The Greathouse Portal Visitor Center, inside the former Hazel-Atlas sand mine, is open again after five years. Photos by Andrew Alden

With California's state parks under threat of imminent closure, the East Bay Regional Park District is a bright spot for naturegoers. Careful management has maintained steady funding in hard times, and this summer EBRPD's Black Diamond Mines Regional Preserve promises to be a well-attended place—especially with the long-awaited reopening of its underground Greathouse Visitor Center.

Black Diamond is named for its history as California's largest coal district, starting in the 1850s. Coal was a prerequisite of 19th-century technology, and its discovery in the hills south of Antioch helped propel the new state of California to prosperity. It wasn't great coal, being classified as lignite or the lowest grade of coal, but it was good enough to do the job. Several mining towns sprang up here, and for a while this was the biggest settlement in Contra Costa County.

Fragments of Black Diamond's low-grade lignite coal can still be found in the tailings piles.

The coal didn't run out, but by the 1890s better coal was available from elsewhere so the mines shut down soon after. Next came the exploitation of the premium quartz sand beds beneath the coal. The sand mines supplied glassmakers in Oakland and steelmakers in Pittsburg from the 1920s to the late 1940s. That was when the Greathouse underground chamber was created, in the Hazel-Atlas sand mine. The Regional Parks District repurposed it as a visitor center in the 1970s, but storm damage shut it down in 2007. After five years of painstaking rehab, the room is receiving visitors again every weekend at no charge.

The old mining district is hidden from the riverside sprawl of Antioch behind a narrow canyon and oak-dotted hills. Driving through the canyon is like leaving the 21st century behind.

Inside, the vegetation is more lush on the higher hills, and miles of trails snake through the country. The area is notable for wildlife and plant species, but geologists find it notable too.

The bones of the hills are relatively young sedimentary rocks that are well exposed here. They extend all the way across the Central Valley in the subsurface. I look forward to showing you more as I explore this beautiful place.

View west from Almaden Quicksilver County Park toward Loma Prieta, highest peak of the Sierra Azul. All photos by Andrew Alden.

In the foothills due south of San Jose sit the remnants of California's first mining bonanza, the New Almaden mercury district. Today Almaden Quicksilver County Park is a rugged playground for hikers, bicyclists and equestrians, but lovers of geology and mines have a special kind of fun there.

The first Californians mined a deep-red ore they called mohetka in the heights of Los Capitancillos Ridge. Like other ancient peoples around the world, they used it as a pigment. In 1845 a Mexican visitor recognized the substance as cinnabar or mercury ore. Soon afterward the New World's richest quicksilver mining district began production, supplying the mercury for the refiners of the California Gold Rush. Its name, New Almaden, echoed the famous Almadén mines of Spain. A hundred years later, the mines had yielded mercury in the amount of more than a million flasks—a volume of the liquid metal weighing 76 pounds. Although mining ended in the 1970s, geologists believe that much undiscovered ore remains.

Let's look at the geologic map of the area (derived from USGS Map OF-98-975).

The New Almaden district runs northwest on Los Capitancillos Ridge from the village of New Almaden. Asterisks mark the four park entrances. Franciscan rock units are fm, melange; fpv, volcanics; gs, greenstone; pink, serpentinite; yellow, silica-carbonate rock; orange, chert. Units with names starting Q, T or K are younger.

It's kind of a mess, and the details are in the caption, but basically Los Capitancillos Ridge is like many other Bay Area mercury sites, an intricate mixture of Franciscan rocks and serpentinite that has been kneaded and heated and injected with metal-bearing fluids. These fluids, derived from magma intrusions, replaced the minerals in the serpentinite and turned it into silica-carbonate rock. The cinnabar lodes, in turn, were emplaced in and near the silica-carbonates. As you hike about the ridge, keep an eye underfoot for the widespread serpentinite.

Serpentinite boulders in a streambed.

