Hazel-Atlas Mine Tour

My husband and I signed up for the new extended Hazel-Atlas mine tour at Black Diamond Mines, and met our tour group at the Greathouse Portal. It was 90 degrees outside, but we felt refreshing cool air coming through the portal from deep inside the hill.

The Greathouse Portal - original entrance to the sand mine

The Greathouse Visitor Center

Warren of mine shafts

After an introduction, we hiked about 15 minutes to the Hazel Atlas Portal, and the gated entrance to the Eureka Coal Mine. We learned about coal (the pressurized remains of peat from a vast inland sea), and the coal mining that took place from 1860 -1906 (miners came from all over the world, conditions were hard, and the hours long). Mining was finally stopped because the Mount Diablo Coalfield produced the lowest grade of coal, lignite.

The Eureka Slope - entrance to the Eureka Coal Mine

Eureka Coal Mine

We suited up with our hard hats and LED flashlights and hit the mines. We saw the office, where all workers and visitors checked in for safety. Everyone had to be accounted for in case of an accident in the mine.

Suited up and ready to tour

The office

Veins of coal running through sandstone

Sand mining took place from 1920s -1940s. The sandstone produced silica that was almost 95% pure. It was used by the Hazel-Atlas Glass Company to manufacture bottles and jars in Oakland. The sand is very fine, so easy to see why it was selected for making glass.

Vein of coal running through the sandstone

A chute for loading ore cars with sand

A giant stope left from mining sand

On the tour we saw cutaways of the veins of coal running through the sandstone. We also saw an earthquake fault which was interesting (and sobering). We were grateful for all the rock bolts and special steel-frames protecting the passages. Our tour guide pointed out stopes and chutes, and a mine car filled with sand.

Back at the Visitor Center we learned more about glass production.

Ore car filled with sand	Form for an Atlas-Mason jar
Formed shot glass and jar	Collection of glass products

We finished the tour at the small gift shop, perfect for "Black Diamond" coal specimens, pencils, and black licorice "coal". We finished the day with dinner and conversation  at Casa Orinda Restaurant, an original roadhouse known for fried chicken and biscuits and many other delicious menu items.

This is a wonderful tour for anyone interested in geology, mining, or history. You can order tickets online, or buy them at the Greathouse Visitor Center (tours are small, so can sell out quickly).

Black Diamond Mines Regional Preserve

The hills around Black Diamond Mine Regional Preserve are hollow, with a warren of mine shafts running through them. I've been reading about its coal and sand mines for the last year, and wanted to see it for myself. My husband and I made a late summer excursion from the East Bay out to Antioch to visit this East Bay regional park.

Back Diamond Mine Regional Preserve

Monument to the Mount Diablo Coalfield near Antioch

Black Diamond Mines Regional Preserve is the site of the former Somersville mining town, which supplied glass-making sand to the Hazel-Atlas Glass Company in Oakland, as well as the townsites of nearby Nortonville, Stewartville, Judsonville, and West Hartley. From the mid-1800s to mid-1900s, this was a bustling mining area, which extracted nearly 4 million tons of coal and 1.8 million tons of sand.

View of the Somersville townsite, and the Rose Hill Cemetery on the hill

There is no trace of the former townsite, but the historic Rose Hill Cemetery remains high on the hill (you can spot it via the row of yews that seem out of place in the landscape). I confess we chose to sit in the shade, rather than trek up the hill in 90 degree heat, but maybe next time. As is characteristic of old California mining towns, the buildings were dismantled when a mine is closed, and the wood moved to the next mining site.

Ample picnic area

Shady picnic site

We allowed plenty of time for a picnic under the deep shade of the native oak trees. Mixed in with the native trees, we could see some of the exotic trees that had been planted by the miners, such as black locust, pepper, almond,  eucalyptus, and trees of heaven. The Black Diamond Mines brochure also notes that the park is the northernmost location for Coulter pine, black sage, desert olive, and dudleya. Quite a mix!

Some of these trees may have been planted by miners

View to "the Delta" in the distance

You'll find plenty of trails in the area for hiking and exploring. From one of the trails we could see a view through Markley Canyon clear to the Delta in the distance. I've been hearing about "the Delta" for years, and was glad to finally see a glimpse of it!

Mine tailings

I recommend the Black Diamond Mines Regional Preserve for anyone who loves the California landscape, with a dose of early California history thrown in. The hills are a great place to see wildlife and birds, and reportedly springtime flower displays. I also recommend taking a tour of the Hazel-Atlas Mine.

Point Pinole on a Blustery Summer Day

Point Pinole juts out into San Pablo Bay, with fantastic views of the bay and brisk marine breezes. My husband, aunt, and I made an excursion to Point Pinole Regional Shoreline, near Richmond here in the San Francisco Bay Area, to experience Point Pinole on a chilly summer weekend.

View of the shoreline at Point Pinole toward Crockett

Point Pinole Regional Shoreline

We parked at the Atlas Road Staging Area, close to the Park office. Our goal was to follow the Owl Alley Trail out to the tip of Point Pinole, and then to the end of the fishing pier.

Bench with a view of San Pablo Bay

Shipping lane through San Pablo Bay

Over the years, Point Pinole has had various uses including Native American fishing grounds, cattle ranches and farms, fishing village, and dynamite manufacturing plant. In 1963 the East Bay Regional Park District acquired the land from Bethlehem Steel, and in 1973 the park was opened to the public.

