Drilling slurry dewatering: water-cooled drilling in stone and concrete
Drilling slurry dewatering for water-cooled drilling in stone and concrete: sizing, working load and fluid limits explained. Read the guide!
Key points at a glance
Drilling into stone or concrete with water cooling produces a mixture of water and fine mineral cuttings. In a quarry that is the flushing water from blast hole…
The term drilling mud is used for two very different things, and the difference decides whether a filter bag is any use to you.
The mixture is collected, usually in a tank, a sump or a bowser, and then fed into the bag from above by pump or hose. The bag is…
Which drilling slurries this page covers
Drilling into stone or concrete with water cooling produces a mixture of water and fine mineral cuttings. In a quarry that is the flushing water from blast hole and core drilling. On a construction site it is what comes back out of a diamond core drill. In both cases the material is mineral, water based and heavy, and it is exactly what a filter bag handles well.
Confirmed applications are water-cooled drilling in quarries and drilling and cutting work in concrete. Those two are where the method is established and where we can size a bag from experience rather than from assumption.
Drilling mud dewatering: what this page does not cover
The term drilling mud is used for two very different things, and the difference decides whether a filter bag is any use to you.
If your drilling fluid is a mineral suspension in water, with cuttings from rock or concrete and no engineered additives, this page applies. If it is an engineered drilling fluid, with bentonite, barite, polymers, weighting agents or an oil-based or synthetic base, this page does not. Bentonite in particular is designed to stay in suspension and to seal a borehole wall, which is close to the opposite of what you want a filter medium to encounter. It blinds a textile quickly and gives up water reluctantly.
That does not automatically mean no. It means we check the specific fluid before you order, rather than after. Tell us the base fluid, the additives, the solids content and the quantity per batch.
How drilling slurry dewatering runs on site
The mixture is collected, usually in a tank, a sump or a bowser, and then fed into the bag from above by pump or hose. The bag is open at the top and needs no coupling, which is why it works with the pump you already have on the rig.
Mineral cuttings settle and drain comparatively well. Water leaves across the wetted textile area, the coarse fraction drops out quickly and the fines build a cake that takes over part of the retention as the cycle runs. Once the flow has fallen far enough, the bag is lifted by its loops and goes for disposal with its contents.
Two site conditions decide whether this is smooth or awkward. The bag needs level, load-bearing ground with somewhere for the filtrate to go, and the position has to be reachable by whatever will lift it out. On a quarry floor or a site compound both are usually straightforward, which is a large part of why the method suits this application.
Heavy material, so the working load decides the size
Rock cuttings are dense. A drilling mud dewatering bag will reach its rated load long before it looks full, and that is the single most common sizing mistake in this application.
| Situation | Sensible starting point |
|---|---|
| Occasional core drilling, small batches | Size M, 0.125 m³ |
| Regular drilling work, one bag per shift | Size L, 0.5 m³ with 900 kg |
| Higher volumes, headroom or hook height limited | Size XL, 0.8 m³ with 900 kg |
| Quarry operations, floor space tight | Size XXL, 1.25 m³ with 900 kg |
Take the 900 kg rating on L, XL and XXL and mark a fill height. With material at 1.5 t/m³ after draining, an XXL reaches 900 kg at well under half its geometric volume. Two L bags will often move the same tonnage with less risk at the lift. The guide sets the calculation out in full.
Filtrate and what leaves the site
The water that comes out has been filtered, not treated. With clean mineral cuttings there is usually little in it beyond suspended fines and whatever alkalinity the rock or concrete contributes. That is not the same as saying it can be discharged. Where it goes depends on the material, on the site and on your consent.
The point of dewatering is what it does to the load leaving the site: the same solids go out as a drained mass rather than as a tanker of water. How the dewatered material is classified and where it goes is a matter for you and your waste contractor. We supply the filter medium and the sizing, not the disposal.
Questions from quarry and drilling contractors
Will a filter bag handle bentonite drilling fluid?
Not as a general rule. Bentonite is engineered to hold particles in suspension and to seal, and it blinds a filter textile quickly. Where bentonite is present we look at the specific case rather than giving a blanket answer.
Can I pump straight into the bag?
Yes. The bags are open at the top and take a hose or pipe from above. There is no fixed inlet connection, so no adapter is needed. Watch the fill rate with very thin slurry: filling in stages and letting water leave in between uses the filter area better.
How many bags will a shift use?
That depends on the drilling method, the water rate and the cuttings volume. One bag with a real batch, weighed at the end, gives you a figure you can plan a season around.
Does the bag survive sharp cuttings?
The 200 g/m² geotextile at 2.0 millimetres is robust and handles rock flour and drilling fines routinely. It is not cut resistant. Where broken tooling or coarse sharp material can reach it, put a screen in front.
Is a drilling sludge filter bag reusable?
No. These are single-use products. After dewatering, bag and contents are disposed of together according to how the material is classified.
We drill in several materials. Does one size cover it?
Often not, and that is worth knowing before you standardise. Density varies a great deal between rock types, and the load rating follows the density. If you send us the materials and the quantities per batch, we will tell you whether one size covers the range or two make more sense.
Still unsure which filter or next step fits?
Send us the medium, dimensions and application. We will help you decide whether a standard product is suitable or whether the case needs a custom solution.
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