The process of extracting olive oil during ancient times was a very different and labour intensive process.  The type of equipment used to extract oil was an old stone mill, a series of mats and a donkey.

Here is a video of the traditional method of pressing:

• Involves spreading the harvested olives and carting them in sacks in the heat.  The Olives are already partially shriveled which means they have lost moisture and will be subjected to stress.  Not the most ideal conditions for obtaining a premium product. Shoveling the olives into the stone mill and using a donkey to turn the mill.  This was the traditional way of crushing.  Very labour intensive and as you can see the olives are exposed to the elements during the crushing phase.  A few hours more of the donkey going around and around in circles (I wonder if donkeys get dizzy?).  The olive paste (also known as cake) is bucketed and layered onto the mats which are then stacked into the pressed layer upon layer until the press is at capacity.  The press then squeezes the layers together and oozes the liquid (water and oil) to the tray at the bottom.  The oil will be later skimmed off with a jug and poured into a bucket.  As you can see this process is very labour intensive:

Today, a modern olive oil processing plant uses very different technology, is more efficient and is made primarily of stainless steel.

Here is a video of some of the Centrifugal style olive oil processing plant

A modern Olive Producer will invest more than $350,000 for a 1 tonne per hour processing machine.