Among other things, the park contains mines and machinery spanning a century of progress from traditional techniques of medieval origin to modern American facilities. One mine entrance, the San Cristobal tunnel, has been kept open for a short distance.

San Cristobal tunnel, first opened in 1866.

Go on in and look for the veins in the walls. These are typically filled with quartz or dolomite.

Veins in the San Cristobal tunnel.

Another worthwhile spot is the site of the Buena Vista shaft, the deepest in the district. The foundation of the pumphouse is constructed of large blocks of local sandstone and Sierran granite. It was abandoned in 1893.

The Buena Vista shaft mainly served to dewater the hills and allow neighboring mines to go deeper in search of cinnabar.

Nearby are extensive piles of mine tailings. Although this shaft produced only minor amounts of ore, the rocks themselves are interesting. Remember that collecting rocks and minerals is forbidden. A ranger told me that if people kept taking things home with them, eventually there would be no tailings left. I don't see the problem with that, and if I could make the rules I would give rockhounds access to limited parts of the park.

Don't miss the views of the surrounding territory. The top photo of this post shows the view west to the Sierra Azul, and to the east are views of the Santa Teresa Hills and Diablo Range.

Mount Hamilton's observatories stand out beyond the lower Santa Teresa Hills, site of more mercury mines and sandstone quarries.

The mining museum housed in the Casa Grande, the old manager's residence built in 1854, is full of exhibits and is well worth a visit if you can be there during its brief open hours.

The Casa Grande has rooms full of period furnishings as well as the Quicksilver Mining Museum.

The little museum shop has cinnabar from the Guadalupe Mine for sale. This is the only way you can acquire New Almaden specimens today, unless a dealer is selling off a historic collection at a rock and mineral show.

New Almaden cinnabar is notable for its tiny crystals that give the ore a glittering appearance.

The definitive source for historic and geologic information on the area is the classic US Geological Survey Professional Paper 360, "Geology and Quicksilver Deposits of the New Almaden District."

Nestled among the trees, streams and undeveloped land in Northern Wisconsin rests an environmental, societal and political challenge. The pristine area, with its proximity to Lake Superior, the largest fresh-water lake in the world, is why its residents choose to live there, but the area is also home to 25 percent of the country’s iron ore reserves, a commercial value of $200 billion.

Pete Rasmussen and Jamey Francis embody the conflict residents in the area face. Both are from the area. Both went away for college. Both moved back to enjoy what the area had to offer. However, the former doesn’t want to risk the change an iron ore mine could bring, the latter feels the mine would staunch the change that’s already occurred.

The four and a half mile stretch of land in question straddles Ashland and Iron Counties in an area colloquially called Wisconsin’s Northwoods. Since 1965, Iron County, an area where a history of mining is celebrated through streets signs and family history, has seen its population decline by 80 percent. Some, like Francis, see the proposed mine and the thousands of jobs it offers either directly or indirectly as a chance to save the county with the one of the highest unemployment rates (8.6% in September) in the state.

“There’s not going to be any opportunity that I can see in the near future other than this mine,” said Francis, an apparel salesman and city councilman in the town of Hurley. “This is an economic game changer.”

The company proposing to develop the mine, Gogebic Taconite (GTAC), has sponsored community events for most of the last year and held open houses throughout the region in an effort to drum up support. GTAC has also lobbied Wisconsin lawmakers to change state law to treat ferrous mining separately from sulfide mining as Michigan and Minnesota do. Iron ore mining uses water and magnets to extract the iron while sulfide mining uses chemicals to remove the deposits.

Among the legislative changes the company wants is a finite time line for the Department of Natural Resources to approve or deny a permit request. GTAC is also interested in being granted the ability to mitigate damages to currently protected wetlands by creating 1 ½ acres of wetland for every acre damaged in the process.

Critics fear the legislation is code for simply ramming through a strip mine without concern to the environment.

