Sheldon


Excerpt from 
ORE DEPOSITS OF THE
JEROME AND BRADSHAW MOUNTAINS QUADRANGLES, ARIZONA
BY
WALDEMAR LINDGREN
WITH STATISTICAL NOTES BY
V. C. HEIKES

1926

http://www.admmr.state.az.us/DigitalLibrary/USGS-Bull/USGSB782JeromeBradshawMtQuads.pdf


WALKER DISTRICT

The Walker district lies in the upper valley of Lynx Creek, 7 miles southeast of Prescott, at an altitude ranging from 6,200 to 7,000 feet. It is one of the oldest camps in the region, as the ore was_ found by the placer miners working up from the lower placers. In the early days ore from many of the outcrops of the oxidized veins was worked in arrastres. Any of the numerous vein croppings will show gold in the pan. Later, mainly before 1910, a considerable amount of deep mining was done on the Sheldon, Mudhole, Amulet, and other properties. In the mint report for 1887 it is stated that 161 tons of ore from the district averaged $10.65 a ton. In Mineral Resources for 1908 it is stated that 142 tons was shipped containing 262 ounces of gold and 455 ounces of silver. Mills treated 450 tons,

which yielded 726 ounces of gold and 446 ounces of silver, with pyritic concentrates of 69 tons containing 160 ounces of gold and 202 ounces of silver. In 1922 the Sheldon mine was reopened with good results and some leasing was done on other properties. Preparations were made to reopen the tunnel to Poland, through which it was in-tended to ship the ore from the Sheldon mine to the Humboldt smelter.
Theveinsaremainlyconfinedtoasmallstockofquartzdiorite(granodiorite)2 miles long and 1 mile wide, intruded in the Yavapai schist on the northwest and in the Bradshaw granite on the southeast. The diorite forms white rounded outcrops. The schist in the lower part of the district contains numerous strong dikes of rhyolite porphyry. One of these at the crossing of Lynx Creek about a milebelowWalkeris200feetwide.Someofthemalsooccurinthegranodiorite. The veins are fissure deposits with quartz and sulphides containing both gold and silver ; there is more free gold in the oxidized material than in depth, The ores have been worked in mills, but the unoxidized ore is now generally shipped to smelters. The dip is steep, and the width reaches several feet; within this thickness there are usually several streaks of quartz rich in sulphides.
The total production of the district from the lode mines is probably not more than $1,500,000. No exact figures are available.

SHELDON MINE
The Sheldon property of 11 patented claims is situated in granodiorite in the southwestern part of the district near the gulch, at an altitude of 6,500 feet. The deposit is a normal fissure vein with

astrike of N. 30° E.; the dip is 81° SE. near the surface, but soon flattens to 70°. The developments consist of a vertical shaft 650 feet deep with drifts extending for several hundred feet on the 250, 450, and 650 foot levels. The old shaft is 500 feet southwest of the present working shaft. The old stopes, from which more or less oxidized ore has been mined, are above the 200-foot level and extend in places to the surface.
The total production of the mine up to 1922 is estimated at about $200,000, but there are no definite data. In 1923 the mine had a large production. Most of the work above the 200-foot level was done prior to 1898; in that year the mine was worked by W. I. Casey. For 20 years lessees had been at work on the property. At the present time it is opened by the Sheldon Mining Co. under the direction of A. R. Ackerman. The shaft makes about 45,000 gallons of water in 24 hours.
The minerals consist of quartz and some calcite, with more or less pyrite, sphalerite, chalcopyrite, galena, and tetrahedrite. The quartz is milky white and contains vugs with small projecting crystals. In the upper levels there is some chalcocite coating the chalcopyrite.
The gold and silver seem to be associated with the galena and tetrahedrite; the chalcopyrite also carries gold. Not more than 30 per cent of the gold and silver in the primary ore can be amalgamated. The sericitic and pyritic granite contains only $2 or $3 to the ton, but the quartzose ore in the shoots yields perhaps $20 to $30. Most of the value of the ore is in gold. Usually it contains but a few ounces of silver to the ton. According to a report by C. H. Dunning the ore now mined is said to average about 2.76 per cent of copper, 3.5 per cent of lead, and $5 in gold and 8.5 ounces of silver to the ton. The best ore developed seemed to be on the 450-foot level north of the crosscut, where the vein in one placewidensto16feet,thoughtheaverageis4to5feet.Thestopelengthissaid to be 700 feet. The same shoot is shown in the north drift on the 650-foot level. Herethereis5feetofsericiticgranodioritewithafewinchesofhigh-gradequartz streaks along the sharply defined hanging wall and footwall. In places the vein closesdowntoaseam.Theshootappearstopitchnorthparalleltothestriations on the walls, which dip 60° in that direction.
The Sheldon vein can be traced for at least half a mile to the southwest and several hundred feet to the northeast. A crosscut is now driven on the 650-foot level in the hanging wall to a parallel vein named the " Capitol."

