Challenging quarry conditions require specialist screen washing processes to make the most of extracted construction materials.


Granite is nearly always hard and tough and due to this is used predominantly in the construction industry.

Granite is used as dimension stone and due to the grandeur associated with this stone it is often used in the construction of prestigious buildings. When polished Granite is highly decorative like Marble and a popular use is on Kitchen Worktops.

There is also demand for granite for use in road construction due to its ability to aid vehicles stopping and reduce skidding.

At PowerX we have been processing Granite at Quarries like Shap, Roan Edge and Gilfach for several years. These operations have been a mix of Crushing, Screening and Washing on both a Contract and Plant Supply basis.


Gypsum is generally found underground near deposits of Limestone or other minerals formed by evaporation.

Gypsum is found in many forms depending on location.

It also has many uses the most common use being the formation of Plasterboard Panels and Powder Plaster due to its fire and heat resistant properties.


Limestone is usually associated with Hills and Downlands and occurs in regions with other Sedimentary Rocks, typically Clays.

Commonly used in architecture, especially in Europe and North America, Limestone is readily available and relatively easy to cut into blocks or more elaborate carving. It is also long-lasting and stands up well to exposure.

However, it is a very heavy material, making it impractical for tall buildings, and relatively expensive as a building material. Despite this it is a popular material and its use is widespread.

Limestone has a wide range of diverse uses across several industries including; construction, agricultural & food products and environmental products.

Quarry Dust & Crushed Fines

When crushing stone there is a significant amount of -4mm fines produced, generally in the region of 40%. This byproduct, regardless of type of stone, is of relatively low value.

In many quarries all over the UK large stockpiles of unsold fines can be seen as they are low quality and suitable for few applications due to silt content. By washing these fines and using them as a Natural Sand substitute you will automatically increase their value.

If the fines are Limestone based natural silt and clays will need to be removed from the bottom end allowing them to meet Concrete Sand specification. Manufactured silt from the crushing process also needs to be removed.

Quarry Scalping

When quarrying stone there may be areas in the Quarry where there is a large amount of clay contamination. These occur particularly in Limestone Quarries where the clay sediments collect in fissures in the stone. This clay slows down the Crushing and Screen process, so it is scalped off at a size (generally 80mm – 100mm). This allows the clean stone to be crushed without fear of blocking. So Scalpings are essentially the off-cuts of a quarry; quarry waste for want of better words.

The resulting Scalpings contain a large percentage of saleable stone in them and when washed and scrubbed produce premium aggregate. Granite Scalpings have clay to a lesser extent, if at all, but are produced to speed up the crushing process as the smaller material in the Scalpings is slower and more difficult to crush and uses more power.


Sandstone is a sedimentary rock composed mainly of sand sized particles.

Some Sandstones are resistant to weathering yet are strangely easy to work. This makes sandstone a common building and paving material. Due to the hardness of the individual grains, uniformity of grain size and friability of their structure, some types of sandstone are excellent materials from which to make Grindstones, for sharpening blades and other implements.

Non-friable sandstone (e.g. Gritstone) can be used to make grindstones for grinding grain.


Slate is a fine-grained, Metamorphic Rock composed of Clay or Volcanic Ash. Slate is ‘cut’ into flats sheets of stone that can be sold however this process creates a large volume of waste; up to 90% in some cases.

Slate waste (shards, scalpings, dust and unworkable stone) that has been cast aside once the dressed slate has been prepared is used as a selected fill material in road and rail construction projects and the decorative market is large and with the varied colours, washing makes them a very saleable product.

Power X Equipment has installed a 100 tph Washing Plant to process the waste Slate at McAlpine Slate in Bethesda, North Wales.

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