The Brown Monster and Reward mines: Inyo County California.
The Brown Monster-Reward mines are located in Section 3, T. 14S, R. 36E (M.D.M.) at an elevation of 4,500 feet on the western flank of the Inyo Mountains, about 13 miles northeast of Lone Pine in Inyo County, California. They can be reached by driving 5 miles east from State Route 395 on the unpaved Manzanar-Reward Road, to the base of the mountains where several old mining ore bins are located. The road is to the east of the site of the Manzanar World War II internment camp and crosses concrete runways built during the war and used as part of the Civilian Pilot Training Program. These runways were also part of the Western Region Defense Plan, functioning as contingencies in case the West Coast was invaded during the war.
The mines of the Brown Monster-Reward group were some of the earliest gold mines developed in the Owens Valley; at the turn of the century the small town of Reward was located there. in addition to gold deposits, galena and other sulfide veins were discovered. These mines have produced an interesting suite of uncommon colorful crystallized secondary lead and copper minerals.
The earliest history of the Owens Valley is given by Chalfant (1922). No one knows who the first whites were to enter the Owens Valley. it has been suggested that Jedediah Smith passed through the valley in the mid to late 1820s, and there are reports that he discovered placer gold near the north shore of Mono Lake on his return to Salt Lake City. It has also been suggested that in 1833 the mountain man Joseph R. Walker passed through the valley while on an expedition which he led from Salt Lake City, Utah to Monterey, California. The first well-documented party of whites to enter Owens Valley was a wagon train led by Walker in 1843. The group of about 50 was organized in Independence, Missouri by Joseph Chiles and was met in Fort Laramie, Wyoming by Walker, who guided them to Visalia, California and the Gilroy Rancho after many ordeals. it has been speculated that his route through the Owens Valley at this time was based on his earlier travels in 1832-1833. An expedition led by John C. Fremont which left from Bent's Fort on the Oregon Trail met up with Walker and Richard Owens in 1844, and it was Fremont who named Owens River, Owens Valley and Owens Lake in honor of Owens' abilities. This party passed through Owens Valley in 1845 after having traveled through the San Joaquin Valley and crossing the Sierra Nevada.
Following the discovery of gold at Sutter's mill, near Sacramento in 1849, the gold rush sparked exploration and prospecting for gold throughout much of the Sierra Nevada and beyond. In 1859 Cord Norst discovered placer gold in Mono Gulch, in the northern part of Owens Valley, and this may have been the site where Jedediah Smith discovered gold in the 1820s. This sparked the "Mono diggings" and the formation of the short-lived settlement of Monoville.
By 1859-1860 several parties had begun to prospect the southern Owens Valley, including the Hill party, which established temporary headquarters near Lone Pine and which prospected Mazourka Canyon. In 1860 the party of Dr. Darwin French (the Darwin mines and Darwin Falls were named after him), which included Dennis Searles, had discovered silver-lead ores at Old Coso south of the Owens Valley.
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On March 4, 1860 the New World Mining and Exploration Company, consisting of about 20 men led by Colonel H. P. Russ, left San Francisco with the purpose of prospecting the Owens Valley and adjacent areas. A second group, headed by Dr. S. G. George, which left from Visalia, met the party at Walker's Pass and the combined group entered Owens Valley, with one party exploring eastward from Owens Lake. A camp was established on the banks of the Owens River, a few miles southeast of the present town of Independence, from which Dr. George spotted the Union vein with his field glasses. Russ and George examined the outcropping, which was encouraging, and they moved camp nearer to the lode and organized the Russ Mining District on April 20, 1860. The claims located at that time included the Union, Ida, and Eclipse, which was later named the Brown Monster. During these early times the local Paiute Indians were curious and generally friendly. The Indians indicated that the mountain to the east of the valley was named "Inyo" which was interpreted to mean "the dwelling place of the great spirit."
By 1861, not only had prospectors begun to enter the Owens Valley but cattlemen also arrived, bringing their herds with them, and decided to winter in the area. The winter of 1861-1862 proved to be the most severe in many years, with 54 straight days of either heavy rain or snow. This created hardships for everyone, and on occasion the Indians would slaughter a steer. This was tolerated for some time but finally the cattlemen murdered several Indians in retaliation. After a brief truce the situation deteriorated rapidly and a full-blown Indian war erupted. Lone prospectors were particularly at risk of being ambushed, property was destroyed, and parties as large as 13 had been massacred.
By May of 1862 the Indians were in nearly undisputed possession of the Owens Valley. As a result, there was an appeal for military protection, and on June 12, 1862 a Colonel Evans left Fort Latham, near Los Angeles, with 157 men as part of the Mono and Owens River Military Expedition. On July 4, 1862 they settled into a site in the Owens Valley which they named Camp Independence, because of the occasion, and which later became the town of Independence. The soldiers not only attacked the Indians but also destroyed their food caches. A truce and treaty were quickly established, and during the remainder of 1862 work began at the Eclipse mine, with R. S. Whigham as superintendent.
