SINGLE JACK

 

                                                     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).  





        



 

“Champion drillers were kings, known and feted throughout the mining world. The prize money was accompanied by cases of champagne and other liquors.”   Lady in Boom Town, 1904-1922

HAND DRILLING

Hand drilling is a historic method used to drill holes into rock. The purpose of drilling the holes was to fill them with black powder.  When detonated, the black powder would fracture the rock into smaller pieces. This crumbled rock is referred to as muck.  The muck would then be removed with shovels into mine cars and removed from the working face of the mine. Hopefully the muck contained ore, if so that ore would be extracted from the rock during the milling process.

MODERN SINGLE JACK COMPETITION

Single Jack/Double Jack Contests suffered a die out during World War II.  After the war, during the early fifties, a resurgence in mining competitions occurred. The contests are much akin to those held in the 19th century.  The only difference lies in the method of rock chisel (drill steel) fabrication.  At one time all single/double jack chisels  were forged by blacksmiths.  Today’s versions are fabricated with the use of a metal lathe.  The loss of skilled smiths coupled with the desire for tighter gauge tolerances between chisels made turning steels the choice preferred by modern competitors.  Steels are made from heat-treated plain carbon steel.  Carbon steel is same steel that was used during the old times. Rules do not allow the use of alloy steels, case hardened, or tungsten carbon inserts. This is done in an effort to remain as close to the old methods as possible.  Heat treatment tempering and hardening methods remain relatively unchanged.


Colorado contests are five minutes in length.  Nevada contests are a longer ten minutes in length.  Contestants use a hammer weighing no more than 4.5lbs including the handle (“shafted”),  and up to ten steels that each increase 1” in length. The longest steel may not be under 3/4” or .750” in diameter.  Steels are commonly “graduated” as they increase in length.  I.e. the shortest steel is the largest in diameter, and subsequent steels are smaller in diameter.  The purpose of this graduation is to allow the next steel to fit in the hole and not get stuck, or “hang”.  Contestants also use multiple steels to prevent the chisel edge from dulling excessively.  Using the right length steel at the right time allows the driller to steady his hand on the rock to prevent the chisel from wobbling and to reduce risk of hitting his steel-holding hand. 

The rock is generally fine grained granite.  Some of the standard granites used in contests include:  Silver Plume, Eldora Blue, Gunnison Blue, and Sierra White.

Sitting next to the contestant is a person holing their water. The water is sprayed from a small hose (usually copper tipped) into the hole being drilled.  As the water falls to the bottom of the hole it picks up the chisel cuttings and water and cuttings are  hydraulically shot from the hole as the steel is impacted by the hammer.

Rates of striking can vary anywhere from 65-90 strokes per min.  There are two notable styles of drilling. The slower but harder hitting “Colorado” style.  And the faster, lighter “Nevada” style.  Much debate goes into which style is better.  But the fact of the matter is, the best style is the one that wins.


The Single Jack World Championship is held in Carson City NV  During their annual Nevada Day’s celebration.


The current world record was set in 1993 by Scott Havens of Elko Nv.   In  a 10min contest he drilled 16.34” in Carson City NV.

Fred C. Dopp at the Mining Institute drilling contest. Sept. 29th 1936. Civic Center. Denver CO. Courtesy Denver Public Library