38.287710° -118.361510°

An overview:

The Endowment Mine was the first mine in the district to be worked. The mine produced silver-lead ore in the late 1800's. The Endowment Mine has been developed by several thousand feet of workings including three winzes and numerous stopes and raises on five different levels. According to McGill (1973) the Endowment Mine produced approximately $1.5 million in ore from the late 1800's to the early 1900's.
-Exploration of the Marrietta Mine Region, 2010


The Endowment Mine was primarily operated as a silver - lead mine until 1904. Lessee's then worked the mine, as recently as the 1940's. A 1922 report claimed:

Endowment Mining Co. These deposits are so small though that they are only interesting to a small group of men working independently, producing shipping grade by sorting very closely. The property is not worthy of further consideration.
Endowment Mine Report, June 1922, A. F. Carper

William Vanderburg described the property in 1939:

The Endowment mine is 3 miles northerly from the old camp of Marietta. This property comprises five unpatented claims owned by B. F. Baker and A. V. Reeves of Mina, Nev. Property was idle from 1884 until 1923, when it was worked by lessees. In 1926 lessees shipped 144 tons of ore averaging 81.6 ounces in silver, $2.34 in gold, 3.83 percent copper, 5.25 percent lead, and 7.6 percent zinc. Production from this mine, according to statements of men familiar with the property, has been approximately $150,000, although some estimates in earlier reports give a figure as high as $1,500,000 prior to 1884. In recent years the property has been idle. Development consists of a tunnel reported to be 500 feet long, a winze 333 feet deep sunk from the tunnel level, and several other winzes. Two veins occur in quartzite and quartzite conglomerate with inter-bedded argillite. The width of the veins ranges from several inches to 6 feet. The principal values are in silver associated with cerussite, smithsonite and copper carbonates near the surface, while at depth galena, sphalerite, pyrite, and a little chalcopyrite are associated with silver. The following account of the mine taken from an early report by Whitehill is of interest. The vein matter is decomposed and carries carbonate of lead, argentiferous galena, and iron. By mill process the ore yields from $50 to $125 in silver. A tunnel has been run in on the vein a distance of 500 feet and connects with a shaft at a depth of 200 feet. From this tunnel level two winzes have been sunk 200 feet, a distance of 300 feet apart. The pay ore is about 5 feet in width, though the vein matter is much wider. The 5-stamp quartz-mill, erected at Philadelphia by the State of Nevada for the Centennial Exhibition, was removed to this district and has run very successfully on the ores obtained here. The Endowment is an incorporated company, the stock of which is listed in the San Francisco Stock and Exchange Board. The assessments levied have been $50,000 and the yield of bullion $88,764.
-Mines of Churchill and Mineral Counties, William O. Vanderburg, 1939

They were shipping bullion.

Yesterday evening Wells, Fargo, & Co. received per southern stage three bars bullion, valued at $2,688 [$75,832 in 2022 dollars], from the Endowment mine at Marietta.
-Daily Appeal, August 9, 1877

Sixty men were working here in 1877.

GOSSIP FROM ESMERALDA COUNTY.
On the southern stage of Monday evening arrived a gentleman largely interested in the Endowment mine at Marietta, Esmeralda County, and reports that the prospects of Esmeralda have not been as bright for the past ten years as they are at present. The milling interests are looking up, and all the mines which are being worked now are yielding handsomely for their owners. Marietta now contains a population of 300 souls, and all the men there are profitably employed. The Endowment mine and mill (five stamps) employs sixty men. Their shipments during the last fiscal month amounted to over$16,000.
-Daily Appeal, September 12, 1877

Improvements were being added and making the mine more productive. This was most likely the end of its most productive period.

The Endowment mine is constantly improving both in quality and quantity of pre in the winze that is being sunk from the 200 foot level. The mine has been prospected to the depth, from the surface at the end of the tunnel, of 480 feet. The engine for the new hoisting works arrived yesterday and will be ready to start up by the 25th as everything is in readiness to set it up, and then sinking can be more rapidly done than by the slow work of whims to raise ore and waste. More stamps will be added to the mill in March.
-The Daily Appeal, January 26, 1878

A STRIKE of considerable importance was made last week in the Endowment mine at Marietta. An apparently permanent four-foot deposit of ore was uncovered on the 400 level, and about 300 feet east of the body of ore discovered some time ago. The ore is said to be worth $155 per ton, and stopes have been opened for working facilities ' on the 400 and 500 levels. The discovery is really a valuable one and will, no doubt, add much to the permanency of the mine.—[Esmeralda Herald.
-Yerington Times, June 12, 1878

At this point, things began to slow down.

