ABSTRACT
The study examined positive and negative environmental impacts of the continuous removal of river sand, pit sand and gravel from sampled areas surrounding Maiduguri developing Central Business District, malls and private properties in city.
Quantitative and qualitative research designs that is questionnaire survey, oral interviews, field observation and measurements were used to collect data from selected sampled points. Mafa and Ditlhakane rivers were selected because they are nearer to Maiduguri and most river sand is mined from these rivers. More points were sampled from open areas in Marte, Kopong and Bela Bela farms where pit sand and gravel are mined. Convenience and purposive sampling methods were used to pick questionnaire survey respondents (175) from Marte and Mafa villages where people affected lives.
Findings of the study highlighted that river sand was mined most from rivers near Maiduguri compared to pit sand and gravel because of its multi uses. Mining is important for economic development, to construct durable, modern structures, employment creation and revenue collection but removal of river sand leads to deepening and widening of rivers. Artificial rivulets are formed as resource is extracted uncontrollably. Pit sand and gravel are extracted from open areas creating uncovered deep pits, which caused of accidents to children and livestock. Erosion and environmental degradation occur due to continuous mining. Miners dispose waste on open areas and riverbeds causing land pollution. Dust and noise pollution from tipper trucks ferrying sand and gravel are a cause of concern to villagers as the trucks move even at night, disturbing sleep.
CHAPTER ONE
INTRODUCTION
1.1 Background of study
Soil is a cheap natural resource made up of gravel, sand, clay, loam which constitutes the different types. Pit sand, river sand and gravel are components of soil which take years to be formed but extracted in a matter of days. Sand and gravel are underground geological resources formed from eroding mountain rocks carried by streams and rivers. According to Mwangi (2007), soil has many uses, it is needed for agriculture, as a habitat and in construction but the genesis of cash economy brought many profit driven companies to be involved in its mining both legally and illegally with some having no regard for the environment. Soil mining and harvesting has both positive and negative environmental impacts.
Stebbins (2006) gave the background to formation of sand and gravel deposits, a legacy of the continental ice sheets that melted thousands of years ago. As the ice melted, fast moving rivers were formed leaving deposits of coarse sand. The rivers ran into the sea, large deltas were formed with layers of sand and silt. Now there is no more ice and rivers but scattered deposits of sand and gravel which are used as important natural resources. Sand and gravel deposits are porous, water can pass through this geological material, making it a source of high quality water (Stebbins,2006).
Draggan (2008) discussed sand and gravel as commodities used in industry especially construction. In construction, the components are used either mixed with other materials or as is, while in industry, sand and gravel are used in production of other materials like aggregates. Sand mostly quartz grains (Silicon dioxide) formed from weathering of granite rocks. The quartz grains accumulated in rivers, streams, deltas and beaches. Therefore, quartz is very valuable as sand because of its silica content. The physical properties of sand and gravel particularly in abrasive property make the resources useful for traction on icy roads, roadways and rail road including sand blasting (Draggan, 2008).
Mines and Minerals Act (1999) highlighted that the Botswana depends on mining of minerals but there is also mining of river sand, pit sand and gravel done both legally and illegally. For thousands of years, various soil components had been used for construction of roads and buildings. Demand for soil in the country has increased today which has led to the excessive stream and land extraction of pit sand, river sand and gravel causing land degradation, riverbank deepening and loss of ecosystems (Mbaiwa, 2008). An article in the Daily News (2011) reported a case involving residents of Mafa, a village about fifteen kilometres Northwest of Maiduguri who were up in arms due to continuous extraction of sand from the nearby river. They complained of deep pits left on bare land, air and noise pollution caused by tipper trucks transporting soil to Maiduguri. The article noted that a lot of land is required for mining the abundant resource. As more impacts are felt, there is need for immediate environmental control and restoration. Soil mining is an environmental issue worldwide. There is need to consider sustainable use of natural resources in project development through sound sand and gravel extraction. The activity is of great concern to environmentalists as it has more negative impacts thanpositive.
1.2 Statement of the problem
Maiduguri is expanding at an alarming rate. Expansion means growth in infrastructure, construction of new roads, commercial malls and residential areas (Wokorach, 2002). There is need for use of various soil components such as pit sand, river sand and gravel from various sites surrounding the city. People seem to be extracting these soil components excessively without considering the impact on the environment. Most likely, there is overexploitation of soil leaving deep pits on bare ground while rivers are widening daily. Soil mining has become a daily sight with tipper trucks carrying pit sand, river sand and gravel from rivers and open fields. It seems there are no strict rules to govern soil extraction. Deep and wide pits are left when pit sand and gravel are collected, riverbeds widen and deepen after removing river sand, affecting aquatic while gravel removal destroy ecosystems, forests and agricultural land (Mbaiwa, 2008). Pit sand organisms is collected from Marte, river sand is from Maiduguri rivers while gravel is extracted from Maiduguri. There seemed to be a problem of environmental alteration, ecosystem and agricultural land destruction as well as riverbed and bank degradation due to excessive removal of pit sand, river sand and gravel which prompted the researcher to investigate the depth of these environmental impacts.
1.3 Research Objectives
To assess and evaluate environmental impacts of mining pit sand, in Maiduguri
Specific objectives :
1. To assess and compare the soil component mined most for construction.
2. To measure and analyse the size of pits where pit sand and gravel are collected.
3. To evaluate the positive and negative environmental impacts of mining river sand, pit sand and gravel for urban development.
4. To make recommendations on sustainable mining of soil which reduce negative impacts on the environment.
1.4 Research questions
1. Which soil component is mined most?
2. What are the positive environmental impacts?
3. Which are the negative environmental impacts?
4. What recommendations can be given to reduce the negative impacts?
1.5 Significance of study
The research was meant to obtain increased understanding of the potential positive and negative impacts of sand mining and gravel extraction in stream, bare fields and riparian habitats. The study concentrated on exposing the environmental impacts of mining pit sand, river sand and gravel extraction for Maiduguri. The researcher found it necessary to carry out a study on finding the environmental impacts of soil extraction, both positive and negative, in pursuit of knowledge and for public good. The outcomes of the research are valuable solutions to rehabilitation of land where soil is extracted and mitigation of negative effects. This research was also meant to provide guidelines for evaluation of potential positive and negative environmental impacts. Recommendations had been made on sustainable use of the environment while supporting the positive impacts. Alternatives to sand had been suggested.
1.6 Limitation of study
The author faced challenges during the study which limited accuracy of results. Few villagers formed the sample to represent the populations due to shortages of human resources. Only 175 respondents formed a sample which participated in the survey. One hundred and five respondents were picked from Marte while seventy were Mafa villagers. Some participants were not cooperative and unwilling to answer questions truthfully or left some questions unanswered leading to misrepresentation and inaccurate results.
Another limiting factor was that the researcher is employed so time to collect data from affected areas was not enough therefore data collection was mostly done during the weekends. Mining sites are in dangerous bushy areas, researcher, could not go alone, so had to be accompanied by local police officers on each visit.
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Item Type: Project Material | Size: 121 pages | Chapters: 1-5
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