Eldorado Valley

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Directions: From the Stratosphere Casino head northeast on Las Vegas Blvd about 3 miles and bear right to merge onto US-515/93/95 south towards Boulder City. Follow US-93/95 for 17 miles and then merge onto US-95 South (Veterans Memorial Hwy) towards Searchlight. About 6 miles north of Searchlight, cross the highway and head back north until you reach an unmarked dirt road that heads due east toward the Ireteba Peaks.

(Fig. 03) 01/26/15 Trip Notes: Harvey Smith, Robert Croke and I decided to do some four-wheeling around the Eldorado Valley area, north of Searchlight, NV (Fig. 02). Even though the weather was overcast and a little threatening at times, it turned out to be a relatively nice day. Our journey started out in the valley between the Highland Range and the Irebeta Peaks (refer to Fig. 02). We headed due east until we reached the powerline road (Fig. 05) which took us to a wash that cut through the mountain range. Leaving the powerline road (Fig. 06), we were now again heading east towards Lake Mohave. This wash led us towards Copper Mountain and Solicitor Mine Road (Fig. 07). At the end of Solicitor Mine Road we intersected with Rockefeller Mine Road and turned left, heading northeast. This whole area is filled with hundreds, if not thousands, of Teddy Bear Cholla cacti (Fig. 10). We followed this until it intersected with Copper Mountain Cove Road, where upon we took a right and headed east towards Lake Mojave (refer to Fig. 02). Once we reached Lake Mojave (Fig. 08 & 09) we decided to take a lunch break. I was surprised to find out from Bob’s GPS readout (Fig. 03) that we ended up traveling a total of 46 miles for the day, and dropped nearly 3,600 feet in elevation upon reaching the lake. (scroll down for more below)

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(Fig. 10) Trip Notes (con’t): From the lake we began our return by driving back up Mountain Cove Road (Fig. 11) to Rockefeller Mine Road. Just before reaching Rockefeller Mine Road we were afforded a nice view of Copper Mountain (left), Ireteba Peaks (center) and Opal Mountain (right) in (Fig. 01). When we reached the end of Rockefeller Mine Road, we followed the power line road west as it paralleled Cottonwood Valley Road. Imagine our surprise when we came upon the rusted out steel hull of a boat (Fig. 12). A few miles shy of Searchlight we crossed Cottonwood Cove Road for the second time and headed north on an unmarked road that led us to the Oakland Mine site (Figs.13 thru 24). Considering the overall size of this site, the number of shafts and adits, its still standing mine structures, and signs of recent activity, it is amazing how little there is about it on the Internet. I couldn’t even find any indication of what ores were mined here. Though I couldn’t find a date, the steam driven piston and belt system in (Fig. 16) was made by the Ingersoll Rand company of New York. It appears that it was used to drive the minehead in (Fig. 17). The shaft here was quite deep (Fig. 18). A little further up the hill was a fairly well preserved 4-stamp battery (Fig. 19). A stamp battery was a mechanical crusher, noisy, heavy and somewhat awkward to operate. Its traditional use has been for the processing of mineral extraction, whether it is copper, silver, gold, or any other metal contained within host rock.  The stamps were heavy metal weights that were lifted and dropped on the ore by a crankshaft. The crushed ore would then be further refined, usually by a mercury or cyanide process. Unlike placer deposits that produced gold nuggets already separated from rock, lode gold deposits were of little value if the gold could not be efficiently removed from the host rock. With the gold released from its host, the amalgamation process with mercury could be done, allowing for the final extraction of the gold. Refer to the section, ‘Stamp Mill Operation’ below. Notice the wooden ladder at the bottom of the shaft in (Fig. 22). Located behind all of this was a hillside full of lumber (Fig. 23); what appears to be the remains of several old buildings that probably housed the miner that worked the site. Notice how they used some old cars to shore up the embankment on the side of the road in (Fig. 24).

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Stamp Mill Operation. First, a miner would bring the ore to the mill and load it into the ore car. The heavy ore car was then brought up to the mill on a track by the aid of a winch. Once the ore was at the top of the mill, the car would be emptied on to a screen called a 'grizzly', a metal grate with separators about 2 inches apart.  Smaller material would fall through the screen and into the ore chute while larger material would slide across the 'grizzly' into the crusher. The larger pieces of ore passing into the crusher would remain until they were pounded into a workable size (less than 2 inches) then fall into the ore chute.
 
The ore, now about the size of a course gravel would, slide on to the heavy metal plates under the stamp battery where water would be poured on. The battery usually consisted of sets of 5 stamps (5 stamp, 10 stamp, 20 stamp mills, etc). The stamps would be lifted in sequence by a powered cam and then dropped using gravity to to pulverize the ore into a fine, sandy slurry.

The slurry would be spread evenly over the recovery table. The recovery table was a copper-sheeted table that was coated with mercury previous to the processing run. The gold in the sand would adhere to the mercury while the sand would pass over to the next step in the process, the concentration table. The concentration table was a table with runners which would shake or vibrate, slowing the heavier material containing the gold to a stop while letting the worthless tailings pass to a conveyor to be transported away. The crushed sand from the table would be loaded back into the stamp mill, pulverized further and once again slurried across the mercury coated recovery table.

Once the mercury on the recovery table was full, or the ore run was complete, the gold and mercury would be scrapped off the table and separated. Separation would be accomplished by straining the amalgam mixture through a chamois. Further separation could be done by a retort process. The retort would heat the mercury removing it from the gold as vapor and condensing it for later use. The remaining gold was now in amalgam form, ready for further refinement processes such as smelting into bullion.