Editor’s note, Sept. 9: Year for second photo featuring horse cart updated.
Editor’s note: The following is a lightly edited excerpt from the August 2012 Donner Summit Heirloom, the Donner Summit Historical Society’s monthly newsletter.
When the Central Pacific Railroad (CPRR) began work on Tunnel 6 [the longest of 15 tunnels built through the Sierra Nevada mountains], workers drilled holes in the granite, poured in black powder, added the fuse, tamped it, packed it, and sealed the hole. Black powder has at least one disadvantage — when it goes off it leaves behind a lot of smoke that needs to dissipate before work on the new rock face can be started. That slows work down.
Nitroglycerine was invented in 1846; Alfred Nobel invented a blasting cap to set it off the following year. The substance would become a great advantage in conquering the granite of Donner Summit. Not only does it have more explosive power than black powder, it leaves behind little smoke and needs smaller drill holes, 1-1/4 inches instead of 2-1/2 inches. It was very efficient because it blows up in all directions at once, shattering rock. This meant work could progress much faster, increasing progress by 54%. Drilling smaller holes enabled workers to manage three holes in the time two took previously. Instead of progressing only 14 inches per day, the crews could advance 22 inches per day using the new explosive. On the bottoms of the tunnels the change in pace was even more dramatic, going from 17 inches to 53 inches a day.
Nitroglycerine also had the advantage of not breaking up the rock into very small pieces, which meant workers could get in to clear out the rubble much more quickly. The rock can be lifted out in “clean, large blocks,” wrote the Sacramento Union (April 19, 1867).
Nitroglycerine cost less in manpower, but it also cost less per excavated yard, $10 versus $14.80. The total savings was estimated to be $10,000 for Tunnel 6. It was only used in tunnels 6, 7, and 8.
According to the newspapers touting the new technology, nitroglycerine was claimed to be very safe. At the same time at least one report stated, “It is very strange that numerous testimonials of the safety of this oil have been given by many mining superintendents, and engineers, and by military engineers in Europe, while in this country we have already had two destructive explosions of the oil in bulk.”
In April 1866, at the corner of California and Montgomery streets in San Francisco, there was a huge explosion, wiping out a Wells Fargo office … The nitroglycerine had been refused by the person to whom it was sent from the East Coast and across the Isthmus of Panama, so it was stored in the Wells Fargo office. There it was seen to be leaking, and eventually it went off.
Almost at the same time, the April 18 ,1866, Daily Alta California reported, “A terrible explosion occurred at Camp Nine on the line of the Central Pacific Railroad near Gold Run, Placer county [sic], yesterday afternoon, while workmen were arranging a blast. Three white men and three Chinamen were killed, several of them being blown to pieces.”
Although the new explosive could accelerate work on the Sierra tunnels, that speed came with a cost. Later, of course, Alfred Nobel would mix nitroglycerine with materials to stabilize it and make it safer, creating dynamite, though it was not ready to be used on the CPRR. (His sense of guilt about his explosives would also bring about the Nobel prizes.)
The first regular use of nitroglycerine in the U.S. might have been on the CPRR above Donner Lake. For safety’s sake, so as not to repeat another San Francisco accident, nitroglycerine was manufactured at a little factory near Donner Lake. There, James Howden produced 100 pounds of the explosive per day under a “shed roof supported by posts … erected over an old kettle, which was used as a nitrator.” There were red flags around the manufactory set out as warnings. The liquid nitroglycerine was carried by “Chinamen” to the headings.
Why They Stopped Using Nitro
We know that nitro was used beginning Feb. 9, 1867. On May 1, 1867, Edwin Crocker noted that Tunnel 6 had but 681 feet to go. Nitro was discontinued in November 1867. Why did the CPRR stop? Money, my friend, money. Alfred Nobel was granted a Swedish patent on Oct. 14, 1863, and an American patent on Oct. 24, 1865. Crocker, an attorney and later Supreme Court justice for California, was aware of those patents and concerned about infringements. On May 3, 1867, in a letter to American industrialist and railway magnate Collis Huntington, he urged that Huntington pay $500 for patent use. Charles Crocker [one of the CPRR founders and Edwin’s brother], however, would have nothing to do with nitro outside of railroad construction. In the end, Charles said, “Bury the stuff,” and nitro use was stopped.
~ G. J. Chris Graves, chairman, committee for the protection of “What is Truth” in Railroad History, Newcastle, California.
