Ethiopian Journal of Environmental Studies and Management Vol. 4 No.1 2011 The Geotechnical Properties Of Clay Occurrences Around Kutigi Central Bida Basin, Nigeria. 1Akhirevbulu O.E. and 2Ogunbajo M.I doi: 10.4314/ejesm.v4i1.3 Abstract The aim of this research project is to investigate occurrences of clay around Kutigi with an objective to determine its geotechnical properties. The study area (Kutigi) falls within the Bida Basin of Niger State. The methodology of research includes detailed mapping of the area, collection of clay samples, determination of; natural moisture contents, Atterberg limit, plasticity index, sieve analysis and coefficients of permeability. The results of the geotechnical analysis of the clay samples, suggests an average; moisture content of about 0.9% and 0.72%, liquid limit of about 19.9% and 22.1%, plastic limit of about 14.1% and 16.8%, plasticity index of about 5.8 and 5.3%, and a linear shrinkage limit of about 7.2% and 5.9%, for both locations A and B respectively. Results of the plasticity classification chart suggest that the soils are composed of inorganic clay of low plasticity. While results from the modified plasticity classification chart revealed three clay minerals; these include montmorillonite (35%), illite (35%) and kaolinite (30%). A simple comparison of sieve analysis results suggest soils from location A to be more coarse-grained within the coarser half of the sieves (i.e. between 5mm to 0.3mm), and also more fine- grained in the finer half of the sieves (i.e. between 0.01mm to 0.075mm) than soils from location B. The grain-size curves were classified as those of immature residual soil. Their analyses suggest the texture of the soil to be predominantly sandy. Results of the estimated coefficient of permeability, classified about 25% of the soils as coarse sand and about 75% of the soils as fine sand. These suggest the soils to be predominantly sandy and highly permeable. The results of the geotechnical investigation of the Kutigi clay deposits and an earlier mineralogical and geochemical analysis suggest that the clay can be utilized in the manufacturing of ceramics, refractory bricks, paper, fertilizer and paint. Introduction lay and clay minerals have been The study area (Kutigi) is situated in Cmined since the Stone Age and has Lavun Local Government Area of Niger State, been indispensable in architecture, in industry, within Bida basin (one of the sedimentary and agriculture. Today they are among the most basins in Nigeria). It lies between longitude 5 o important minerals used by manufacturing and 35 1 E and 5 o 39 1 E and latitude 9 o 10 1 N and 9 o environmental studies. Clay has a wide spread 13 1 N of Nigeria on sheet 183 Egbako S.W occurrence in the world. In Nigeria, clay is (Fig. 1.). It covers an area of about 39.88km 2. widely distributed though not always found in Kutigi is the major town in the area, while the sufficient quantity or suitable quality for surrounding villages include Kusogi, Shebe, modern industrial purposes. It occurs both as Makufu, Fazhi and Ruga. The physical residual and sedimentary clay. More than 80 landform of Kutigi area is made up of flat-lying clay deposits have been reported from all parts to gently rolling plains. The monotony of the of the country. Clay deposits occur in Abak, landscape is however broken by residual hills, Akwa Ibom State, Uruove near Ughelli in Delta which are either conical or flat-topped. The State, Ifon in Ondo State, Mokola in Oyo State, area is mark by a NW−SE and a NE−SE Sokoto in Sokoto State, Gombe in Gombe running ridges that are prominently composed State, Dangara in Niger State, Umuahia in Abia of laterite. The ridges ranges from 15m to 50m State, Onitsha in Anambra State e.t.c. in height as observed along the road cutting Almost every State in Nigeria has at least one between Kutigi town and Ruga village.The known deposit of kaolin. In Anambra State terrain is mostly covered by laterite and fairly there is the Ozubulu deposit, Darazo kaolin by soil and sandstone as a result of the deposit in Bauchi, Akpene-Obom deposit in weathering activities that have depleted the Cross River State, Kankara in Kaduna State hills and ridges. The area is particularly drained e.t.c. The three most extensively studied by river Toro which run near Kusogi village deposits are the Ozubulu kaolin deposits, and flow in the NE direction of Egbako SW. Kankara deposits and the Major Porter Many insequent streams that enters river Toro deposits, in Plateau State. The focus of this as tributaries are seasonal and forms a dentritic work is to investigate clay occurrences around drainage pattern which strongly suggest that the Kutigi as well as to determine its geotechnical terrain is composed of lithological, structural properties. and topographic homogeneity basement, which Study Location. created fault patterns trending northeast- 1Department of Physics, Ambrose Alli University Ekpoma, Edo State, Nigeria. [email protected] 2 Department of Geology, Federal University of Technology Minna, Niger State, Nigeria 25 The Geotechnical Properties Of......... Akhirevbulu And Ogunbajo EJESM Vol. 4 No1 . 