- Mining Terms. 163 
Bar D:iectnas. Gold washing on river-bars. 
Barriers. Posts of unworked gangue or coal left 
to prevent drainage from mine to mine. 
Basr Buution. Pig lead containing its gold and 
silver unseparated. 
Base Merats. All metals except gold, silver, mer- 
cury and the platinum group, which are termed noble 
metals. 
Bep. A horizontal seam or deposit of ore. 
Bep Roox. The solid rock outcropping at surface 
or underlying the gravel, slide or other loose earth. 
Bismutu. A hard, brittle metal of grayish-white 
color, reddish tinge, used chiefly as an alloy. At. wt. 
210; symbol Bi. 
Buack Jack. A dark variety of zinc blende, or 
sphalerite. 
Buienpe. A sulphide of zinc. 
Buiossom. Decomposed outcrop of a vein. Gossan. 
Tron hat. 
Buiow-our. A spreading out-crop. 
Bonanza. Fair weather at sea; a large body of 
paying ore. Became a familiar term upon the opening 
of the immense ore bodies in the Comstock. Sp. 
Boomine. A kind of placer mining where the 
water is accumulated in a dam and let out at intervals, 
so as to utilize its cutting power in the form of a torrent. 
Boom Ditcon. The ditch from the dam used in 
booming. (2) A slight channel cut down a declivity 
into which is let a sudden head of water intended to 
cut to bed-rock and prospect for the apex of any under- 
lying lode. 
Borraska. The reverse of bonanza. Out of pay. 
Boutper. A large, loose, rounded stone. 
Breast. The heading of a drift, tunnel, or other 
horizontal working. 
Brecota. A conglomerate of angular fractions. | 
BritTiLe Sitver. Stephanite. A sulphide of anti- 
mony and silver containing 68.5 per cent silver with the 
antimony variable. Sometimes contains iron, copper 