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A prospecting soldier discovered gold in the range northeast of the Camp, and when samples sent to San Francisco proved rich, the San Carlos Mining and Exploration Company was organized. On September 24, 1862 Henry G. Hanks (after whom hanksite was later named), who was to become the first state mineralogist in 1880, was sent to investigate, and he became the assayer for the San Carlos mine.
The truce with the Indians was tenuous at best and skirmishes would periodically break out. Henry Hanks, in his correspondence to the President of the San Carlos Company in 1862, noted that he and a Captain Anderson took six rifles and ammunition down to the Union mine to protect the mill, and that several nights earlier Indians had burned the haystack and camp at the mine. In July 1863, after the Kern massacre and persistent destruction of their food caches by the soldiers, 400 Indians surrendered and a total of 900 Indians were relocated to the San Sebastian reservation near Fort Tejon.
During periods when conflicts with the Indians were less frequent, and it was perceived that the warfare had ended, settlers continued to enter the Owens Valley and mine development continued. In a letter from San Carlos to the San Francisco Alta California in September 1863 it was noted: "In the Russ district several companies are at work. The Eclipse is turning out rich ore and is of great extent. If it is not the richest mine in all of California we are all mistaken ..." It is not known how true this statement was, but for the purposes of attracting investors it is assumed one always has "the richest mine in all of ..."
At this time several small communities, which no longer exist, sprang up. The closest to the Eclipse mine was Bend City, so named because it was situated on a bend in the Owens River. To the north were San Carlos and Chrysopolis. Both Bend City and San Carlos consisted of 60 or more adobe dwellings, including several hotels, dry good stores and saloons, and each had a ferry to provide access across the Owens River to the mines and prospects to the east in the Inyo Mountains. Indian raids resumed during the mid-1860s, and in 1865 the Union mill was burned. While many inhabitants fled the area, some that remained organized a militia and took part in the Owens Lake massacre in January 1865, where dozens of Indian women, children and unarmed men were murdered. With the end of the Indian war around 1867, settlement and development of the Owens Valley resumed. The total loss of life as a result of the war was about 60 whites and 200 Indians.
With the founding of the town of Independence in 1865, at the former site of the camp, the communities of Bend City and San Carlos quickly fell into obscurity. In 1870 Isaac Friedlander applied to patent the Eclipse mine (Chalfant, 1922) and a six-stamp mill had been constructed at the site of the old Union mill on the banks of the Owens River. Much of the following history comes from numerous accounts in the Inyo Independent, a local newspaper.
In 1870 the mine was purchased from the Union Company by a group of English investors, the Eclipse Gold Mining Company, for $150,000. Goodyear visited the mine in 1870 and published a description in Irelan (1888). At that time, Captain Eudey, who was superintendent of the works, was awaiting arrival of mill machinery from England. The mine consisted of three levels which followed a quartz vein. "Much of it is very cellular, filled with cavities containing crystals of calcite, etc. ... Some of it contains beautiful crystals of perfectly transparent quartz ... fine particles of free gold may be seen quite plentifully scattered through some jaspery rock. ..." Later in 1871 a 1.5-mile tram was completed, a 20-stamp mill was operational and a ditch to supply water from the Owens River was deepened.
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On March 26, 1872 a strong earthquake (around magnitude 7.6) struck near Lone Pine, killing 27 people there, while killing one person and injuring another at the Eclipse mine. Most of the adobe dwellings in Lone Pine, Bend City and San Carlos were destroyed, including those at the Eclipse mine (Chalfant 1922). Fanciful accounts of the quake were reported in the local newspapers. "Immediately following the great shock, men whose judgment and veracity is beyond question, while sitting on the ground near the Eclipse mine, saw sheets of flames on the rocky sides of the Inyo Mountains but a half mile distant. These flames, observed in several places, waved to and fro apparently clear of the ground, like vast torches; they continued for only several minutes." Later that year the mine was beset by claim jumpers, and rumors of mismanagement were circulating in the London Mining Journal.
In 1874 Captain Eudey brought eight to ten English miners to work at the Eclipse. By 1875 the mill had been completed along with a 3-mile tramway that connected the mine with the mill. In 1876 the Eclipse mine shipped $18,346 worth of bullion and by 1877 an additional ten stamps were added to the mill, bringing it to a total of 30. By 1877 Captain Eudey had been replaced as manager, and the mine ran into such severe financial difficulties that it had to be sold. This ended the connection of the London Company with the enterprise, since they were forced to sell it in order to pay creditors, primarily local merchants (one of whom was A. W. Eibeshutz), who may have been in league with Captain Eudey. Captain Eudey then became mine manager once again, and made the mine operational. It was renamed the Brown Monster mine, and a 30-stamp mill was constructed 4 miles from the mine, on the banks of the Owens River.
The main Eclipse vein was discovered in 1878 (Knopf, 1914). The mill, which had a crushing capacity of 45 tons of ore a day, was connected to the mine by a railroad and was driven by water carried from the Owens River in a 6-mile ditch (Irelan, 1890). In 1880 the Carson and Colorado narrow gauge railroad was incorporated, and by 1883 the line extended from Carson City, Nevada to the Owens Valley, where it ran along the east side of the valley from Laws to Keeler on the north shore of Owens Lake. The railroad was only a mile from the west flank of the Inyo Mountains, providing easy access to the local mines, including the Brown Monster and Reward. Similarly a series of canals that were constructed ran along the east side of the Owens Valley and provided water to the mines from the Owens River.
