Mining and Quarrying in Rwanda
Senior 2 · Geography and Environment
Mining and Quarrying in Rwanda
Lesson 2 of 3
20 min
Every new house, school and road in Rwanda starts with material dug from the ground: sand from river beds, stones broken from hillsides, clay moulded into bricks. Rwanda's building boom depends on quarrying, and so does its cement factory. Quarrying also scars valleys and hills if it is not controlled. This lesson explains what is quarried, where, and why.
A quarry is an open pit from which rock, sand, gravel or clay is dug for building. Quarrying is therefore a form of extraction, but it differs from mining in several ways:
| Mining | Quarrying |
|---|---|
| Extracts valuable minerals (tin, gold) | Extracts bulky rock, sand, gravel and clay |
| Often underground, in tunnels | Always at the surface, in open pits |
| Small tonnages with a high value per tonne | Huge tonnages with a low value per tonne |
| Products are often exported | Products are used near where they are dug |
| Material | What it is | Where | Uses |
|---|---|---|---|
| Basalt | Dark, hard volcanic (igneous) rock | The volcanic north-west (Musanze, Nyabihu, Rubavu) | Building stone; crushed for concrete and road foundations |
| Granite | Hard, speckled igneous rock made of large crystals | Outcrops in several parts of the country | Building stone, paving, crushed aggregate |
| Limestone | Sedimentary rock made of calcium carbonate | Rusizi District, near Bugarama | The main raw material for cement at the Cimerwa factory; lime to reduce soil acidity |
| Sandstone | Sedimentary rock of cemented sand grains | Ridges in several regions | Building blocks, walls |
| Laterite (murram) | Red, iron-rich layer formed by deep weathering | Hill slopes across the country | Surfacing earth roads; pressed blocks |
| Clay | Very fine sediment | Valley bottoms and marshes | Bricks, roof tiles, pottery |
| Gravel and sand | Loose rock fragments and grains | River beds and valley floors, such as the Nyabarongo; open pits in Muhanga | Concrete, mortar, plaster, roads |
A builder in Kigali needs one truckload of sand. It costs 60,000 Frw at the pit, and transport costs 2,500 Frw per km. Pit A is 20 km away; pit B is 60 km away. Compare the delivered costs.
Tip
Memory hook: mining is for value, quarrying is for volume. When asked to locate a quarry, think "close to the market", because transport is the biggest cost.
Solution: quarrying is always open-pit while mining may be underground; quarrying extracts bulky, low-value materials while mining extracts valuable minerals.
Solution: limestone, near Bugarama in Rusizi District, for the Cimerwa factory.
Solution: basalt is a volcanic rock, formed from lava of the Virunga volcanoes, which are in the north-west.
Solution: 60,000 + 35 × 2,500 = 60,000 + 87,500 = 147,500 Frw.
Solution: clay: bricks and tiles; laterite: surfacing earth roads.
Summary
Sources and credits
The comparison table, the table of quarried materials, the worked example (illustrative figures) and the practice items are written by Ganzaa.
This lesson adapts CC BY-SA material and is shared under CC BY-SA 4.0.
