<span>In the years before the Civil War, the economic interests of Americans in the North and Northwest grew increasingly further from those of Americans in the South and Southwest. Although the Civil War itself was caused by a number of different factors, the divergent paths taken in the economic development of North and South contributed to the animosity between the regions, the development of the Confederacy and, ultimately, the victory of the Union.</span>
Well based on the fact that the very first patented rock crushing machine was made in the year 1830, and the first successful, Eli Whitney Blake's, was in 1858, I'd say the development process was around 30 years.