In 1882 patent applications were submitted for the Brown Monster mine by A. W. Eibeshutz and for the nearby Hirsch mine (later renamed the Reward) by Nathan Rhine, another local merchant. Rich ore was supposedly being taken out of the Hirsch by Captain Watt and the Furguson brothers. Eibeschutz spent considerable money suing the English mining company and defending himself. As a result, he had little capital to invest in the Brown Monster mine, and by 1885 the mine was being leased to Tom Bastion and the mill had fallen into disrepair.
For the next ten years there is little to no mention in the local newspapers of mining activity at the Brown Monster mine, or anywhere else in Inyo County. By 1896 the Hirsch mine had been renamed the Reward, the shaft was down 115 feet, and 25 men were employed there by the company. In 1902, A. W. Eibeshutz sold the Brown Monster mine to some Los Angeles investors, who probably were also the owners of the Reward mine, for $15,000. At this time a 14-foot ledge containing high-grade ore ("... coarse gold, like wheat grains ...") was developed.
In 1903 the 30-stamp mill was dismantled and replaced by a 20-stamp mill which was located at the mine site and connected to the upper workings by a gravity tram (Knopf, 1914). This new mill and a 120-kilowatt generator, powered by a small waterfall in the William Penn Colonial Association ditches, cost $80,000 and a small school house was also built at a cost of $2,500. During this time a small town developed which, in addition to the school house, had a U.S. Post Office from 1900-1906.
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In 1910 the Carson and Colorado Railroad was taken over by the Southern and Pacific, and the narrow-gauge engines were affectionately nicknamed the "Slim Princess" (Ferrell, 1982). After some neglect, due to lack of adequate power for profitable development, the mine was taken over by A. J. McCone and Associates in 1910. In 1911 the mine facilities and mine were overhauled and an electric transmission line was constructed across Owens Valley in order to supply power. In 1912 the mine was closed in order to install a cyanide plant; however, there was also a pending change of ownership, and evidently the mine remained idle until 1935.
The Brown Monster was leased and worked by T. L. Brite (or Bright) of Independence for most of the period from 1936 to 1951. The owners were Guy Eddie and Charles De Chase of Los Angeles. The property consisted of two patented claims (the Reward and the Brown Monster) and six general claims (including the Eclipse, Hidden Treasure, Hirsh and Telescope groups). The Hirsh is located a little above the Brown Monster mine and consisted of a 100-foot-long tunnel with a 200-foot drift running along on the ledge, from which three winzes were sunk. The gold-bearing quartz vein proved to be 4 to 8 feet thick and also carried argentiferrous galena.
From April 1935 to February 1936, some 2,000 tons of ore averaging $25 per ton of gold was extracted from the Brown Monster (Tucker and Sampson, 1938). From March to August 1936 the Reward was leased by Monte Carlo Mines, Inc. and ore was shipped to the Mount Whitney/Union mill for treatment. However, there was insufficient recovery to justify continued operation. In 1938 ten men were employed at the Brown Monster mine; ore, said to carry $25-40 per ton of gold, was shipped to the Burton Brother's mill at Tropico in Kern County (Tucker and Sampson, 1938).
From 1940 to 1942 the mines, which were owned by Basil Prescottt of Beverly Hills, were subleased to the Golden Queen Mining Company which undertook considerable exploration. Several hundred feet of drifts and crosscuts were driven, and diamond drilling work was done at both the Brown Monster and the Reward. Ore was shipped to the Golden Queen mill in Mojave but results were not encouraging. In 1948 veins carrying lead, silver and gold were discovered in the upper levels of the Reward and for a while 10 tons per day, assaying at $100-150/ton, were shipped to the American Smelter and Refining Company in Selby, California (Norman and Stewart, 1951). As of 1951 a small mill had been constructed to concentrate lower-grade ore and three men were employed there.
In the early 1980s the workings were reactivated by International Recovery of Los Angeles, with Ted Youngquist as mining engineer, and a modern two-compartment mine tunnel was cut into the lower workings of the Brown Monster mine from the north side of the ridge, opposite from the original inclined shaft (California Mining Journal, 1983). This tunnel is on an approximately 25[degrees] incline and has several side tunnels and horizontal workings at its base. These tunnels appeared to follow and intersect some of the original lower workings but, in general, only penetrated barren ground. Supposedly stoping was performed in the upper levels and ore was transferred by gravity along chutes to the new haulage tunnels. The ore was processed at the Firestone mill east of Independence, but there was little recovery. During this time period there was extensive machinery on the premises, but today it has all been removed and the site is abandoned. The two-compartment 25[degrees] incline is a popular attraction for people who enjoy the thrill of actually being able to drive their vehicle underground.