“The possibility of poisoning the water for future generations isn’t worth it to me,” said Rasmussen, a freelance photographer, web developer and carpenter in the area. “We’ve known it would be a struggle up here to get by, and it is for a lot of folks and they have to maybe take a couple of jobs. But it’s worth it. It’s part of the price you pay to live in such a beautiful place. And we’re here to protect that.”

The Republican-led legislature is moving forward with legislation to change Wisconsin’s mining laws in order to “get people back to work.” The head of the State Assembly, Rep. Jeff Fitzgerald (R), says there’s “no more important an issue” facing lawmakers in the next few months.

Cinnabar from Lake County. Photo by Andrew Alden.

It's widely known that California has a mercury problem unlike other parts of the world. We don't produce it and we don't emit much any more, but a lot of old mercury is still lying around from the mining days. How did that happen?

In undisturbed nature, mercury is no more than a very local and very temporary problem. Mercury occurs mostly in sulfide compounds that are concentrated where ore-forming fluids invade metal-rich rocks. Cinnabar and metacinnabar are both mercury sulfide, HgS. Metacinnabar forms at higher temperatures.

Metacinnabar from the Mt. Diablo Mine. Photo by Andrew Alden.

The California Coast Range was a natural place for world-class mercury ore bodies to grow. First, the range has a large amount of metal-rich rocks in the form of serpentinite and its parent rock, peridotite, derived from ancient seafloor. Second, these rocks were cracked and tilted as the Coast Range was built. Third, volcanic activity worked over these rocks, adding heat and chemically active fluids. Thus the source rocks were repeatedly mobilized, attacked and disrupted, a natural refining sequence that at each step concentrated metals.

Serpentinite is a slippery rock that tends to attract faults, which in turn attract fluids. Hot deep fluids replaced the serpentinite with carbonate minerals like calcite, then again with silicate minerals like quartz. As veins of these minerals fan outward they carry mercury with them. Coast Range mercury was originally deposited at high temperatures deep underground, often associated with gold sitting a bit deeper. It remains for erosion to slowly uncover the ores. In coastal California, erosion is quite active as the Coast Range continues to rise.

Wide zones of silica-carbonate alteration dot our mountains and host hundreds of mercury occurrences. The great New Almaden Mine, south of San Jose, exploited a deposit of this type. It was the largest mercury producer in North America, spawning the gold mining industry that followed the placer gold rush of 1849. Cheap, efficient mercury amalgamation was the key to gold production, and New Almaden mercury made it feasible.

Yuba Gold Dredge 17, still working the Sierra gravels, uses mercury amalgamation to capture flour gold. Photo by Andrew Alden.

Volcanic heat also spawns hot-spring activity that can create mercury ore bodies, too. The McLaughlin Mine, north of Lake Berryessa, exploited a hot-spring type deposit yielding gold as well as mercury.

Today the mercury mines of the Bay Area are all closed and being remediated. The New Almaden property is now a county park and the McLaughlin Mine is being carefully restored to a working countryside. Fortunately, mercury can be well controlled if acid mine drainage can be prevented, because cinnabar is poorly soluble except in strongly acid waters. At Clear Lake, the large former Sulphur Bank Mine is slowly getting under control. The privately owned Mount Diablo Mine, where my metacinnabar specimen was collected, is not a threat to spill into local streams although money is needed to fix it for good.

Worldwide, the overwhelmingly largest source of mercury pollution is from the burning of coal. A much smaller source is from oil and gas. Mercury appears to ride along with oil and gas as they trickle from their source rocks upward into the reservoirs we mine for energy. In oil, mercury lives in the tiny metal portion; in gas, mercury is a vapor. Levels in both are in the low parts-per-billion range, although California's oil tends to have relatively high levels. Mercury levels are highest in the dense fraction called petroleum coke, which is burned in place of coal. Even so, coal is far dirtier in terms of mercury, and the Bay Area is spared that insult.

