MATANUSKA AND TALKEETNA BASINS. 121 
Itch 5,700 feet in length, 6 feet wide at the top and 4 feet at the 
Dttom, and 4 feet deep. To the ditch is added a pipe line 3,000 feet 
ng, reduced from 24 inches in diameter at the ditch intake to 15 
iches at the giant. An abundance of water was obtained until Sep- 
smber 8, when the supply fell below 2,000 miner's inches, a quantity 
sufficient to work to the best advantage a plant of this size. Opera- 
ons may begin as early as May 15. Two No. 7 giants, with 15- 
.ch intakes, were installed. The pressure varied between 280 and 
JO feet, depending on the position in the pit- 
Up to September 21 200,000 yards had been moved. The gold- 
iving apparatus consisted of a string of sluice boxes 200 feet in length 
'.cupying a bed-rock cut at a grade of 8 inches in 12 feet. Ample 
imp space is afforded by a rather peculiar topographic feature. The 
ly gravel occupies an old stream channel cut in a steep gorge of bed 
>ck. Cutting through this old bed is the present more recent creek 
mrse, which has lowered its level many feet below th old channel. 
s a result, there is excellent opportunity for the disposal of tailings, 
he sluice boxes are 5 feet 3 inches wide inside the lining boards, 
welve-inch cube hemlock block riffles are used. Their life is about 
Lree months. It is found that hemlock from this region is tougher 
id wears longer than the fir of the western United States. Attached 
► the end of the tail sluice is an undercurrent. It is divided into 
Lree tables, each 6 by 30 feet, fitted with 6 by 2 by 2 inch block 
ffl.es nailed to a cross strip. The first 4 feet of each table, however, 
fitted with rock riffles, which, though they offer a slight disadvan- 
\,ge in the difficulty of setting up and removal, can be commended 
jcause of their durability and efficiency. The presence of numerous 
rge bowlders required the installation of a tram from the pit to the 
ilings pile. Bowlders less than a foot in diameter which the 
^draulic giant is unable to move are trammed out. Those greater 
Lan a foot m diameter are blasted and then treated in the same 
.anner. It was found that in the lower heavy ground a duty of only 
cubic yard per miner's inch was obtained, whereas in the top ground, 
here the wash is regular and bowlders not abundant, a duty of 3 
ibic yards per inch could be expected. The gold is for the most 
art fine and assays $14.90 per ounce. 
A second pit worked a short distance below the one just described 
iffers in the character of its bed rock. An area about 350 feet long 
f 100 feet wide was piped down through an average depth of about 
) feet, where a clay and cement-gravel bed rock retained the pay. 
and cleaning was necessary, though the taking up of the bed rock 
as no^ deemed profitable. 
About 2 miles above the plant just described, at the mouth of Milk 
ulch, a smaJl tributary of Crow Creek from the northeast, mining 
as in progress by hydraulic methods the greater part of the season. 
