Introduction
Mining process is an industrially based process that occurs in a natural environment. Its primary potential problems include disturbance of geological structure of the area. It generates enormous volumes of waste solid material and alters the ecology of the area involved, . This paper looks at the mining of phosphates in St Pierre Islands and its impacts. It also gives the possible mitigation measures together with underlying advantages and disadvantages.
Statement of the problem
St Pierre Island is a small, uninhabitable island to the north of Seychelles. The geologically unstable island is under attack by the sea waves. Its foundation rock that is made up of soluble phosphate minerals is dissolving in the sea water, . This dissolution threatens its existence. Its ecology is vulnerable because of its threatened existence. The biotic and abiotic components of the island are strongly dependent on each other for its survival. St Pierre Island was a rich source of phosphates and guano (source of gunpowder) up to early 1900s before mining activity begun. Although it had vast potential for phosphates and source of gun powder, the mining process posed a serious environmental challenge. The entire rocks making up the islands consisted of phosphates, . This means that the mining of the phosphates would demolish the entire island. The rate of extinction of the island became accelerated because both the sea attack and mining activity wasted its foundation rock. Moreover, the delicately thriving ecosystem was under threat because of mining. The phosphate rock from which the lush forest was deriving minerals was being depleted fast.
Historical basis of the problem
St Pierre Island was formerly covered with a dense forest of Pisonia grandis. These trees provided habitat for a large population of seabirds. The large population of seabirds covered the island’s coral rock with guano. Guano is the dung consisting of the faeces and urine of seabirds. It is highly effective manure because it has a high content of phosphorus and nitrogen and it lacks odor as compared with other forms of organic manure. Guano can be used as a source of nitrates for gun powder, .
Before the process of mining was begun in the islands, the island’s ecology had been thriving and growing towards a balanced ecological zone. The present biotic and abiotic components of ecology were compensating each other. The seabirds were producing fertilizer that sustained the trees growing lavishly. The mineral-rich rock and the splashing sea water provided minerals that sustained the biotic environment, .
The guano and the phosphate-rich rock were exhausted in the mining between 1906 and 1972. This converted the island from a densely forested island into barren, pitted landscape. The native trees that prevailed were cut down, and the seabird habitat was destroyed. The seabird population also declined. Very few natural trees could survive since the source of fertilizer had disappeared. The pits in the islands enhanced the extinction of the land. The exhaustion of the nitrates for gunpowder also denied the natural vegetation source of fertilizer. The growth of trees was, therefore, subdued.
The current trees are artificial trees made up of Casurina equisetifolia trees that were planted as windbreakers for the mining camp. These trees have managed to thrive on the barren island. Most plant species that were originally present in the island are now extinct. The native beauty of the island was destroyed by mining process, .
Mitigation measures
Despite the dying natural wildlife, some trees have been planted in St. Pierre Island. Examples of species of trees and plants introduced in the region include Gaillardia pulchella (Indian BlanketFlower), Agave sisalana (sisal), Carica papaya (Papaya), Musa (bananas), Asystasia gangetica (Chinese Violet) and Datura stramonium (Jimsonweed). Some of these species of artificial plants have established well on the islands. The dropseed grass species known as Sporobolus virginicus has done exceptionally well in the area. It may be a starting point for repopulation of the island with vegetation, .
The coral rocks making up the island are made up of phosphates and other minerals. These rocks are leeched at a faster rate by the swashing and back washing sea water. Consequently, the island is dissolved away faster than it is supposed. The first remedy to this problem is to stop mining the foundation rocks for phosphates. Once the mining process stops, the islands geology may be artificially altered by replacing the foundation rock with less soluble rock material, . The island has suffered deep undercutting process. This makes it both inhabitable and inaccessible. The center of the island has a depression at sea level. This depression encourages the extinction of the island. It should be filled u with an insoluble basement material. The feet of the island that is under the sea should be recovered from the deep under cuts. It is possible to recover the island just as artificial islands are being built elsewhere.
Benefits of mitigation
The trees are being replanted on the island. This implies that the ecology of the island could be restored once again. The growth of these plants is likely to attract a large population of seabirds. Once the seabirds repopulate the islands, the supplies of nitrates will be renewed, and the plants growth will be accelerated. The growth of forest will act as wind breaking. The strength of winds from the sea will be reduced, and the destruction effect will be minimized. This will stabilize the geology of the island because of reduce mass wasting effect of the sea forces.
St Pierre Island has been a source of guano from which gunpowder is derived. Once the ecology of the island is restored through planting the trees, the reserves for the raw material will be sustained. The island also serves as natural beauty scenery. Reforestation of the islands is likely to preserve the island for future generation. This is possible because the forest will stabilize the island by reducing the erosion effect of the sea water.
Some of the vegetation that originally prevailed in the islands could have medicinal value and are indispensable for research. These species of vegetation may be preserved and used for future research on medicines and vital chemicals. The island can also be used to predict the fate of similar islands that exist elsewhere. The study of the nature of extinction of the island could establish the fate of most islands. It also reveals the possible existence of islands in the earlier times.
Artificial islands are nowadays a lucrative venture. New islands are being built to act as a tourist destination. This island could provide a suitable foundation for the establishment of such an island. Instead of enhancing its extinction, it can be preserved for the purposes of extraction of guano for gunpowder, .
Disadvantages of mitigation
The island is difficult to access and is inhabitable. The process of restoring the island is an expensive undertaking. The entire island is made up of soluble mineral rock. The seabirds that were once found in the islands have since migrated out into nearby islands such as Seychelles. It will have to take a long time to revive the islands and for the birds to migrate back. The birds may not migrate back since the natural forests had been destroyed. The result is that the island may not be able to recuperate after all these efforts are put. The basement of the island consists of solvable mineral rock that may be difficult to reconstruct.
Conclusion
The rate of extinction of St Pierre Island is enhanced by the process of mining. The eroding effect of the sea has been naturally dissolving the island, but with the introduction of mining, the island extinction is faster. In order to preserve the island, the activity of mining must stop. Mining leads to destruction of natural ecological system of the forest and replacement with an n artificial one. The seabirds that once occupied it migrated away. The native ecology may be reintroduced with reforestation of the island. This will attract the seabirds back to the island. There are disadvantages of reclaiming the island. However, the potential benefits are far greater that the disadvantages. The island, in the future, may be used to explore under-the-sea-mining of phosphates. The area where the island exists could be rich in minerals such as phosphates. This explains the need to preserve the island, . It may also function as a resting place for future sea voyages. Moreover, the reforestation of the island with new species may not be desirable. The native species of vegetation may have greater value. Their extinction means that the potential of the natural vegetation may never be discovered after all.
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