Arlin Fletcher reminds us that one of the most overlooked aspects of mixing drilling fluid and grouting products is the pre-treatment of the mix water.
One of the most overlooked aspects of mixing drilling fluid and grouting products is the pre-treatment of the mix water. Because water makes up 80-97 percent of the slurry, it should always be a priority to make sure you have good water before you start mixing. Few contractors take the time or effort to pre-treat the water to make sure they are getting full utilization of the drilling fluid or grout. I often hear contractors comparing various manufacturers' bentonite products and discussing how one product just did not mix as well as another. Chances are that the difference is in the make-up water.
The ideal pH for mixing bentonite is between 8.5 and 9.5. Most municipal water has a pH of 7, which is neutral. One of the most common mistakes I find in the field is that people believe the water they get out of a water hydrant is good for mixing, so they very seldom check the pH. If they did, they would find that the pH is usually around 7 and should be treated before they try to mix up their drilling fluid. If mix water is taken from streams, ponds or other sources of surface water, the pH can be below 6.5, indicating hardness.