Els River Mill Revisited
Els River Mill (Revisited) The cache is placed as a follow up to the original cache at this fine location, Royfamily's GCK7MW Historical Series - Water Mill placed on 9/8/2004 and archived on 28/2/2009 with 61 finds (the 4th find of my geocaching career), and its successor, MnCo's GC1RH4Z Elsies river mill which was placed on 18/5/2009 and archived on 2/12/16 after 81 finds.
The cache, a small cylindrical camo-pot, is hidden on the site of ruins of the old water mill which is opposite an extensive grassy and party shaded area - an ideal spot for a picnic. Please take care to look out for muggles who may be watching - and to replace the cache securely in its hidey hole - thanks!
To reach the cache, enter through the gates @ S34 09.171 E018 24.378 (open from 07h00-16h00 daily) and after a short distance head left down the dirt road to park @ S34 09.097 E018 24.452 from where it is a short walk across the grass - and the stream - to the ruins.
If the gates are closed or you want to avoid being locked in, park @ S34 09.183 E18 24.730 and head down the trail @ S34 09.178 E18 24.721, marked by a large wooden frame. Follow this path along the fence line for about 150m to where the fence ends then head straight across the fields to the cache site.
You will need to negotiate crossing the small stream (ie. without getting your feet wet!) - depending on the level of water, there are several potential crossing points . . . I crossed over the top of the waterfall and returned via stepping stones a little upstream.
The following is adapted from/based on the description of the original cache at this location, MnCo's Elsie's River Mill, since this was the best available. Many thanks to Mark for permission to use the material he obtained through research carried out at Simon's Town Museum.
Before 1801 the government had a monopoly on milling. But after this was removed, many small mills started to spring up. In 1820 Johannes Brand recognised the economic potential of having a mill here for himself and local farmers, as the nearest one then was over the mountain towards Cape Town.
It is situated on what was then Welcome Cottage Farm and probably operated from 1820 to the 1850s. Farmers enjoyed gathering there - which may be how the farm got its name. But by the 1860's farmers switched to growing vegetables and raising cattle and the mill fell into disrepair.
It was an overshot mill with a 4m diameter water wheel (see here for details). From the mid-18th century this type of mill was known to be the most
efficient available source of power. Water collected in a small mill pond upstream and was channelled down a millrace to the wooden launder over the centre of the wheel, which probably had a hatch to regulate the water flow.
The water wheel was a clasp-arm type, which had apparently replaced the compass-arm type by 1820. See here for a short video of an overshot mill wheel in motion.
All that is left of the pond which is now silted up are a few dressed stones, boulders and a short dam wall. Parts of the millrace, which may have been wood-lined or simply plastered, can still be seen but most has now collapsed.
The mill walls were made from boulders and dressed stone with a clay and cobble filling and lined inside and out with a fine lime/shell plaster. Floors were made of clinker, a hand-fired brick used then for floor tiles and ovens. The wheel was probably wooden, as cast and wrought iron wheels 
were not general used till the 19th century.
The height of the remaining walls shows that the mill had two stories - a ground floor main room with milling machinery, an upper level, and an annex (probably added later) which may have been the miller's quarters, extra storage space or somewhere for clients to hang around whilst waiting for their flour. Given the annex's apparently low roof and thin walls, storage seems to be the its most likely use. Historical records mention a nearby bakery, but no physical evidence of it remains.
See here for fascinating detail on the mill history, how the milling machinery worked, site investigations and computer modelling.