ransome.] PLACER GULCH AND TREASURE MOUNTAIN LODES. 181 
or bunches within the mass of the otherwise low-grade vein. Speci- 
mens of this ore in the possession of Mr. Rasmus Hanson, of Eureka, 
showed the gold scattered through masses of friable spongy quartz, 
and also as implanted crystals on the quartz crystals of drusy cavi- 
ties or vugs. It also occurs embedded in a dark-gray mineral locally 
termed "graphite," but which in reality is molybdenite, 1 in a sulpho- 
bismuthite of lead and silver not specifically determined, and also in 
light-yellow zinc blende. A little native silver sometimes occurs with 
the gold, and some native copper was in the upper workings. The 
general mineralogy of the vein is identical with that of the Sunnyside. 
The Sunnyside Extension (Hanson's) mill, erected in 1889 near the 
head of Placer Gulch, is equipped with a Blake crusher, 20 750-pound 
stamps, dropping inches at 64 to the minute, 4 Gilpin County shak- 
ing tables, and 2 Woodbury tables. The mill was driven by steam 
and has a capacity of 47 tons per day. Ore was brought down to the 
null on a Iluson tramway 2,300 feet in length, with 61 buckets and a 
daily capacity of 175 tons. 
The Mastodon is on the same lode as the Sunnyside Extension mine, 
and lies just northeast of the latter. This claim has never been exten- 
sively developed. It is known to contain some rich silver ore, but 
this is irregularly distributed through the large low-grade lode. A 
mass of this ore, consisting chiefly of an argentiferous sulpho- 
bismuthite of lead in a fine aggregate of quartz and barite, was 
assayed by Mr. Hanson and found to carry 400 ounces of silver. The 
sulphobismuthite occurs as a bright lead-gray mineral, finely dissem- 
inated through the quartz and barite, or in minute ragged prismatic 
crystals. It is not practicable to obtain the mineral in sufficient 
purity and quantity to warrant quantitative chemical analysis, by 
which alone the mineral species could be determined. 
The Mastodon mill was one of the earliest to be constructed in the 
district. In 1899 it had been repaired and was working on ore from 
the Silver Queen mine. Its present equipment is a Blake crusher, 
2 sets of rolls, 1 Huntington, 1 double compartment jig, 2 sets of 
revolving screens, 1 large Bartlett table, 2 "double-deck" Wilfleys, 
and 4 slime tables. Its capacity was said to be 35 tons. 
Silver Queen. — This is a small mine at the head of Placer Gulch 
and about one-fourth mile east of the Sunnyside Extension. The lode 
is somewhat irregular, but appears to strike about N. 10° W. Its dip 
is to the west and unusually flat for this region, being near 40°. Con- 
siderable work has been done, but in a most unsystematic manner. 
The ore seen showed galena, pyrite, chalcopyrite, tetrahedrite, and 
sphalerite, in a gangue of quartz and rhodonite, with a little rhodochro- 
site. It is also said to carry some free gold. This mine has produced 
some good ore, but how much is not known. The silver is said to 
1 T. A. Rickard has erroneously referred to this as graphite, supposing that it aided in precip- 
itating the ore. See The Enterprise mine, Rico, Colorado: Trans. Am. Inst. Min. Eng., Vol. XXVI, 
1897, pp. 976-977. 