2011 southwest and northwest-southeast (Kogbe, Alabi, (2005) identified two clay deposits in 1981). A rift origin for the basin has been Kutigi. The clay deposits he said were of postulated by Kogbe (1981) whilst Whiteman varying thickness, capped by thin layer of (1982) suggested the basin to have been formed lateritic soil and vary from white to dirty white from simple cratonic sag. The sedimentation in colour due to stains from the over burden data presented suggest that the central Bida laterite. basin was formed by rifting or by cratonic The first hill visited (which he called location sagging. A) is located behind ministry of works north Literature Review east of Kutigi town. The second hill visited Adeleye (1971), and Adeleye and (which he called location B) is located behind Dessauvagie (1972) identified clays in the Sharia Court, north west of Kutigi town. He Middle Niger Basin or the Nupe sandstone now explored and estimated the reserve extent of the renamed the Nupe Group. They studied the clay deposits. Geophysical evidence of Alabi, Stratigraphic succession in the area and (2005) suggests that the total reserve of the reported the direct overlying of the basement Kutigi clay deposits is estimated to about complex by a coarse conglomerate, clay- 672,579 tons, with an aerial extent of about 57, sandstone admixture, boulders etc of 400m 2 of clay bed in location A, and also an sedimentary origin. These, according to area extent of 300m 2 in location B. The results Adeleye, were themselves overlain by of his physical analysis show medium plasticity sandstone, and subsidiary claystones, index average of 30%, Specific gravity of 2.61 conglomerate and siltstones. The University of and medium linear shrinkage average of 2.68%. Ife (Adegoke, 1979) and Ahmadu Bello His chemical analysis show the high dominance University Consultancy team also studied clays of SiO 2 66%, Al 2O3 26.87%, TiO 2 1.45%, Fe 2O3 in parts of Bida basin. Adegoke, (1979) worked 0.99%, while the remaining 4.69% represents on the structural properties of these clays at other elements in trace amount. temperatures of 600 oC -1000 OC.All the clay Average mineralogical composition of occurrences investigated fall within the analyzed clay samples show the dominance of Cretaceous Maestrichtian in middle Niger basin kaolinite 85%, quartz 13% and K- feldspar as (Bida Basin). The two main types of clays in trace. He observed that Kutigi kaolin was found the area are the earthy brownish to red lateritic to be similar to the Oza-Nagogo kaolin by clays and the grayish ball clays. There are also simple comparison with some well known the whitish and silty kaolinites. The lateritic kaolin deposits. From various tests conducted clay occurs beneath thin to thick covers of on Kutigi clay, he reported that Kutigi clay laterite on residual hills. The earthy lateritic occur as residual clay due to the weathering of clays are ubiquitous in occurrence. The grayish feldspar from feldspathic sandstone and its high ball-clays within the Bida basin occur on quartz content. The clay, which is alluvial plains of rivers. These are seemingly predominantly kaolinitic from its mineralogical secondarily derived clays deposited from composition, was noted to be suitable as raw suspension load in the streams. They are material to the ceramic, paper, refractory and generally plastic in nature. There are other paint industries respectively. similar clays but those are derived from the Research Methodology feldspar rich basement rocks (Adegoke, 1979). Detailed field mapping was carried out Sedimentary kaolin deposit are known to around Kutigi in order to establish the local occur in Nigeria mainly as beds, lenses or geology of the area. The method of bands within the Cretaceous and Tertiary investigation involved an intensive fieldwork, sedimentary sequences in the Sokoto, Benue, which lasted for eight days. For the purpose of Chad and particularly the Niger Delta Basins. this study, a map extract was adopted from a Prominent sedimentary kaolin deposits reported topographical map on sheet 183 of Egbako SW from some of these basins include among of Niger State at a scale of 1: 50,000. The map others, those at Nsu, Ifon, Enugu, Ozubulu, extract, which now constitute the base map of Oza-Nagogo, Ubiaja, Sapele and Warri the study area, was enlarged to a scale size of 1: (Waudby- Smith, (1957); Proceng Consultants 12,500. It covers an area of about 39.88km 2. report, (1974); Faseke, (1981); Aderibigbe and The area was divided into four equal squares to Chukwuogo (1984); Coker (1986); Enu and ensure thorough mapping.