While his wife and children stayed in England and France, Burnham returned to North America in 1907 and for the next few years became associated with the Yaqui River irrigation project in Mexico with his brother Fred. In 1908, he and W. A. Wadham of London, England, took a month-long geology and mining trip through Sonora on behalf of American and English business partners. Negotiations were made for the purchase of four properties: the Batue, Mequite, La Fiera, and another property. He considered the La Fiera to be the best of the lot and a small force of men under the supervision of John Anderson was put to work there. In 1909, he traveled with Hector Walker of England on a 300-mile journey from Phoenix, Arizona into Mexico, and then east through Chihuahua and into the Sierra Madres to look for good grazing lands and minerals. His brother purchased water rights and some of land in this region and contacted an old friend of the Burnhams from Africa, John Hays Hammond, who conducted his own studies and then purchased an additional of this land—an area the size of Rhode Island. Just as the irrigation and mining projects were nearing completion in 1912, a long series of Mexican revolutions began. The final blow to Burnham-Hammond plans came in 1917 when Mexico passed laws prohibiting the sale of land to foreigners. The Burnham and the Hammond families carried their properties until 1930 and then sold them to the Mexican government.