More reading:

• Mercury Cycling and Bioaccumulation in Clear Lake, special issue of Ecological Applications
• Mercury Geoenvironmental Models by James Rytuba (US Geological Survey)

Mercury is a poisonous metallic element that is liquid at room temperature.

There's nothing like producing a controversial story on some favorite food group to have a profound effect on one's appetite. I gave up chicken after doing a story on factory farms (I already didn't eat beef or pork or I would have eliminated those as well.) Now, fish, too, has fallen from grace. Ignorance was bliss.

I've known for quite some time that some fish, especially tuna, were high in mercury. But discovering the extent of the problem, and that halibut and sea bass were also on the “do not eat too much of” list, was eye-opening for me. Now I count fish servings like some people count calories. Japanese cuisine, one of my favorites, has lost some of its glow, as well as its frequency in my dining-out plans.

Many of you have practical questions, as did I. How big a crimp does this have to put in my diet? How much is too much? How often is too often? Can I still enjoy that tuna sashimi and not worry about mercury overload?

Because there wasn't time in the QUEST TV segment on mercury in the bay to include information on safe fish eating practices, below are the guidelines, along with web links, to help you get plenty of Omega 3s and still keep your mercury levels low.

Here's what California's Office of Environmental Health Hazard Assessment says about eating fish from the San Francisco Bay and Delta Region.

• Women beyond childbearing age and men should eat no more than two meals per month of San Francisco Bay sport fish, including sturgeon and striped bass caught in the delta. (One meal for an adult is about eight ounces).
• Women beyond childbearing age and men should not eat any striped bass over 35 inches.
• Women of childbearing age, pregnant, nursing mothers, and children should not eat more than one meal of Bay fish per month. In addition, they should not eat any striped bass over 27 inches or any shark.
• This advisory does not apply to salmon, anchovies, herring, and smelt caught in the bay; other sport fish caught in the delta or ocean; or commercial fish.
• Richmond Harbor Channel area: In addition to the above advice, no one should eat any croakers, surfperches, bullheads, gobies or shellfish taken within the Richmond Harbor Channel area because of high levels of chemicals detected there.

Here’s a summary of the joint fish advisory published by the FDA and EPA for women who are pregnant, breastfeeding or may become pregnant and for children. This is a general advisory not exclusive to any water body.

• Do not eat Shark, Swordfish, King Mackerel, or Tilefish because they contain high levels of mercury.
• Eat up to 12 ounces (2 average meals) a week of a variety of fish and shellfish that are lower in mercury. Five of the most commonly eaten fish that are low in mercury are shrimp, canned light tuna, salmon, pollock, and catfish.
• Another commonly eaten fish, albacore ("white") tuna has more mercury than canned light tuna. So, when choosing your two meals of fish and shellfish, eat only up to 6 ounces (one average meal) of albacore tuna per week.
• Check local advisories about the safety of fish caught by family and friends in your local lakes, rivers, and coastal areas. If no advice is available, eat up to 6 ounces (one average meal) per week of fish you catch from local waters, but don't consume any other fish during that week.
• Follow these same recommendations when feeding fish and shellfish to your young child, but serve smaller portions.

Also, check for local advisories for each water body in California that has fish consumption guidelines. They vary by water body.

And lastly, here’s some practical advice from Dr. Jane Hightower, the medical doctor who we feature in the mercury story.

• “If you’re genetically susceptible, it’s really important to know that if you are an autoimmune-prone patient, Lupus, MS, thyroiditis, these kinds of things, then you should not consume mercury on a regular basis or at all. … And then the cardiac patients. You know, mercury can cause a reaction in vessels that leads to inflammation. So you want to have your Omega 3 fatty acids, which is anti-inflammatory. And not have mercury which is pro-inflammatory…. If you want to avoid significant mercury and you just don’t know what the mercury content is in the fish, a rule of thumb is to eat the small fish. Not a piece of the fish. If it comes in a steak, you want to know how big the fish was that the steak came from. You want the whole fish to fit on your plate. Don’t buy a bigger plate. Get a smaller fish. With the exception of salmon. Salmon can have elevated mercury, but very rarely.”

