help it if she isn’t given both sides of the argument.

    If she is really a truth-seeker and doesn’t mind crunching her own numbers (and will dare to contest her adviser’s findings), and really wants to read the truth, she will review your treatise to see how badly the data has been altered to demonstrate the pre-determined results.

    It is really alarming that apparently once a study is published, no one really goes back to re-calculate the numbers to check the findings. In the case of the report you referenced, it is readily apparent that either the grad student that crunched the numbers failed in basic algebra, or there is an alternate agenda and this book was cooked.

  3. I apparently waded into some fairly controversial waters with this blog post, pun intended! Just some clarifications about my personal connections: I neither work for Prof Moyle, nor do I study Environmental Science. My PhD research at UC Berkeley involves studying the plasmonic coupling of anisotropic gold nanoparticles.

    As such, I’ll certainly admit that I am far from an expert on this topic. I’m glad the commenters have been able to supplement the information I provided for the readers. Though I editorialized a bit in my blog post, my main intent was to highlight some of the political maneuvering surrounding this issue. I’ll reiterate that I hope the final decision on this matter can be made from as neutral a political standpoint as possible. Certainly, dogmatic environmentalism can be just as harmful as making decisions for our planet based on budgets and bottom-lines. Admittedly, avoiding these prejudices is a difficult endeavor for a government scientist or analyst; I think we can agree that it is a worthwhile endeavor nonetheless.

    JM Smith

  4. jhm

    Here is your “Science in Sacramento” in action.

    Another mining supply store in CA (Pioneer Mining in Auburn) will be closing it’s doors at the end of this month due to the dredge ban. This company was in business for over 30 years! More jobs lost and more money flowing out of state to online businesses rather than keeping it local.

    Thanks to the biased Indian tribes and their paid off pseudo-environmentalist political backers. Show some backbone people – our rights are being quickly hijacked by a very small minority.

  5. Brian Lambson

    All these comments from the dredging community have sparked my curiosity! A couple questions: how large is CA’s dredging industry nowadays (before the ban)? How much gold is actually being produced each year in comparison with, say, the 1850s? Is dredging a career, hobby, or something in between? Is CA the only state in which it is possible to dredge?

  6. robin trumbull

    hi..i graduated from uc davis, under dr goldman, 1968, and then there were no problems withsuction dredging, it was done all over the state…if you want to protect the salmon, go ahead and protect the rivers below dams, but let us dredgers dredge the seasonal creeks, and rivrs above the reservoirs, where there are no salmon..maybe even restrict dredging to small mom and pop dredges 4 inches and less like they do in oregon and washington which also pretect the salmon…..small dredges are harmless, they mostly move less that a yard of material a day,just small stuff less than 3 inches in diameter…yes, it is true that mercury is removed, usually attached to the gold flakes…economically, the gold miner spends a lot more money going to hotels, restaurants, buying equipment, etc,probably spend $200 a day in total expenses, in the depressed mountain communities, this wouod be very helpful to sustain the economy…I have saved a small fortune in expenses since the ban, stayed at home, worked more, but would really liked to be out there on a mountain stream enjoying the wilderness….by the way, the best way to protect the salmon and trout is to have a moratorium on fishing…!!!!

  7. Nels Sanburg

    After reading the article by Mr. Moyle I can’t believe that this is passed off as science. Perhaps sport and commercial fishing and the Karuk’s insistence on exercising their ‘traditional’ subsistence style fishing is too anecdotal to be considered the real cause of the salmonids’ decline. While the Feds have put severe restrictions on the commercial take, sport fishing that is even catch and release will continue to kill fish. The Karuk’s rights are all about killing fish. The deep holes that Moyle says are so important to salmonid survival are often created by dredgers excavating through the cobble of historic hydraulic debris. The dredging ban is primarily a feelgood salve for the inexperienced and uninformed. One only has to read Moyle’s article to come to that conclusion or go dredge.

  8. Anonymous

    Moyle’s conclusions are deeply flawed. There simply is insufficient data to support his assertion that small-scale suction dredging is significantly deleterious to fish, or their habitats, beyond what other pressures upon the system also contribute. Additionally, there is no reliable data that demonstrates the bioaccumulation of methyl-mercury that can be attributed to small-scale suction dredging…none, yet this premise is being used by state agencies to justify the taking of private property rights from individuals, and to pass onerous regulations, based upon faulty and non-existent science, or the extrapolation from very small sample sizes.

    If it’s the pollution of water sources that is the concern, one need only look at urban waste to conclude that the source of almost all pollution emanates from population centers, not from small rural communities or small-scale suction dredging activities. Care to measure the amount of oil washed from the streets of Sacramento that makes it’s way into the water supply, and then compare it to the amount of oil added to that same water supply by small-scale mining activities upstream? I didn’t think so.

    Care to explore the topic of onerous government regulations from a legal perspective? Read on…