Crosscuts & Drifts

 In Bisbee, crosscut and drifts are the terms used for all horizontal mine workings which, are commonly thought of as “tunnels” by the general public. The terms drift and crosscut have been corrupted by Bisbee miners. The actual definition of crosscut is horizontal workings that cross perpendicular to the trend of the ore or mine workings. Crosscut is typically abbreviated as XC when writing.  On maps, diagrams etc, they will also have number designations  like 86 XC. Drifts are horizontal workings that parallel the trend of the ore or mine workings. Tunnel is only used by persons unfamiliar with mine workings. Actual tunnels are rare in Bisbee mines.   Drifts and crosscuts are normally driven to explore for ore, the drainage of mine workings, ventilation, haulage and access. These mine workings will vary in size.  The smaller sized mine workings were early workings or driven for exploration. In older workings the broken rock was moved by wheelbarrows( Irish Buggy) and hand trammed mine cars. This allowed for a smaller  mine opening to be blasted out. The introduction of mules and motorized haulage required tunnel size to be increased to accommodate the equipment .  Drifts and Crosscuts were typically driven with a upward grade of ¾’ rise to every 12” run. This was in case they encountered water. The gentle grade would allow  the water  to flow  away from the face to a collection point to be pumped. The grade also allows trains to pull loaded mine cars downhill and empty cars uphill.   Western Hardrock mines including Bisbee gave drift and crosscut parts special names. The floor is called the track. The track will have a water ditch cut on one side for drainage. This ditch is better known as a piss ditch.  Walls are called the ribs because a vertical ridge created on the walls each time a round is taken forward. Measuring the distance between the ribs  can tell you how much the working was advanced from each blast.  The ceiling is called the Back. In coal mines it is referred to as the roof or ceiling.  A dead ending of a working in solid rock is known as the face. An opening into other workings is called the mouth and an opening to the surface is called a portal.

  In Bisbee there are 2200 miles of workings, this distance includes raises, shafts and stopes. This makes Bisbee one of the world’s largest underground mines.  All the major mines interconnect, even when they were operated by different companies. This was done to create better ventilation, escapeways and drainage. At one time it would have been easy to have walked from the Queen mine to the Campbell, Dallas, Cole and Junction mines and visited  a half dozen other mines along the way.

The Bisbee underground mines reached this extreme size because of several reasons . The early exploration of ore was done with the driving of drifts, raises and sinking of shafts  vastly increased the mines size. Modernization of the mining techniques caused the earlier workings to become to physically small.  Larger mine cars, animal and motorized haulage and increased hoist capabilities were introduced. Some of the earlier workings were enlarged , others were driven anew to meet these needs. Additional shafts had to be sunk and workings created to service the shafts as the mines followed the  ore trend towards the southeast.     

   104 crosscut Junction mine

Diagram showing how ribs are formed

Main drift Queen Tunnel showing ribs on left side

Reference

Code of Safe Practice for Drift Mining  1955, Phelps Dodge Corporation pp.1 -67

Richard Graeme IV 2010, pers. comm., 8 February

Richard Graeme III  2010, pers. comm., 2 February

graemite@hotmail.com.

© 2013 by Doug Graeme