On 10/08/12 21:37, Richard YOUL wrote:
>
> By the way, how do they fill those sand towers?
>
>
That's what the pipe on the outside up to the top is for. I believe they
blast it up the pipe with compressed air.
Cement is delivered to the hoppers at the concrete works via a similar
system.

The sand these days probably has additives to repel water and make it
flow better.