What is a quarry?
A quarry is a place where rocks and construction aggregate including sand, gravel and crushed stone are extracted from the surface of the Earth. A quarry is a type of mine called an open-pit mine, because it is open to the Earth’s surface. The most common purpose of quarries is to extract stone for building materials.

Rock is an important natural resource in Malta. Here we find two types of quarries, those known as hard rock quarries which excavate mostly aggregate such as sand, gravel and crushed stone from the Upper and Lower Coralline Limestone layers and soft stone quarries known locally as tal-Franka. This is obtained from Globigerina Limestone and is cut into building blocks of stone. Quarrying is crucial for the construction industry which depends on it. Quarrying generates a lot of work in the construction industry, not only for those employed directly in quarrying, but also for many others whose work depend on the construction sector.

Soft stone quarries
In the past the excavation and cutting of stone in quarries used to be done with hand tools. Nowadays this same work is done more quickly and with less fatigue with the use of machinery. Two main machines are used, the trench machine which cuts the stone from above according to the depth or height of stone required; and the lower machine which cuts the stone horizontally. Meanwhile fine dust is produced called fine stone dust, xaħx in Maltese, which is mixed with cement and water to form mortar which is used by the stone masons during construction. This video shows rock are cut from Globigerina Limestone.

Hard stone quarries
In coralline limestone quarries, the rock is excavated by means of dynamite. Machines will then break it up into smaller pieces which are then dropped into a crusher that grinds them into aggregate such as gravel or building sand. Aggregate derived from lower coralline limestone is much sought for the production of pre-fabricated concrete roofing and for street tarmac, concrete and bricks. The first video below shows how rock is blasted by the use of explosives and the second video shows how machines crush the blasted rocks to form aggregates of different sizes.

Now answer the following questions.
The building industry in Malta makes use of two main types of rock, one is soft while the other is rather hard.
• Name the two types of rock used by the building industry in the Maltese islands.
• Why is quarrying considered to be a very important economic activity in Malta?

Look at the photo below.

• What type of quarry is shown in the picture?
• From which rock layer is this rock excavated?
• Name the material obtained from such a quarry.

Look at the photo below.

• What type of quarry is shown in the picture?
• From which rock layer is this rock excavated?
• Name the material obtained from such a quarry.

As we have already seen quarrying has positive economic effects by providing jobs to many workers however it has some negative social and environmental effects or impacts. Watch this video which will explain clearly what is quarrying, its economic advantages and how does it affect us and our environment.

• Now list all the economic benefits and the social and environmental disadvantages of limestone quarrying.

Along the years, a number of old and disused quarries have been rehabilitated. Some of them have been filled up with construction waste and later covered with a soil layer for agricultural use. Others have been directed for industrial use having concrete batching or tarmac plants. Others have been turned into large reservoirs for rainwater storage which is then used as second-class water.

Now work out the worksheet entitled Limestone Quarrying Worksheet, available in the resources section.