In 1876, Anton left his role as deputy to Rossiter. That January, he became manager at the Saints John smelter near
Montezuma, Colorado, where he constructed works with the help of Franz Fohr, Henry Vezin, and Frank Cazin. In September of that year, Gustav Billing approached Anton about joining him at the Germania Smelting, a lead-silver ore smelter south of
Salt Lake City, in what is now
Murray, Utah. Eilers was familiar with Billing's plant, having stopped there on several occasions during his time as deputy commissioner. To sweeten his offer, Billing offered to make Anton a partner. Eilers accepted and immediately went to Salt Lake with Billing. By early November 1876, Anton had the lead-silver smelter working day and night, an amazing feat at the time. Anton was joined at the Germania by Otto Hahn and August Raht, both of whom had distinguished smelting careers. Together, these three refined Anton's concept of slag-types, a way of mixing ores depending on their mineral and chemical makeup to generate predictable products, including lead-silver
bullion, matte,
speiss,
slag, and flue dust. The use of slag-types allowed the Germania to produce bullion on a constant basis, no matter what lead-silver ore the facility received. For his insights at the Germania, Anton was considered the father of lead-silver smelting in the United States. Eilers' partnership with Billing proved professionally and financially successful between 1876 and 1878. About this time, news arrived that Colorado's
Leadville area was rich in lead-silver ore. Seeing opportunity, Billing and Eilers turned over the Germania to Gustav's brother F.W. Billing and left for Leadville, where Anton built a state-of-the-art smelter. The Billing & Eilers smelter became a top tier producer in a short time. Between 1879 and 1881 the works made the pair very wealthy. However, the high mountain location, cold winters, and some health problems led the pair to a friendly split. Anton sold out to Gustav, then headed to
Germany, his first return to his mother country, with his oldest daughter Else for six months. Anton returned to the United States in the summer of 1882. That fall, he was asked to consult on a mine in
Monarch, Colorado, called the Madonna mine. Anton told the mine's owners that the low-grade ore was perfect for smelting with nearby ores. He suggested a partnership, where the mine owners would put up the mine, while he raised money to build a smelter on the plains of Colorado. Anton secured the funds and the Colorado Smelting Company was formed. In July 1883, Eilers completed a smelting facility in
Pueblo, Colorado. Over the next few years, the Eilers smelter as it was called smelted more than $4 million in lead and silver from the Madonna mine. In the process, the smelter also produced a number of internationally renowned metallurgists under Anton's tutelage, including Anton's own son Karl Eilers. Four years later, sensing another opportunity, Anton led the formation of the Montana Smelting Company in
Great Falls, Montana. However, unlike his previous smelters, this one didn't enjoy the success the others did. This was mainly caused by a lack of cheap lead-silver ore. By the late 1880s and into he 1890, the quantity of high grade ore was declining. Other issues, such as the demonetization of silver, impacted lead-silver smelter revenues as well. To counter these industry problems, Anton and other smeltermen attempted to combine forces. Throughout the 1890s, the lead-silver smelting industry continued to struggle. There were too many smelters and too few lead-silver ore reserves nationally. Eventually, the independent minded smelting owners were forced to merge, creating in 1899 a large entity called the American Smelting & Refining Company (today known as
ASARCO). At its formation, American Smelting owned 2/3 of the smelting trusts in the nation, making them a critical player in the ore and mining industry. In 1901, the Guggenheims smelting and refining assets were added to American Smelting. At that time, the Guggenheims obtained a majority of American Smelting shares and began their dominance of the company. Anton played an active role on the Executive Committee and Board of Directors of American Smelting and on its sister company, American Smelting Securities Company, between 1901 and 1910. During this period, he was also on the Board of Directors of
Wells Fargo, a director on the Seneca Mining Co, a director of the United
Missouri River Power Co, and more. In 1910, he retired from the company so he could focus on technical issues he hoped to solve, such as reducing the pollution caused by smelting. Following an illness, Anton died at Sea Cliff, Long Island, April 22, 1917. ==Personal life==