At present, many of the picturesque original ore chutes and bins and the aerial tramway still remain in the gulch, giving the area its historic character, but little remains of the town of Reward, with the exception of a few minor stone building foundations and a concrete slab. In 1959 the Southern and Pacific (formerly Carson and Colorado) narrow-gauge railroad line, which was the last commercially operated narrow-gauge line in the country, was reclaimed and the Owenyo Road marks the location of the old railroad bed. The remains of the old canals that once brought water to the mines along the east side of the Owens Valley, before the Los Angeles aqueduct was constructed, can still be seen in places as long, shallow, mud-crack-filled depressions.
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GEOLOGY AND MINE WORKINGS
The Brown Monster and Reward mines are located at the western base of the Inyo Mountains in a block of metamorphosed limestone of the Early Permian Lone Pine Formation (Stone, et at., 2000). The limestone is adjacent to the Middle Jurassic Pat Keyes Pluton and some minor Jurassic diorite dikes. This report will follow the convention of Knopf (1914), who referred to the workings north of the narrow, steep Reward gulch as the Brown Monster mine, and those on the south side as the Reward mine. The workings of the two mines are separated by a fault or shear zone located in the gulch.
The main Brown Monster inclined shaft is located in Reward gulch, just above an old ore chute. The portal is rather obscure now because debris from the Reward dump has washed down the gulch and partially fills the entrance (you must crawl on your hands and knees to enter or use a side entrance). The shaft, which follows a fault that strikes N 40[degrees] E, is gently inclined (25[degrees]) near the surface but steepens (to 50[degrees]) with depth, with side tunnel levels at 60, 96, 200 and 250 feet (Tucker and Sampson, 1938). The various levels are partially connected by inclined stopes which follow a quartz vein that averages 6 feet in width. At the lower level, a series of ladders connect with the 1980s tunnel/workings that were driven from the north side of the ridge. The gold ore was found in quartz veins that locally contain sulfides and cut across marble. There are also a number of surface workings about 100 feet above the portal which were connected to the base of the gulch by an aerial tramway.
The main Reward and Brown Monster tunnels were supposedly connected by a 50-foot-long tunnel. This connection could not be found recently, but several tunnels in the Brown Monster mine that appeared to extend in the right direction were found to be either caved or silted closed and filled with debris that has cascaded down the steep Reward gulch. The Reward vein striking N 40[degrees] W and dipping 40[degrees] NE, is about 6 to 8 feet in thickness and consists of milky quartz. The lowest Reward tunnel, which was once connected to the main Brown Monster incline, was driven 1,200 feet N 55[degrees] E, for 650 feet to the vein, and then drifted southeastward 800 feet (Tucker and Sampson, 1938). About 50 feet above the lowest tunnel is another, which was driven southeastward for 800 feet. At about 25-foot intervals above the second tunnel are four more tunnels driven from 300 feet to 700 feet. Three of the tunnels are connected by a large, continuous, inclined stope, which can be accessed by a tunnel (4th-5th above the lowest) which opens to the surface. It had been difficult to reach this tunnel because of a small dry waterfall, but in 1998 the collapse of a portion of the Reward dump into the gulch created easier access. This tunnel and the Reward dumps are located about 70 feet above the Brown Monster main inclined tunnel. From the lowest part of the large inclined stope a ladder leads to the lower tunnels, but these were not explored by the author. Above the dumps and access tunnel for the Reward mine are several other small workings which follow the surface outcrop of the vein.
The gold ore in both the Reward and Brown Monster mines occurs in thick (to 6 feet) milky quartz veins that dip 25[degrees]-50[degrees]. From 1889 to 1951 the Reward mines produced $600,000 (19,370 oz.) of gold, 102,600 oz. of silver, 30,900 lb. of copper and 203,300 lb. of lead (Conrad et al., 1987). Primary sulfide minerals in the quartz veins include pyrite, galena, chalcopyrite and minor sphalerite. More recently covellite has been identified (R. Thomssen, personal communication, 2004).
An interesting suite of secondary lead and copper minerals also occurs in the quartz veins and adjacent marbles and limestones. These, first briefly described by Knopf (1914), included linarite, caledonite, anglesite, wulfenite, hemimorphite and cerussite.
Minerals in this report were identified by X-ray diffraction (XRD) or energy dispersive X-ray spectroscopy (EDXS) in the scanning electron microscope (SEM). All figured specimens, were photographed by, and are in the collection of the author. All of the minerals that will be described have been collected from the underground workings during numerous visits from 1997-2001. At that time there was very little of mineralogical interest exposed on the dumps of the various mines and prospects; however, since then there has been considerable effort to expose buried portions of the Reward dump. It is not known whether this has produced any new material different from what has been collected underground.
On the north-facing slope of the ridge that separates the large drive-in tunnel and the main upper portal of the Brown Monster mine, a skarn containing large (1-3 cm) green diopside crystals and brown vesuvianite crystals in blue calcite was observed. The micromineralogy of the Brown Monster and Reward mines has been documented previously by Adams (1999 and 2000, respectively). The purpose of these earlier reports was to document newly described species from the mines and to present SEM photomicrographs of the more unusual microminerals. The following is a more comprehensive description of the minerals found at the two mines, with particular attention paid to minerals of interest to collectors, and to discoveries made since 2000.
