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Rossi Mine - Barite, Elko County, Nevada 1930s - Present Elko County, Nevada Ivanhoe Mining District T37N R49E In the western pan-handle of Elko County, there is the Rossi Mine. It is an intentionally quiet, professional barite mining operation, lost in the hustle and bustle of the large gold mines surrounding it. But, in truth, it has been there, producing ore, off and on, long before the current gold rush. It was discovered by a cowboy, Antonio Rossi and Carlo Cereghino of Battle Mountain in April 1937. Barite production began in 1947. It is still in operation. It has produced millions and millions of tons of barite. It still has millions of tons of barite reserves, albeit at a lower grade and higher stripping ratio. How do I know this, I was in the mine engineering department there from 1977 - 1985. During this period the mine was owned by NL Industries, Baroid Division. When consolidation came to the barite industry in the middle - late 1980's, NL Baroid was purchased by Dresser Industries, who in-turn were taken over by Haliburton, the biggest petroleum service company in America. In late 1984, we had also located some shallow gold shows on the Rossi claim block in the upper-plate Vinini Formation. It was suspected that the lower plate rocks would contain Carlin-type gold mineralization. But because of its depth, the poor petroleum services economy and a general lack of technical experience in deep, highly technical, underground mining and exploration it was decided to joint venture this part of the operation. Mr. Ken Snyder, an astute, clever, nice guy, competent NL geologist, for whom the Ken Snyder Mine, near Midas, in now named, found several surface gold shows on the property. He believed you would find significant gold deposits in the underlying lower plate rocks. That was 1985, when the barite operations cut back to the point that I left the operation and went to work at Freeport's Bell Mine (now the Independence Mine). It is interesting to see these thoughts, becoming a reality with the Barrick and Meridain Joint Venture Rossi underground gold venture. But this page is about barite ... and the quiet, mining operation that produces ore for oil. The barite at the Rossi Mine is of the gray, sedimentary, bedded, variety instead of the white, hydrothermal, vein-type. At the Rossi Mine there are two major barite ore bodies that have been mined through time. The high-grade orebody - the Sage Hen and the low-grade orebody - the Queen Lode. There are also a number of smaller satellite deposits, that currently can't be produced as cheaply as the two major ore bodies. What is the difference between low and high grade barite? Purity, of course. Pure barite has a specific gravity of 4.50 (4.5 times heavier than water). The break point is 4.20, if the specific gravity is 4.20 or greater, it is high grade. Below 4.20, it's low grade. Barite is primarily used for its property of being heavy. It is used primarily in oil and gas well drilling to control hole pressure. You mix the ground barite with water to make a grayish looking 'mud', then pump the mixture down the hole to control the gas pressures found in the well. Other minerals are heavy, too - like iron, lead or witherite (barium carbonate). But barite has the additional properties of being a cheaper commodity, relatively inert (doesn't react with many chemicals), insoluble, nontoxic (you can even eat it and it has medicinal uses), soft (low hardness of 3-4 so it doesn't wear drilling equipment or pipe) and if you're the driller it won't leave you with red or reddish-pink clothes and skin discoloration like hematite (iron oxides). This adds a new dimension to the word 'redneck', but the pinkish color - well it just ain't smooth to go in a west-Texas bar after work to get a cool-one dressed in pink. Barite just gives you a manly, dirty look and easily washes off. The primary impurity in the Rossi barite is silica (quartz). Just because the specific gravity is below 4.20, doesn't mean the jig-is-up. Low grade material can be blended with very high grade barite to make a blend of 4.20 (an art - but really cheap to do). The low grade can also be beneficiated (processed) to clean out some of the impurities. The basic concept is: if the impurities are in the +1/4 inch size, like little seams of non-barite rock or removing some of the country rock that was included with the barite when mining - jigs are the cheapest way to get rid of most of the waste. Other common ways to beneficiate the lower grade barite ore is by using tables or flotation plants. These processes significantly raise the cost of the final product. Because Chinese ore has been produced so inexpensively since the early '80's. These methods are not so commonly used now. Overseas, where labor costs are minimal, the common beneficiation techniques are handpicking and washing. People sit in the barite mines and hand sort ore. Sounds complicated, but these people are poor, not dumb. Once you work in a barite orebody for a few days, you can get the feel and look of high grade ore. It goes in one pile while the other goes over the bank. If the stockpiled ore is of marginal grade, you can run the hand selected ore on a conveyor belt and wash it with water. This gets rid of any dirt and clay impurities. It can raise the grade a few points. Which might mean the difference between a sellable product and a pile of rocks.
SE1/4 Section 15 and NW 1/4 Section 22, T37N R49E Average Elevation: 5,850 feet This orebody is high-grade. The average specific gravity has been consistent at 4.28 (common knowledge as every competitor has made a weekend trip to the Rossi to collect some personal samples for their collection - right). It is about a mile long in strike and dips to the northwest at about 45°. The barite horizon, consisting of one to three beds, ranges in thickness from a few feet to over one-hundred feet (obviously the thicker areas are now pits). The ore is massive, homogenous and gray in color. Once in a blue moon, in a fault zone, you can find some crystalline barite. This is extremely rare. The country rock is the Ordovician Vinini Formation, primarily chert and argillite.