MUDHOLE MINE
The Mudhole mine lies on the south side of the creek between Walker post office and the Sheldon mine. It is a well-known property, which is reported to have yielded $480,000 in gold and silver, chiefly from 1897 to 1903, although before that time more or less ore was extracted by lessees. In 1900 a mill was built for amalgamation and concentration. It is now reported to be controlled by 'W. I. Casey and C. T. Joslin, of Prescott. The property was idle in 1922, and, in fact, no work has been done on it since 1912. Ore and concentrates were shipped to Humboldt, El Paso, and Needles.
Jaggar and Palache state that at this mine there are two parallel veins, each 6 to 8 feet wide, in gneissoid granite. They also state that between the veins is a white dike of rhyolite porphyry. In part, however, the veins are certainly in a dark dense amphibolitic hornfels with much magnetite, striking N. 60° E., and belonging to the Yavapai schist.
The main north shaft is near Walker post office and is 740 feet deep on the incline of 47°. Apparently most of the workings were in hornfels. The south shaft and tunnel are about 2,000 feet from the main shaft. It is difficult to obtain reliable information as to the conditions on the lowest levels; probably the veins narrowed down in harder rock. The dumps at the tunnel show seams rich in galena and sphalerite with some chalcopyrite and pyrite in bleached hornfels.
The ore is said to have contained from $7 to $15 to the ton in gold and silver, mostly in gold. Shipping ore would contain $50 to the ton. The concentrates were rich, averaging $70 in gold, 5 ounces of silver, and $6 in lead to the ton. Other statements credit these concentrates with an average of $125 to the ton.

AMULET MINE
On the ridge on the Chaparral Creek side, 1 mile northeast of Walker post office, is the Amulet mine, near the contact of the Bradshaw granite and the Yavapai schist. Jaggar and Palache state that
rich silver ore was obtained from a contact breccia between the two formations. Work was done on the Amulet in 1887 to 1891. Highgrade ore shipped is said to have contained 459 ounces in silver and 46 per cent lead.
According to W. I. Casey the Amulet is the extension of the Mudhole veins. The shaft was sunk in recent years to a depth of 200 feet, but little further exploratory work was done. The dump shows mainly quartzite schist with disseminated pyrite and chalcopyrite.

OTHER PROPERTIES NEAR WALKER

The granodiorite contains very many veins, most of them with northeast strike; those west of the Sheldon are said to dip west. Many of them have been worked on a small scale. Among them are the Victory vein, N. 30° W. from the north Mudhole shaft, across the valley toward Groom Creek; the Pine Mountain vein, in the same direction, on which there is a vertical shaft 500 feet deep and which is said to have a shoot of ore 300 feet long; the Black Diamond, 1 mile north of the same point; and the Mark Twain, also 1 mile a little east of north.

PROPERTIES NORTH OF WALKER

Near the wagon road from Prescott to Walker, a few miles from Walker, are several small mining properties. Among them are the Big Dome and the Dinty on the south side of the wagon road, the former said to show a narrow vein of rich silver ore. In the schist there are many pre-Cambrian lenses of quartz but none of much value.
To the east of Lynx Creek is the Jenkins vein, 2  miles northeast of Walker, in amphibolite and diorite; it shows pyrite and chalcopyrite scattered in a quartz lens of pre-Cambrian age. About 1  miles northeast of this property is the Arizona Daisy, reported to contain silver and copper. Three miles northeast of the Jenkins mine is the Banner mine,which is said to have a shaft 325 feet deep with drifts on four levels; the deposit is a quartz vein with gold and silver.