Colorless, transparent, complex crystals (to 2.5 mm) of anglesite occur with brochantite, caledonite, chlorargyrite and linarite in cavities at the Reward mine. At some locations the anglesite crystals have a frosted appearance, and at others the anglesite encloses remnants of linarite.
Plumbian apatite-(CaF) has been found as overgrowths on mimetite prisms (to 1 mm) in a few specimens from the Reward mine.
At the Reward mine some of what was originally assumed to be tsumebite is more yellow-green in color than is typical for that mineral. These specimens (to 0.2 mm crystalline aggregates), are actually arsentsumebite, since the As:P ratio can be as high as 2:1. They occur in an early assemblage and are usually associated with brochantite, perite and other bismuth minerals, plattnerite and minute wulfenite crystals, which they commonly overgrow.
Botryoidal gray-green plumbian austinite crystals (to 0.5 mm) have been found coating fracture surfaces with mimetite in the upper stope of the Brown Monster mine.
Massive azurite is found with acicular malachite in one of the upper workings (7th level) of the Reward mine.
Yellowish, minute (0.1 -mm) scaly bismutite and bismoclite crystals occur as an early constituent in some vugs with chlorargyrite, arsentsumebite and wulfenite, at the Reward mine.
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Brochantite is one of the more common secondary minerals in the Reward mine. It occurs in cavities and on fracture surfaces in a variety of crystal habits ranging from blocky, near equant crystals (to 1 mm), to flat blades or tablets and lustrous, transparent, dark green radiating acicular sprays (to 3 mm). Commonly the brochantite is associated with cerussite, chlorargyrite, linarite, caledonite and leadhillite. Chrysocolla is often found as pseudomorphs after brochantite crystals.
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Minute (to 1.5 mm) yellow-green distorted octahedrons and cuboctahedrons of bromargyrite have been found on white micro-crystalline drusy quartz, cerussite and plattnerite in a localized area near the portal of the Brown Monster mine. The bromargyrite contains significant amounts of chlorine.
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At the margins of the main quartz vein in the Reward mine the enclosing limestone has been recrystallized to coarse-grained marble, and veins of calcite crystals (to 4 cm), with habits ranging from platy to blocky, are common in several areas. At the Brown Monster mine calcite crystals (to 1.5 cm) lining fractures in marble are also common. From vein to vein there is a wide variety in the habit of the calcite crystals, which range from nearly equant "pseudooctahedral" crystals, to stacks of subparallel plates, to dogtooth crystals and fish-tail twins. Late-stage colorless, transparent calcite crystals (to 6 mm), as simple rhombs to tapered tablets, can also be found growing in some of the cavities associated with cerussite and other secondary lead minerals.
Caledonite occurs at the Reward mine as striated, green-blue, flat bladed crystals (to 1 cm) lying parallel with fracture surfaces in milky quartz and in vugs. Linarite, brochantite, anglesite and leadhillite are commonly associated. Commonly the caledonite has an olive-green appearance as a result of having overgrown chlorargyrite crystals. At the Brown Monster mine small caledonite crystals (0.5 mm) occur with linarite near altered galena pods.
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At the Reward mine cyclic twins of cerussite were one of the earliest secondary minerals. Sometimes crystals can still be found that have a thin coating of chrysocolla but it is more common to find epimorphs of micro-drusy quartz after the cerussite. These typically are hollow shells after either cyclic or V-shaped twins (to 5 mm). A second, relatively late generation of cerussite is also found. These crystals (to 3 mm) usually appear as colorless and transparent to white, flattened, subparallel growths which often overgrow brochantite. They are very difficult to distinguish visually from leadhillite but typically leadhillite is only found when caledonite is present. Cerussite has also been found as large (1 cm) botryoidal coatings in rubble. At the Brown Monster mine one area near the portal contained resinous masses of cerussite which contained cavities lined with euhedral crystals, many as V-shaped twins (to 8 mm). The cerussite crystals have a thin coating of white, micro-drusy quartz which gives them a frosted appearance; they are usually associated with plattnerite and bromargyrite.
Small (1 mm) masses of pale blue, transparent chalcanthite are rare but have been found in the Reward mine. Identification was made by Raman spectroscopy.
Olive-brown corroded crystals and distorted octahedrons (to 1 mm) of chlorargyrite occur as an early-stage mineral in vugs at the Reward mine. The chlorargyrite contains significant amounts of bromine, approaching 50 atom percent.
Pseudomorphs of chrysocolla after brochantite (to 2 mm) are relatively common at the Reward mine. Chrysocolla also forms thin coatings on quartz pseudomorphs after cerussite. Chrysocolla pseudomorphs (to 5 mm) after a bladed or acicular mineral (malachite?) and a mineral which formed small (to 2 mm) lenticular crystals were also found in an isolated occurrence in a pillar. Chrysocolla pseudomorphs of botryoidal malachite (to 4 mm) with hemimorphite have also been found in float. Pseudomorphs after platy rosettes (to 8 mm) have also been found.
Minute, golden brown to chocolate-brown corkite crystals (0.25 mm) are uncommon at the Reward mine. Some of the crystals form rounded aggregates. They typically occur with other phosphates, including tsumebite and pyromorphite.
