The Trigo Mountains of southwest Arizona have played a prominent part in the history of the lower Colorado River country. The range trends roughly north-south and consists of extremely rugged and broken country. The Trigos extend from Norton's Landing on the Colorado River north-northeast to Weaver Wash, near the North Trigo Peaks, a distance of about 35 miles. The mountains are cut by many dry washes and arroyos. The eastern portion of the range lies within the Yuma Proving Ground while the western part is home to the Trigo Mountains Wilderness area.
The Trigo Mountains were heavily prospected by Americans during the late 1870's. The southern portion of the range in particular yielded many rich deposits of silver. But throughout the late 1800's, a persistent rumor of a massive silver ledge in the central part of the Trigos circulated among the miners of the lower Colorado River country.
An anonymous Mexican prospector is said to have discovered the fabulous silver lode sometime in the late 1800's. His name may be unknown, but the skill of the Mexican miners in general was legendary. The Mexican "gambusino" or miner had a knack for finding ore bodies. Mexican prospectors were responsible for many of the big strikes in the American Southwest. Jose Maria Mendivil was famous on the frontier for making not only one, but two major strikes! Mendivil discovered the rich Apache lode at Picacho and then followed it up with another find in the Trigo Mountains. Mendivil's second big strike was the Clip Mine which turned out to be the district's biggest silver producer. Another Mexican prospector named Felisario Parra discovered rich gold placers in the Chocolate Mountains of California. These placers became known as the Mesquite Diggings. Most of the prospectors that worked in the La Paz goldfields during the early 1860's were Mexican. Indeed, many of the mining techniques used by Mexican prospectors were adopted by the Americans when they entered the country.
It is fairly certain that the famous prospector Jose Maria Mendivil actually handled some of the ore from the lost ledge. (One account of the story has Mendivil finding the lode.) The Mexican prospector seems to have been a friend of Mendivil's and confided in him. He presented Mendivil with samples of ore and described his discovery, claiming that the silver ledge was "less than a day's walk north of the Clip Mine." The ledge has never been found.
The history of mining in the lower Colorado River country of Arizona extends back to the early Spaniards. The Spaniards and their successors, the Mexicans, scoured the mountains and deserts of Arizona for mineral wealth. They left abundant evidence of their mining activities in the form of old mine shafts, prospect pits, arrastres, and tools in virtually every mountain range in the American Southwest.
The first real gold rush in Arizona didn't occur until the Americans entered the scene. The year was 1858 and the discovery occurred on the Gila River, some 20 miles above its junction with the Colorado River. A prospecting party led by Colonel Jacob Snively found rich deposits of placer gold in the gravels near the river.
The following years witnessed many big strikes in the mountains of southwest Arizona. 1862 was a pivotal year in Arizona mining history. In that year, the rich gold fields of La Paz were discovered by an old mountain man named Paulino Weaver. The placer deposits of La Paz would eventually produce nearly $8 million worth of gold. The massive lead and silver deposits of the Castle Dome Mountains were also discovered in 1862. Nearly 20 million pounds of lead were eventually extracted from these deposits.
The following year, in 1863, silver was discovered in the Trigo Mountains by that inveterate prospector Jacob Snively. Like the lead deposits near Castle Dome Peak, the Trigo silver deposits were left virtually unworked for a number of years. Prospectors were searching for gold instead! Finally, in 1877 the Trigos came to life. In that year, the Black Rock and Pacific mines were located. The following year, the famous Red Cloud Mine was discovered by a prospector named Warren Hammond. The Red Cloud ore body was immense. The mine ended up producing silver longer than any other operation in the district. The massive Red Cloud orebody consists of highly mineralized fault gouge. It is comprised of brecciated andesite and silver-bearing galena.
Placer deposits of gold occur on the west flank of the Trigo Mountains from the Cibola area south to the Paradise Valley section of the Colorado River. Small placers have been worked in the dry washes and arroyos of the Trigo Mountains for many years. At least as early as 1866, miners were recovering gold from the sands and gravels that drape the western flank of the Trigos.
Metal-detecting prospectors can find placer gold in many of the alluvial deposits surrounding the Trigo Mountains. One location that has yielded small nuggets lies in the North Trigo Peaks. The reddish-colored, cemented gravels in and around Weaver Wash have been the most productive.