Nostalgia & History > What is a double jack?

I did a search on the George Anderson website for Bingham Canyon and got a picture of a Drilling Crew with a letter to Jackson Thode attached.

Picture 1 is from the website,

http://contentdm.lib.byu.edu/cdm/singleitem/collection/GEA/id/11369/rec/1

Picture 1, Portion of picture that was letter to Jackson Thode.

---

Picture 2, Enlarged 100%, “Call Number: MSS P-3289 # 45. Title: Drilling crews. Photographer: Anderson, George Edward, 1860-1928. Contributor: Ozment, James L. Description: A drill and blast crew on a dry spot of land in the middle of a snowy area between two hills or mountains. The long steel rods were drill steel, and two of the men are hand drilling, one with a double jack and the other on his knees holding the drill steel. Those huge cuts were apparently all drilled in this manner. Date: ca. 1880-1920. L. Tom Perry Special Collections, Harold B. Lee Library, Brigham Young University. Place: Bingham Canyon, Utah. Physical Description: gelatin silver print or collodion print; matte finish; 12.07 x 16.51 cm. (4.75 x 6.5 in.).

---

Picture 3, picture 2 Microsoft Picture Office Picture Manager, Brightness -9, Contrast 31, Midtone 70.

---

Tried Google and found a modern description and photos of tools:

http://www.fhwa.dot.gov/environment/recreational_trails/publications/fs_publications/84232602/page01.cfm

"Double jack

These large driving sledges have 36-inch handles and 6- or 8-pound heads. Because their use requires considerable expertise from both the driller and holder, we recommend that you use single jacking or modified double jacking until safety and proficiency with the double jack can be assured."

Three rocks and four fingers worth. Now that's a double Jack! Oh, you were referring to something else. My bad!

KC - Whaaaat? It's Memorial Day!



Edited 1 time(s). Last edit at 05/26/14 15:54 by GRNDMND.

The guy in the light shirt is holding a double jack (depending on the definition) or part of the double jack (along with the other sledge driver in the dark shirt and the driller kneeling down). Usually, it is two men each with a sledge, one with a drill. The poor sap on the drill has to rotate the steel in the whole so that the points are on "new" rock, in order to make a straight hole. That guy has to constantly rotate and keep the drill at the right angle and has to keep his hands clear of the sledge while also rotating and allowing the drill to freely move during the hit. And, he has to be ready to pour some water into the whole to act as a lubricant and a mucking agent - it creates a mud from the dust of the broken rock. It's an accomplished art, and you usually see guys with all sorts of hand injuries.

Basically, when you're double jacking, the second hammer is at the apex of the swing as the first one is coming off the steel. Which gives you an idea of how much tiem is allowed to move the steel, and the accuracy of those two swings.

A single jack is either a single headed sledge (which is loads of fun to use due to the weight disparity) or one man hitting the steel another is holding OR one man hitting the steel HE is holding. NOTHING is as clear to a man as when he has hit his thumb between the hammer and the steel while single jacking. Or having your "buddy" do it for you while double jacking. Good cloves, with thick leather help - but you still have to rotate, keep straight and pour. And, the vibrations from the steel to your hand can be somewhat nerve wracking. Oh - and the thought that a steel sliver, thrown off the steel (or head) by an errant (or even a perfect) hit, and the possible results when said sliver reaches your eyeball is always present.

If you've seen several of the movies with the building of the transcontinental RR, there are usually scenes of two guys with mauls hitting a spike, in the same manner (though a lot less weight and a lot less danger).

Thanks to TCnR and rsweber for the information and to GRNDMND for the Memorial Day levity.

I found websites for both single jack and for double jack.

http://www.miningcontest.com/SINGLE_JACK.html

SINGLE JACK
The driller, referred to as a “cousin jack” wielded a 4lb hammer and drove a chisel pointed steel into the rock. The miner would strike the chisel with the hammer, and rotate the chisel 90 degrees before striking it again. When this process was used in actual mining, miners would spend entire shifts drilling by candle light. It was a dangerous labor-intensive occupation within the tight confines of the mine. Miners would regularly drill overhead or horizontally following the veins of ore. Single-jack drilling quickly became a highly regarded competition. Mines would sponsor their strongest, most skilled men in competing at the events. Payouts were also very large, sometimes offering as much as a year’s wages in prize money for 1st place. Entire communities would turn out to watch the men compete.
“ One of the greatest of the old time drillers was Fred Yockey, who was undefeated in single jack competition. In 1903 in Bisbee, AZ, Yockey drilled 26 5/8” in 15 minutes in a block of Gunnison granite, a record which still stands for a 15 minute contest.” Rock Drill Data
One known single-jack record was set by Fred C. Dopp of Jamestown Co. He was said to have drilled 18.5 inches in a ten-minute competition. He was also said to have won the world championship for 30 years running (The Sunday Camera, Sunday Feb. 13th 1977).

http://www.miningcontest.com/DOUBLE_JACK.html

DOUBLE JACK
Double jack drilling referred to a two-man drilling team. One man holding the steel with his bare hands was known as the “shaker”. His job was to hold the steel in position and then rotate it 90 degrees after every blow from the sledge hammer. The other man known as the “driller” would swing an 8-12 lb. sledge hammer at the rock chisel being held in the shaker’s hands. The driller’s job was to strike a firm blow, and never miss.
“A 24-inch hole was generally considered a good depth in a ten-minute contest.”
During a 15min. contest in Colbalt, Canada in 1909, a pair of double jackers drilled 43 1/8”- this, however, was not granite.” (The Sunday Camera, Sunday Feb. 13th 1977)
George Coughlin and Mick Coughlin were four-time world-champion double-jack drillers (1936-40) from Boulder, Co. George described the several advantages to their winning style:
“We used the slip handle technique. We would pick up the hammer and slip a hand onto the top of the handle, then throw the handle down. Everybody else kept their hands at the bottom of the handle and sort of chopped away. You had to start easy so you would get the hole going straight. Then when we’d get down 6-8 we’d begin fostering.” Fostering meant that the man holding the steel would let go of it while he picked up his hammer to prepare to swing. Meanwhile the man drilling kept at it until his partner was in position to start. At the end of every 30 seconds they would change places. (The Sunday Camera February 20th 1977).