Descloizite has been found at the Brown Monster mine, associated with mottramite. It is brown in color and tends to form larger crystals (to 0.25 mm) than the mottramite, which is typically more micro-botryoidal. Micro-fibrous cuprian descloizite has also been found covering small quartz crystals.
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An intermediate composition in the duftite-conichalcite series has been found at both the Reward and Brown Monster mines, but is not common. At the Reward mine green botryoids (0.5 mm) of calcian duftite were found associated with uncommon elongate white mimetite prisms (to 1 mm). Green botryoidal duftite-conichalcite (2-3 mm) has also been found associated with mimetite at one location in the Brown Monster mine. It is very similar in appearance to green mottramite found at another location in the mine.
At the Brown Monster mine, groups of brown bladed fornacite (to 0.4 mm) are relatively uncommon and are found on drusy quartz or lining fractures in marble. At the Reward mine, fornacite occurs with mottramite, mimetite, vanadinite and wulfenite on fractures in marble. It has also been found in float with minute white sprays of pyromorphite, hemimorphite and chrysocolla after malachite.
Crystallized goethite is relatively uncommon at the Reward mine. It is usually found as minute (0.5 mm) golden radiating sprays. Transparent violet-brown plates (to 0.2 mm) are less common. At the Brown Monster mine goethite and kaolinite form casts after a bladed mineral, most likely hemimorphite.
With all the colorful secondary minerals at the Reward and Brown Monster mines one can easily lose sight of the fact that the mines were gold mines and that gold can still be found there today. A few small flakes (to 1 mm) of gold have been found in milky quartz in the Reward mine, associated with brochantite and linarite. The gold has been described as being most plentiful in the more jasper-like quartz rock (Irelan, 1888).
Rare curved fibers (to 1 mm) of gypsum have been observed with brochantite at the Reward mine.
Hemimorphite [Zn.sub.4][Si.sub.2][O.sub.7][(OH).sub.2] [H.sub.2]O
Bladed hemimorphite crystals (to 2 cm) were found in the Reward mine in one difficult-to-reach occurrence (2.5 meters up the side of a pillar). While some of the crystals were rather large it was difficult to collect undamaged terminated crystals because they tended to bridge the whole width of cavities in hard quartz. Occasionally, radiating sprays (to 7 mm) from this occurrence could be collected intact. These are commonly overgrown by micro-drusy quartz and colorless, transparent discoidal calcite crystals. Smaller sprays of hemimorphite, associated with acicular microcrystals of pyromorphite and chrysocolla after malachite were sometimes found in rubble in the stope. Colorless, transparent bladed hemimorphite crystals (to 3 mm) occur at the Brown Monster mine associated with mimetite and wulfenite. At one locality hemimorphite crystals to 2.5 cm have been found (F. DeVito, personal communication, 1998). Radiating groups of hemimorphite up to 1 cm in diameter have been reported from the fifth level of the Brown Monster mine (Knopf, 1914).
At the Brown Monster mine orange to tan crusts of jarosite, some with brown spheres (0.5 mm) of mottramite, are occasionally found with mimetite on fracture surfaces in gray limestone. Plumbojarosite has also been identified in some of this material (R. Housley, personal communication, 2004).
Minute (0.2 mm), pale yellow-green square plates of kettnerite are rare as part of an early bismuth-containing assemblage in the Reward mine.
At the Reward mine, leadhillite occurs as colorless, transparent, flattened, subparallel crystals (to 7 mm) on quartz associated with linarite, brochantite and caledonite. Typically it is only found where caledonite is present. Fourier transform infrared (FTIR) spectroscopy was used to distinguish between leadhillite, anglesite and cerussite. At one location in the Brown Monster mine massive leadhillite cleavages are relatively common (F. DeVito, personal communication, 1998).
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Dark blue linarite crystals occur locally along fractures in white quartz veins at the Reward mine. The crystals (to 1.2 cm) are usually flattened and lie parallel to the fracture surfaces. Specimens to 8 X 10 cm consisting of groups of crystals covering fracture surfaces have been recovered. Brochantite, cerussite, anglesite, leadhillite and caledonite also occur with linarite in various combinations. In addition to forming on fracture surfaces, a similar assemblage has rarely been found in vugs and cavities. At the Brown Monster mine small linarite crystals (0.5 mm) occur with caledonite near altered galena pods.
At the Reward mine, fibrous to feathery malachite crystals occur as coatings on pseudomorphs of brochantite after chrysocolla, and radiating aggregates to 3 mm; it is a late stage mineral. Acicular malachite also occurs lining cavities in the upper workings (7th level), where it is found with massive azurite.
