The Hostetter Graphite Mine in the Verdugos

I’ve written several times in the past about the legendary “mystery mine” of the Verdugo Mountains. Many remnants of this old mine exist, scattered over the mountainside just south of the 210 Freeway, across from the Verdugo Hills Golf Course, giving us vague clues to an interesting past. Yet no one seemed to know what the mine was for or what its history was. Thanks to some sleuthing, we now know its full story.

The San Gabriels above us were heavily mined for gold and other minerals. There was even a Big Tujunga Mining District in the late 1800s. In the Verdugo Mountains there was mining as well. There was a silica mine and three graphite deposits. One of these graphite deposits was developed into a very successful mine with a mill and processing plant.

The graphite was first discovered here in 1886. Specimens brought back to LA showed good amounts of “plumbago,” the old term for graphite. Graphite had a wide range of industrial uses from steel production to lubricants and, of course, pencil lead. Our graphite was suitable for paint and foundry facings.

The mine was soon opened in a little canyon of the Verdugos and ore was brought down and freighted to LA. The land the mine sat on began to be bought and sold in a speculative fashion, reportedly at one point fetching $100,000. The boosters of Crescenta Valley were abuzz with hopes that development of the mine would result in a railroad into the valley.

By 1899, the mine was in full swing. A large tunnel was producing graphite mixed with granite. Wooden tracks brought ore carts to a crude processing site where a gas engine operated a crusher, mixer and dryer to separate the graphite from the granite. It was yielding several grades of graphite valued from $10 per ton to $125 per ton for the highest grade. A water tunnel above the mine supplied water for the operation.

In 1918, the land was owned by the Hostetter family, who apparently lived near the site on the Hostetter Ranch in Los Angeles. (The fire road coming off La Tuna Canyon Road is named the Hostetter Road.) The mine was leased to a corporation, the Standard Graphite Company, which issued stock to finance a larger mill for processing the graphite. Initially a huge mill was to be built in Montrose that would employ 75 men.

Instead the big mill was built on the hillside about a mile below the mine. Ore carts on steel rails carried the ore down from the mine to a cliff above the mill. The ore was then loaded into carts that were winched down on nearly vertical tracks to a stamp mill and crusher just above the mill. The mill was the latest in technology, a floatation mill. The crushed ore was fed through a series of water-filled tanks. The water was agitated and fed with compressed air, which caused the lighter graphite flakes to separate from the granite. The graphite floated to the top in a froth that was skimmed off. The graphite-filled froth was dried, filtered, processed further and fed into barrels for shipment.

But in the 1920s, graphite began to be shipped in from Madagascar and other countries where it could be produced much cheaper. Unable to compete, the mine and mill closed around 1930. It briefly reopened during WWII when the war interrupted international shipping. The mine was caved in, the tracks removed and the processing equipment scrapped, leaving the empty shell of the mill.

At the mine site today there are several pieces of ore cart track lying around, along with a lot of water and compressed air piping. Flat spots and cement ties indicate where the ore carts rolled to the cliff above the mill, where the winch is half-buried in the hillside. The mill still stands, a massive concrete structure, now completely hidden by decades of overgrowth. It’s only 400 yards from the 210 Freeway, yet is invisible until one bumps into it while bushwhacking.

It’s just another piece of our valley’s history, waiting to be rediscovered.