MARIETTA LETTER
The Endowment mine has a ten stamp mill which is idle at present but expects to start soon.
-Reno Evening Gazette, May 24, 1880

Frank Maguire, who is heavily interested in the Black Mountain district, and resides in Marietta, is spending the week in Tonopah. Mr. Maguire was one of the first locators in that district and has great faith in its future. He located there in 1874 and has mined his properties ever since. The True Blue, Woodchuck, Rip Van Winkle, Golden Arrow and the Olive Branch are the principal holdings of Mr. Maguire. He says he has always stuck to Marietta and has had good reason to do so in view of the fact that the great Endowment mine, which is not far away, has been a wonderful producer, its record to date being an output of nearly $2,000,-000. This mine is now under option to Mr. Jamison, who is well known in Tonopah, for a big figure. He has already made the first payment.
-Tonopah Bonanza, March 17, 1906

While no longer considered a large producer, the Endowment Mine was famous enough in these parts that just being near it was considered a good thing, like this advertisement for mining stock:

MARIETTA
The Camp of Real Mines Developing on High Grade Ores.
Plenty of Low Grades Also That Would Be Called High Grade in Any Other Camp.
I have a display of ore at Radcliff's Jewelry Store that is in itself "Jewelry Ore" representing six mines of Marietta.
Do not fail to see this ore and be convinced that this state has a silver camp with mines operating on high pay ore.
You have put much of your money in sagebrush mines and are now sending thousands out of the state on oils.
Remember there is no better investment than a REAL MINE and that the general public seldom gets a chance on the start of such mines.
I offer you such an investment which you must take advantage of AT ONCE to be in on the big end.
I have spent seven months carefully investigating this district.
When I was SURE I was right I backed my judgment by my cash.
My experience has covered mining camps in Alaska, Mexico. British Columbia, and most of the Western states as an examining engineer for others.
Am now operating for myself and for you if you come with me.
I "Shoot Straight" and put money derived into the ground in actual development work.
Am offering new the pre-organization stock in EAST SILVER GULCH MINING CO. OF MARIETTA at 10c a share until Saturday A. M.. only.
Will make special sacrifices for amounts over $1000.
Will be shipping ore in sixty days and a dividend before Xmas.
Have over 2000 feet on two good veins of high grade Silver and Lead ore with highly mineralized zone 200 feet wide between them.
The Endowment Mine only a quarter of a mile distant produced $1,250,-000 in the old days
And the whole camp has a record of over three millions in the old days.
Production here will doubtless exceed this in the next two years.
Reports and further information see me at Radcliff's during day or Overland Hotel evenings by appointment.
CAPT. L. W. WHITING Practice Civil and Mining Engineer. OFFICE: MINA, NEVADA
-Reno Evening Gazette, March 25, 1920

Here it is, some 40 years later, and interest in the Endowment has returned, despite the 1922 report mentioned above.


Capt. Whiting said that good progress was being made on the Endowment mine, which he is operating. He
expects to cut the main orebody at depth in the next few days. The Endowment was one of the bonanza producers of the early days of the district. .
-Reno Evening Gazette, April 7, 1925

Special to The Journal. - MINA, Aug. 3.—After considerable' delay due to recent cloudbursts the Whiting brothers, who are operating the famous old Endowment mine at Marietta have completed the hauling of a 90-ton car of ore to Belleville for shipment to the new flotation mill at the International smelter, This ore was extracted in development work below the old stopes and will average considerable over $60 a ton for primary sulphide ore, with values in gold, silver, copper, lead and zinc, all of which the smelter pays for. The mine is now equipped with hoist, compressor, sharpener and all necessary tools for extensive work. Present plans are to continue development on the fourth level to tap at depth two large ore shoots in the sulphide zone at considerable depth below the old workings where the old timers extracted over a million dollars from the chlorides.
-Nevada State Journal, August 4, 1925

"There are few better showings in the state than is presented at the old Endowment mine," said L. C. Phoebstel, an experienced miner, "and the leasers there are sure to make a stake. On the three hundred level they have from twelve to eighteen inches of ore running around three hundred dollars a ton and important orebodies in various parts of the property. A carload was recently shipped which averaged better than a hundred dollars a ton, and another car lot is now ready to go out."
-Reno Evening Gazette, April 4, 1926

Enough minerals remained and its fame was so substantial that interest never waned.

WORK PROCEEDS AT ENDOWMENT
The newly discovered vein in Cloudburst ground on the Endowment mine in the Marietta district has been developed down to a depth of forty feet. it was reported yesterday. The Strategic Metals of Nevada. Inc.. which is the operator, will carry on a development program in the shaft and when the weather permits further operation will be undertaken. The ground consists of about twelve claims.
-Reno Evening Gazette, December 14, 1940

Unlike many Nevada mines closed during World War II, the Endowment Mine was granted an exception and remained working.

Old Endowment Mine Reopened
Bradshaw Granted Development Loan
The old Endowment mine in the Marietta district, twenty-six miles southwest of Mina in southern Mineral county, is to be reopened after a long period of neglect by its owner, Mark G. Bradshaw, widely-known mine operator and engineer of Tonopah, to whom an RFC development loan has been granted for the purpose. In a communication to the Gazette from a correspondent at Tonopah, it was stated that the Marietta district has produced lead, zinc and silver in substantial volume, now vital as strategic metals, and Bradshaw's property has shown exceptional promise of becoming a major producer. One of the historic mining districts of the state the Marietta district was first discovered in 1860, coinciding with the opening of the famed camp of Aurora, once the home of Mark Twain. The Endowment mine, owned by Bradshaw, was one of the early producers and is credited with a production of $1,300,000. Prof. Francis Church Lincoln, in a report on the property, said: "The E W veins in the Black mountain section, in which the Endowment mine is located, occur in black monzonite intrusions. They contain base metal minerals including galena, sphalerite and at the surface they are rich in silver." Bradshaw said that he plans to begin extensive work on his property immediately.
-Reno Evening Gazette, May 8, 1943