Preaching the Kingdom of God requires the owning and operating of a shale mine. I thought everyone knew that.
Shale is used in concrete so I assume the WT is saving money(or trying too) by mixing their own aggregate. It seems hard to beleive that they can compete with modernized companies(like lehigh)on price when it comes to redi-mixed concrete. I bet they dont operate the pit anymore. Perhaps a member donated it or willed it to them. Or perhaps they use it for gravel.