W 1/2 Section 27 T37N R49E Elevation 6,100 feet. 1 mile south of Sage Hen Orebody This orebody is low-grade. The average specific gravity is less consistent. It ranges from 3.56 - to better than 4.20. The grade of a typical weekend grab sample ranges from 3.86 - 4.10. The orebody is a first-year-structural-geology-teacher's dream. It is well exposed near the top of a barren hill. It forms a tightly folded plunging anticline-syncline structure faulted on the west, eroded to the south. It plunges northerly down the hill under a red volcanic tuff unit. There it becomes the unmined Queen Lode Extension orebody. An orebody, with similar characteristics as the Queen Lode, just with more overburden. The barite is beautiful, thinly bedded with argillite and chert. Geologically speaking it is very interesting. It is about one half mile long along the axis and plunges to the north from about 20 - 45°. The barite horizon, contains many, many thin beds, the total horizon ranges in thickness to well over one-hundred feet. The ore is bedded, and is gray to grayish-brown in color. There are no barite crystals here, but it contains many tubular fossils or psuedo-fossils, or worm tubes. In 1985, the debate as to what they were was still afoot. One day I'll check the literature to see if a conclusion has been drawn. The country rock is the Ordovician Vinini Formation, primarily argillite and chert.
USGS Topographic Map of Rossi Mine (elevation in meters)
USGS Aerial Photograph of Sage Hen Orebody, Rossi Mine In the non-mined area between the pits, the orebody is high-grade but thinner making a higher stripping ratio.
USGS Aerial Photograph of Queen Lode Orebody, Rossi Mine The drill roads immediately north of the Queen Lode pit is the location of the Queen Lode Extension. Most of the outlying drill roads were created for gold exploration.
Why is 4.20 the magic specific gravity number? Most of the barite is used for the oil industry. They are the ones that buy it. The major producers are called 'oil services companies'. The oil companies set the requirement of 4.20 as the minimal acceptable standard for ground barite used for drilling products. So, you either produce a 4.20 product or ... you don't sell it to them. Strong incentive. On the other side of the proverbial coin, if you have a pile of 4.30 specific gravity ore - you're in hog heaven. Why? There are no 'at-a-boys' given for shipping a bag of 4.28 specific gravity barite to the oil rig. So, you blend the lower grade ore with the high-grade ore and make it a 4.20 specific gravity product - then you advertise 'consistency is a virtue'.
Jigs work like this: You crush the rock to, depending on the waste size (determined by metallurgical testing), to 3/4 to 1/4 inch in diameter. You put the crushed rock in a hopper and feed it to the jigs. The jig is a brilliantly simple machine. A jig is a slanted rectangular box. By design, you generally have two jigs side-by-each (two parallel rectangular boxes). The jig feed is combined with water and fed to the jigs. There the jig shakes and pulsates the rock in water. The heavy barite goes to the bottom, the lighter waste rock (at the Rossi Mine, chert and argillite) is displaced to the top. The barite is collected in cups that empty into little cutes on the sides of the jigs. It is stockpiled and taken to the mill, where it is either used to blend up low-grade ore or sent directly to the mill where it is ground into a white powder. The waste rock passes over the end of the jig where it stockpiled. Stockpiled? Yes, this crushed rock makes great road base material. Jigs can be fine-tuned, if watched carefully, to roughly separate the lower grade barite from the higher grade barite. At some mines, the barite, itself, in some sections of the bed is higher grade and in other areas lower grade. The jig process works but a lot of good barite goes over into the waste product (tails).
Where does the mined ore go from here?
The ore is trucked 35 miles south of the mine to the rail siding of Dunphy, in Eureka county. There it is crushed, and either shipped in crushed form or milled into a powder. Most of the crushed barite is shipped by rail to the Gulf coast, where it is ground and sold to the oil-patch. The ground barite is either shipped in bulk or bagged (100 pound bags) by rail or truck. The market is primarily the western and northwestern states.
~~~~~~~~~~~~~~~~~~~ CAUTION: MINES ARE DANGEROUS PLACES!! Don't get too near the edge - you can fall or slip in. Don't got too near the edge - the wall can slough off with you on it Don't go down in an abandoned pit - rocks can fall on yer head. Wear a hard hat around active or inactive mines. Not all explosives go off - don't go playing with wires sticking out of the dirt.
If the mine is active - the equipment is big - it can squash you or your pickup like a bug. Horns can mean blasting - get out NOW and WHAT WERE YOU DOING THERE IN THE FIRST PLACE WITHOUT PERMISSION. Always check in at an active mine - don't initiate your own guided tour.
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~~~~~~~~~~~~~~~~~~~ I can't locate my photos of the Queen Lode, so as I make it back that way I'll stop and snap a few.
Remembrances
Here is a brief list of some people and thoughts I recall about them, who worked at the Rossi Mine during the period when I was there. As life awards some precious extra blocks of free-time, I will flesh it out.
E-Mails (Please Send Yours and We'll Add It)
Addendum
I feel that there is at least one and probably two large concealed barite orebodies left to be discovered at this property. The faulted eastern end of the Sage Hen and the faulted western side of the Queen Lode. Maybe, the gold exploration people will run on to them.
Additional Information: Northeastern Nevada Museum
Recent Photos by Dan Turner
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