A cubic foot of coal pieces weighs between 40 and 60 pounds. A solid cubic foot of coal can weight up to 84 pouinds. A coal hopper rail car contains 100 tons of coal. I hate you gety a book from quezboy.
As long as your walkway isn't cracked all the way through, you can coat the slab with a concrete resurfacer, a no-shrink blend of Portland cement, sand, and polymer additives that fills divots and makes a uniform finish. Its natural color is dark gray, so buy enough to cover your entire walk. One 40-pound bag coats about 35 square feet. If you want a different color, just add a concrete tint. Before resurfacing, strip off any paint or sealers and watch the weather. Temperatures should remain above 50 degrees F for 8 hours after the pour and above freezing for 24 hours after that.
The stain may not reveal its true color until it has been allowed to remain on the concrete for several hours or longer. Although acid stains are available in limited color selections, you can mix two or more stain colors before application to achieve a different shade or apply one color over another. You can also produce deeper color effects with a stain by making two applications. Water-based stains can also be mixed to achieve custom hues and often are used in conjunction with acid stains to add highlights or expand the color palette. But be sure to check with the manufacturer for compatibility.