Mimetite is relatively common at the Brown Monster mine, in a variety of habits and associations. In quartz veins near the marble contact mimetite occurs as elongated lemon-yellow prisms (to 1.5 mm) which grade into vanadinite. In one area crystalline mimetite forms radiating aggregates of yellow acicular crystals (0.2 X 0.15 mm) that protrude from fracture surfaces in gray limestone in the ceiling of the slope. Wulfenite is commonly associated with the mimetite, and fracture surfaces to 3 X 7 cm have been found covered with microcrystals. On some fracture surfaces the mimetite has a feathery appearance. In one area, where it is associated with mottramite, the mimetite displays a wide variety of habits ranging from colorless, transparent prisms, to very acicular clusters, to nearly equant crystals. One small occurrence of elongated cream-colored mimetite prisms (to 1 mm) with green botryoidal duftite-conichalcite (0.5 mm) was found in the Reward mine. Mimetite crystals, similar in appearance and associations to those at the Brown Monster mine, are also found at one location on fracture surfaces in marble at the Reward mine. At the Reward mine the white mimetite is usually pure, whereas the yellow to orange mimetite typically contains vanadium and can grade into arsenian vanadinite.
At the Brown Monster mine, mottramite is relatively common at certain locations. It forms botryoids and crusts that range in color from pale yellow-green to tan, brick-red and chocolate-brown. It is commonly associated with mimetite and wulfenite. Locally it has been found as dark brown botryoidal coatings to 2 mm thick and as individual brown spheres (to 1 mm) associated with dark reddish brown vanadinite. Evidence of multiple episodes of growth is relatively common. Mottramite has been observed overgrowing mimetite, quartz and calcite crystals. A similar occurrence is found in a localized vanadate assemblage in the Reward mine. Small spheres (0.25 mm) of brown calcian mottramite have been found on rubble near the portal to the Reward mine.
Minute plates (0.2 mm) of pale brown perite occur as an early mineral with elongate pyramidal wulfenite, arsenian tsumebite and plattnerite in the Reward mine.
In one area of the Brown Monster mine, minute (0.5 mm) white prisms of what was originally assumed to be calcian pyromorphite were found associated with rosettes (1 mm) of brown fornacite. The composition of these crystals is consistent with phosphohedyphane (A. Kampf, personal communication, 2007).
Plattnerite has been found at the Brown Monster mine in several habits. Locally it forms dense clusters of thin tablets (0.01 X 0.15 mm) found on white micro-drusy quartz-covered cerussite crystals. Veins in marble lined with micro-drusy quartz casts after a tabular or bladed mineral (calcite) commonly have a sooty appearance as a result of being dusted with very minute (0.02 X 0.10 mm) elongated prisms of plattnerite. At the Reward mine plattnerite crystals (to 0.2 mm) occur with perite, arsentsumebite and wulfenite. Under the scanning electron microscope the plattnerite sprays can be seen to have an unusual conical shape, expanding from a narrow base.
Casts (to 3 mm) of goethite and kaolrnite after a bladed mineral have been found found at the Brown Monster mine, on fracture surfaces in limestone. Associated with the casts are minute (0.05-0.10 mm) groups of white plumbogummite crystals and occasional brown spheres of mottramite. Some minute plumbogummite crystals were also found with jarosite crusts and mimetite, but these could only be identified by EDXS in the SEM. Overgrowths of brown plumbogummite on spherical corkite groups (to 0.5 mm) have occasionally been found at the Reward mine.
At the Reward mine plumbojarosite occurs as small (to 0.25 mm) brown to golden plates with chlorargyrite in vugs containing an early mineral assemblage. Plumbojarosite has also been reported from the Brown Monster mine (R. Housley, personal communication, 2004).
At the Reward mine, white radiating groups of pyromorphite crystals (0.5 mm) were occasionally found with tsumebite and corkite. Gray, rounded, hexagonal prisms of calcian pyromorphite have also been found with corkite, and minute white acicular sprays of pyromorphite have been found with hemimorphite and chrysocolla after malachite in rubble in one of the stopes.
Cavities lined with quartz crystals (to 9 cm), are relatively common in the veins at the Reward mine but the crystals tend to be tectonically broken and heavily iron-stained (including fracture surfaces). White to gray calcite crystals (to 5 mm) and gray-blue chalcedony are occasionally found associated with iron-stained quartz crystals. The chalcedony fluoresces bright green in ultraviolet light.
At the Brown Monster mine, late-stage micro-drusy quartz commonly overgrows the secondary minerals; cavities lined with large crystals are rare. As early as 1870 "beautiful crystals of perfectly transparent quartz" were described from the Brown Monster mine (Irelan, 1888).
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At the Reward mine, tsumebite, as pale apple-green crystalline aggregates (to 1 mm), is found eidier by itself or associated with other phosphates such as minute, elongated prisms of white pyro-morphite (to 0.5 mm) and small olive-brown crystals of corkite. The tsumebite is usually associated with small gray marble inclusions in the quartz vein. Areas up to 3 x 3 cm covered with tsumebite have been recovered.
At the Brown Monster mine, vanadinite occurs as transparent reddish brown crystals (to 2 mm) associated with mottramite and wulfenite. The dark red-brown crystals typically have steep pyramidal terminations, many of them with pale yellow tips. These crystals typically have a second generation of oriented acicular vanadinite growing from the tips. In one small area the vanadinite crystals were found perched on micro-bladed deep red mottramite, while in anomer area the pale orange mottramite forms crusts (molds) that cover vanadinite and calcite crystals. Late-stage microcrystal-line drusy quartz also forms molds covering 2 to 3-mm prismatic vanadinite crystals.
