266 RESOURCES OF CALIFORNIA. 
pay-dirt is very convenient, two men can shovel enough to 
keep the machine in operation. The Burke rocker was exten- 
sively used in California eight and ten years ago, but now it is 
® great rarity. 
$197. Tunnel-Mining.—A tunnel, in Californian mining, is 
an adit or drift entering a hill-side, or running out from a shaft. 
Mining-tunnels are usually nearly horizontal—those entering 
hill-sides having a slight ascent, for the double purpose of 
draining the mine, and to facilitate the removal of the pay- 
dirt. In a few hills the tunnels run downward at an angle of 
twenty degrees or more, to avoid veins or ledges of rock, 
which would have to be blasted through if the tunnel were 
cut horizontally ; but this can only be done with safety in hills 
which are drained by older horizontal tunnels. 
The mining-tunnel does not run through a hill, but only into 
it. The length of tunnels varies greatly; the longest are about 
a mile. The usual height is seven feet, the width five feet. 
Ordinarily the top must be supported by timbers, to prevent 
it from falling in, and not unfrequently the sides must also be 
protected by boards. The cost of cutting a tunnel varies from 
two to forty dollars a longitudinal foot, according to the nature 
of the ground, the cost of getting timbers, &c. Tunnels are 
usually made by companies of eight or ten men, of whom one- 
half may be merchants, lawyers, physicians, or office-holders, 
and the remainder laboring miners. The latter class do the 
work; the former furnish provisions and tools, and a certain 
amount of cash weekly until the pay-dirt is reached. Two or 
three men work at a time cutting a tunnel; one or two to dig 
the dirt; and one or two to haul it out. The dirt of the first 
fifty yards is hauled out in a wheelbarrow; beyond that dis- 
tance a little tram-way or railroad is laid down, and the dirt is 
hauled out in cars, pushed by the miners. It is not customary 
to use horses. It is common to have two relays of laborers— 
one set working from noon to midnight, the other from mid- 
night to noon. Work in a tunnel is as pleasant at night as in 
the daytime. When acompany is rich, or has many laborers, it 