Wetlands pond, still green

The old pier

Point Pinole includes multiple picnic areas, a campground and playground, marshlands, woods, beaches, and a network of trails.  The terrain is fairly flat, which makes it an ideal destination for bicycles, kids, and families. The park provides daily shuttle service from the parking areas to the fishing pier and campsite (check the website for the schedule). The beach trail is included in the ambitious 500-mile San Francisco Bay Trail project, which circumnavigates the San Francisco Bay.

The new fishing pier

View toward Point San Pablo and beyond

The weather was cool and blustery the day we visited, and we were grateful for our windbreakers (this may be the place to be when our Bay Area temperature soars). Afterward we headed for Barney's Gourmet Hamburgers in Albany to warm up over delicious burgers, shared milkshakes, and great conversation.

Intrepid, though chilly, hikers

Roberts Regional Recreation Area

This month we are visiting the last park on our itinerary of East Bay Watershed parks that contribute to our emergency water supply, and provide great recreational opportunities right in our back yard! This time we are visiting Roberts Recreational Regional Park, which is surrounded on three sides by Redwood Regional park. But I'd like to highlight it, because it provides a place to host gatherings as well as enjoy nature.

Roberts Regional Recreational Area

Redwood Grove

Blossom Rock Navigation Trees Exhibit

Manzanita Loop Trail

The 82-acre park opened in 1952, and its entrance is in a second-generation grove of redwood trees. The original trees were logged in 1860, and the current trees are descendants of the famous trees used by ship captains to navigate San Francisco Bay. The original trees were reported to be up to 20 feet in diameter.

View of Mount Diablo from the Vista Point

Sports field with a view of the San Francisco Bay

Swimming pool

Sycamore picnic area

Park amenities include a playground (wheel chair accessible area for children), archery range, sports fields, volleyball court, swimming pool, and picnic sites. Check the Park Calendar on the website for groups hikes, swimming and archery lessons, and hours of operation. Some amenities require advanced online registration, others are on a first-come, first-served basis, so plan your group gatherings accordingly.

Ring of Redwood trees	Redwood needles
Redwood duff	Fall colors

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A network of trails connects with trails through the Redwood Regional Park, providing opportunities for hiking, biking, jogging, and horseback riding. Check out the Graham Trail, Manzanita Loop, Roberts Ridge Trail, and Vista trails. This park may not fit everyone's needs, but it is a place to consider when planning a large group event, or special birthday celebration.

Address:  Recreational Area – 10570 Skyline Boulevard; Oakland, CA 94611  Web Site: https://www.ebparks.org/parks/roberts Map: https://www.ebparks.org/parks/roberts#maps Wild Plants: https://www.ebparks.org/parks/roberts#resources For other parks and preserves in the East Bay watershed, see:  https://edenbythebay.blogspot.com/2017/02/parks-of-east-bay-watershed.html

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Sibley Volcanic Regional Preserve

This year we're visiting several parks in the East Bay watershed that are an integral part of our emergency water supply. These parks and preserves capture, filter, and store water, but they also provide recreational opportunities right in our own backyard! This time we are visiting Sibley Volcanic Regional Preserve, which is the site of ancient volcanic activity from 9 - 10 million years ago.

Sibley staging area off Skyline Boulevard

Self-serve Visitor Center

The Sibley visitor center provides exhibits that describe the geology of "Round Top" (elevation 1763 feet), and a self-guided tour brochure that also describes the geological features. Round Top Road goes from the visitor center to the top of Round Top. Volcanic Trail contains most of the stops on the self-guided volcanic tour.

Sibley's geology

Sibley's geological history

The 928 square acre park was opened in 1936 as Round Top, with the formation of the Park District. In 1972 the park was renamed to Sibley Volcanic to honor Robert W. Sibley, a Park District founder and director.

Overlook Trail

View from the water tower - Mount Tamalpais (upper left corner)

View of Wildcat Fault

Sibley Volcanic Regional Preserve provides great opportunities to study the core of an ancient volcano. Follow the self-guided tour of Round Top to learn more about the site. The picnic site looks a little stark, but I was surprised to find a cooling breeze on the day I visited.

Geo Marker 1: Basalt dike

Geo Marker 3: Orinda Formation gravels

Geo Marker 7: Basalt flow

Picnic Area in a quarry pit

Geo Marker 9: hard and soft lava flow

View to Orinda and Mount Diablo

Round Top Loop Trail circles the peak, and provides stunning views of the East Bay and surrounding hills, from Mount Tamalpais all the way to Mount Diablo. In addition to the view, interesting geology, and excellent birding opportunities, check out the several labyrinths and bring your dog.

Coyote bush - green in mid summer	Teasal
Yarrow	Aster

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The trail is completely exposed, so carry plenty of water, and wear a hat and sun screen, especially in summer and fall. In winter, take the road down to the quarry, and look for the California newts in the ponds near the old labyrinth.

Address:  Sibley Staging Area – 6701 Skyline Boulevard; Oakland, CA 94611  Web Site: https://www.ebparks.org/parks/sibley-volcanic  Map: https://www.ebparks.org/parks/sibley-volcanic#maps Wild Plants: https://www.ebparks.org/parks/sibley-volcanic#resources For other parks and preserves in the East Bay watershed, see:  https://edenbythebay.blogspot.com/2017/02/parks-of-east-bay-watershed.html

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