Mohave County’s mining history includes schemes to mine gold, silver, copper and uranium. But guano?

Amid the splendor of the Grand Canyon there once was a miracle of engineering: a "bat cable" that stretched from the south rim of the canyon to an intermediate tower 850, feet below" then 7,500 feet across the canyon to the north rim.

The remains of this marvel of engineering can still be seen at Guano Point, a tourist destination on the Hualapai Reservation.

 It sounded like a good idea. Engineers estimated that a large bat cave in Granite Gorge, about 18 miles northeast of Pierce Ferry Road on the north side of the, Grand Canyon, would yield 100,000 tons of guano - bat excrement

The cave was once occupied by millions of bats that deposited vast amounts of the "black gold," and the plan was to extract the guano, bag it at the mine about 600 feet above the Colorado River and lower it to a tramway for transport to a landing strip.  The guano would be loaded on to helicopters and taken to the Hualapai reservation overlooking Quartermaster Canyon.

From there the high nitrogen bat guano would be loaded onto trucks and taken to Los Angeles, a market for nitrogen rich fertilizer.

Interest in the venture grew during the 1930s when a young man discovered the cave.

Upon learning of the find, two men tried to mine it, but their barges sank in the river and they abandoned their efforts and sold the property to King-Finn Fertilizer Co., which tried several methods of removing the guano.

George Steinke of Kingman flew a small piece of earth-moving equipment into Granite Gorge piece by piece, according to a story in an April 1973 edition of the Mohave Miner.

King-Finn also managed to build a small airstrip on a sandbar below the cave. However, attempts to remove the guano by barge and then by aircraft failed after the river washed out the sandbar and the airstrip disappeared.

King-Finn sold the property U.S. Guano Corp. of Calgary in 1958. The corporation leased the bat cave from Lake Mead National Recreation Area, which permitted mining.

Consultants told corporation officials that the only way to get the guano out of the cave and canyon was with the installation of an extensive cable system. So a $1 million cargo-carrying tramway was built across the canyon.

The main span was 7,500 feet. The tram needed 9,820 feet of continuous one and one half inch cable (built of one-eighth inch steel rods wound together); 20,200 feet of one and one-eighth regular plow steel cable for the pulling cable; and one large bucket big enough to carry six men and 2,500 pounds of bat guano. A crew of 18 men spent a year and two months working 10 hours a day, seven days a week to build the tramway.

No blasting was allowed for fear that the roof of the cave might fall in, so all anchors for the cable towers had to be drilled 27 feet deep regular jackhammers and the rock broken by use of expanding studs.

The guano was sucked from the cave by large vacuum hoses and stored in a holding bin where it could be transferred to the tramcar. Load after load went into the tram and was moved across the canyon to the south rim, where the guano was put into one-, five-, 10- and 25 ­pound sacks. It was then trucked to Kingman airport and taken to markets on the West coast.

After five months of operation a splice in the cable was deteriorating and required a specialist from Switzerland to splice in 60 feet of replacement cable. When the replacement cable began deteriorating, United States Steel was forced to replace it.

Soon after, officials discovered the bitter truth of the mine. The cave did contain bat guano but not as much as first thought. In fact, the cave contained only about 1,000 tons of bat guano. The rest of the deposit was decomposed limestone, which was of no value.

The company had spent $3.5 million to salvage 1,000 tons of guano, which sold for 69 cents a pound - a grand total yield of about $1.4 million before expenses.

A few months later, a low-flying plane from Nellis Air Force Base clipped one of the cable strands, losing six inches of wingtip and severing the operating cable.

The remaining support cable was used one last time in 1959 when Columbia Pictures filmed "Edge of Eternity" starring Cornell Wilde. Scenes from the movie were filmed in Kingman and the climax showed Wilde and another character duking it out in a fight to the death while stranded 4000 feet above the Grand Canyon in the tram car.

Another movie, a promotional film called "The Treasure of Granite Gorge," chronicled the story of the "black gold" that was taken from the depths of the gorge for the purpose of bringing "colorful" beauty to the gardens and homes of America.

In 1974 the abandoned mine became part of Grand Canyon National Park.

The famous Carlsbad Caverns in New Mexico also contained a bat guano mine, according to information from the Mohave Museum of History of Arts.