Vanadinite crystals with appearances and associations similar to those at the Brown Monster mine are also found at one location near the portal of the Reward mine. At both mines the darker red varieties tend to be arsenian vanadinite while the paler orange to yellow crystals are vanadian mimetite--but exceptions exist.
Wulfenite is relatively common at the Brown Monster mine where it occurs as bright orange to yellow microcrystals in a variety of habits ranging from thin tablets (to 2 mm), to elongate simple tetragonal prisms (to 2 mm), to equant crystals (to 1 mm). The wulfenite is commonly associated with mimetite and mottramite.
Wulfenite is also common at the Reward mine, where pale orange crystals are occasionally found associated with brochantite and are often found as overgrowths on arsentsumebite. Most crystals are simple elongate tetragonal prisms (to 3 mm), although elongated pyramidal and equant crystals also occur. More complicated tetragonal prisms were also found associated with brochantite at one location. Pseudomorphs (to 3 mm) of arsentsumebite and chrysocolla after wulfenite have rarely been found. Orange platy wulfenite crystals associated with vanadates (mimetite and mottramite) have been found at one location; the specimens are indistinguishable from those from the Brown Monster mine. Orange wulfenite plates (to 4 mm) partially or totally encased in colorless, transparent discoidal calcite crystals have also been found associated with hemimorphite.
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Both the Brown Monster and Reward mines have produced a nearly indistinguishable assemblage of lead arsenate, molybdate and vanadate minerals including fornacite, mimetite, mottramite, vanadinite and wulfenite. The size and habits of the crystals are nearly identical and it is impossible to identify the source based on appearance. The crystals are mostly associated with fracture surfaces and thin quartz veins in marble. In both mines zinc minerals (primarily hemimorphite) are present, but are limited in distribution. While the Brown Monster and Reward mines are in close proximity, a fault or shear zone separates them so the exact relationship between the two quartz veins remains uncertain.
The Reward mine has produced a more extensive suite of lead and copper sulfates and phosphates which appears to be more associated with galena in thick quartz veins. These minerals show interesting changes in chemical history. In a localized vuggy zone, cerussite appears to be one of the first secondary minerals to have formed. This was followed by a mixed group of lead and bismuth minerals including chlorargyrite, wulfenite and perite followed by arsentsumebite. This introduction of minor amounts of phosphate minerals was followed by a much more significant deposition of copper and lead sulfate (and minor phosphate) minerals, such as brochantite, linarite, tsumebite, corkite and pyromorphite. This phase also included the introduction of mixed carbonates such as caledonite and leadhillite, leading finally to a simple assemblage of copper carbonates and silicates (malachite and chrysocolla). During these several chemical transitions, earlier minerals frequently became unstable, leading to the formation of interesting pseudomorphs.
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The Eastern California Museum is gratefully acknowledged for searching their archives and for making early photographs of the Eclipse mine available for study and publication. The Laws Railroad Museum is also thanked for searching their files and sharing information on the Brown Monster and Reward mines. Many of the mineral images are the result of combining a series of digital through-focus images using the free software CombineZ.
ADAMS, P. M. (1999) Microminerals from the Brown Monster mine, Inyo County, California. Mineral News, 15, No. 11.
ADAMS, P. M. (2000) Microminerals from the Reward mine, Inyo County, California. Mineral News, 16, No. 5.
ANONYMOUS (1983) California Mining Journal, 53, 12-14.
CHALFANT, W. A. (1922) The Story of Inyo. Chalfant Press, Bishop, California.
CONRAD, J. E., KILBURN, J. E., BLAKLEY, R. J., SABINE, C., CATHER, E. E., KUIZON, L., and HORN, M. C. (1987) Mineral resources of the southern Inyo Wilderness Study Area, Inyo County, California. U.S. Geological Survey Bulletin 1705-B.
FERRELL, M. H. (1982) Southern Pacific Narrow Gauge. Edmonds, Pacific Fast Mail.
IRELAN, W., Jr. (1888) Eighth Annual Report of the State Mineralogist. California State Mining Bureau Report 8, 262-264.
IRELAN, W., Jr. (1890) Tenth Annual Report of the State Mineralogist. California State Mining Bureau Report 10, 214-215.
KNOPF, A. (1914) Mineral resources of the Inyo and White Mountains, California; in U.S. Geological Survey Bulletin 540.
NORMAN, L. A., Jr., and STEWART, R. M. (1951) Mines and Mineral Resources of Inyo County. California Journal of Mines and Geology, 47, 48-49.
STONE, P., DUNNE, C., MOORE, J. G., and SMITH, G. I. (2000) Geologic Map of the Lone Pine 15-minute Quadrangle, Inyo County. California Geologic Investigation Series Map 1-2617.
TUCKER, W. B., and SAMPSON, R. J. (1938) Mineral resources of Inyo County. California Journal of Mines and Geology, 34, 386-388.
Paul M. Adams
126 S. Helberta Ave. #2
Redondo Beach, California 90277
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|Author:||Adams, Paul M.|
|Publication:||The Mineralogical Record|
|Date:||Mar 1, 2010|
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