Some states require the use of an engineer during the design process if the retaining wall exceeds a specific number of vertical feet. The overall height includes the portion that is buried in the dirt, known as the key, which is vital to ensure the lower portion of the wall doesn't collapse and cause soil sliding.
Magnesium is almost always found in compound form in nature, with the most abundant source being ocean water. Normally, magnesium is found as magnesite, which is magnesium carbonate, or dolomite. In seawater, magnesium is the third most abundant mineral behind both sodium and chloride. Continue Reading.
Most magnesium comes from seawater which is composed of 0.13 percent of the element in the form of magnesium chloride. It can also be found in natural minerals such as dolomite and magnesite in the form of magnesium oxide.Magnesium can be produced through several different methods such as the electrolytic method, the thermal-reduction method or the most commonly used Pidgeon method.n this process, magnesium is collected from a condenser on the outside of a furnace. High priority magnesium can be attained from the condenser since vapor pressure of impurities that may be in the magnesium are low under the conditions of the tank. The largest producers of magnesium are China, Russia and Canada.