Good luck, good health, and and watch out for bones!




Watch the Mercury in San Francisco Bay television story online.




37.8627 -122.318

Tags: almaden, gold rush, mercury, mining, poison, pollution, total maximum daily load, toxic
]]> http://science.kqed.org/quest/2009/10/06/producers-notes-mercury-in-san-francisco-bay/feed/ 0 37.8627000 -122.318000037.8627000-122.3180000 http://science.kqed.org/quest/2008/04/18/reporters-notes-mercury-in-the-bay-part-1/ http://science.kqed.org/quest/2008/04/18/reporters-notes-mercury-in-the-bay-part-1/#comments Sat, 19 Apr 2008 02:29:06 +0000 Amy Standen http://www.kqed.org/quest/blog/2008/04/18/reporters-notes-mercury-in-the-bay-part-1/

View Larger Map

In honor of Earth Day, we wanted to take a big look at a chronic environmental issue in the Bay Area, tracing it from its origins to the contemporary strategies to solve it. Mercury was the obvious choice: It's been flowing into the Bay since before California joined the union, and it continues to trickle in from not just the old culprits, like gold and mercury mines, but a modern crop of industries, like refineries and cement kilns. Even little things – like a broken mercury thermometer dumped into the sink – are part of the problem.

The key fact here is how incredibly potent mercury can be: Just one little globule from an old thermometer can poison all the fish in a 45-acre lake, making them unsafe for humans to eat. Mercury pollution is hardly unique to the Bay Area; what makes us interesting is that local officials are making real strides in trying to clean it up. Over the next 17 years or so, we'll spend $2.6 billion dollars on the project. Even then, we won’t have a clean bay for 120 years.

For a lot of people, mercury pollution in the Bay is largely theoretical, since few stores sell fish caught in the Bay, and relatively few residents fish for their food. But some still do – including many recent immigrants from fishing-intensive cultures like Laos. We’ll look at how mercury affects the health of local fishermen next week.

This piece marks our first-ever audio slide show, and what a difference it makes! We also hope you'll check out the mercury map above, where you can see how many pounds of mercury come from each of the Bay Area’s five refineries, plus other mercury sources and the bay's popular fishing spots.

Watch the audio slide show of "Mercury in the Bay" online, as well as find additional links and resources.

Amy Standen is a Reporter for QUEST and Radio News at KQED-FM.



37.179 -121.819

Tags: almaden, cinnibar, gold, gold rush, kqed, kqedquest, mercury, mine, mining, pollution, quicksilver, Radio, water, watershed
]]> http://science.kqed.org/quest/2008/04/18/reporters-notes-mercury-in-the-bay-part-1/feed/ 0 37.1790000 -121.819000037.1790000-121.8190000 http://science.kqed.org/quest/video/mercury-in-the-bay-part-1/ http://science.kqed.org/quest/video/mercury-in-the-bay-part-1/#comments Sat, 19 Apr 2008 00:00:00 +0000 Amy Standen http://science.kqed.org/quest/video/mercury-in-the-bay-part-1/ You might not know it from the textbooks, but California's gold rush was also a mercury rush. Quicksilver mines near San Jose provided gold miners with the mercury they needed to separate gold from ore. 150 years later, we're still facing the consequences of gold-rush era mercury, much of which is lodged in the Bay's mud and in its fish.

Historical mercury mining photos courtesy of the New Almaden Mining Museum, with special thanks to Art Boudreault.

Tags: Almaden Mining Museum, mercury, mining, pbs, QUEST, san francisco bay
]]> http://science.kqed.org/quest/video/mercury-in-the-bay-part-1/feed/ 0 37.179 -121.81937.179-121.819