Economists and historians have identified the period between 1870 and 1914 as one marked by the movement of capital and labor across the globe at unprecedented speed. The accompanying spread of the gold standard and industrial techniques contained volatile and ambiguous implications for workers everywhere. Industrial engineers made new machinery and industrial techniques the measure of human effort. The plight of workers in South Africa's deep-level gold mines in the era following the Anglo-Boer War of 1899–1902 provides a powerful example of just how lethal the new benchmarks of human effort could be. When by 1904 close to 50,000 Africans refused to return to the mines, mining policy began to coalesce around solving the “labor shortage” problem and dramatically reducing working costs. Engineers, especially American engineers, rapidly gained the confidence of the companies that had made large investments in the deep-level mines of the Far East Rand by bringing more than 60,000 indentured Chinese workers to the mines to make up for the postwar shortfall in unskilled labor in late 1904. But the dangerous working conditions that drove African workers away from many of the deep-level mines persisted. Three years later, in 1907, their persistence provoked a bitter strike by white drill-men.