Geoelectrical and Geotechnical Investigations of Subsurface Corrosivity in Ondo State Industrial Layout, Akure, Southwestern Nigeria

Fifty two vertical electrical sounding (VES) data and six subsurface soil samples were collected at Ondo State Industrial Layout, Akure, south-western Nigeria in order to determine the subsurface corrosivity. The VES results delineated 3 to 5 geoelectric layers across the area, which correspond to topsoil, weathered layer, weathered basement, weathered/fractured basement and the presumed fresh bedrock. The layer resistivity values range from 22 to 602 ohm-m, 7 to 2468 ohm-m, 17 to 436 ohm-m, 25 to 39 ohm-m and 203 to 10023 ohm-m in the topsoil, weathered layer, weathered basement, weathered/fractured basement and the presumed fresh bedrock respectively. The iso-resistivity maps at depth slices of 1 and 2 m show that the northeastern, southeastern and the upper central part of the area are non-corrosive (above 350 ohm-m) to slightly corrosive (250 - 350 ohm-m), while the lower central, northwestern and southwestern parts of the area are moderately (150 - 250 ohm-m) to strongly corrosive (60 - 150 ohm-m).  Soil sample analysis shows liquid limit results that  vary from 37.6 to 59.7, while the plasticity limit results vary from 29.3 to 42.5 and all the plasticity index plots were below the A line indicating presence of non-plastic clay. The natural moisture content values vary from 21.4 to 35.5 %. The 2 m depth slice isoresistivity map and clay plasticity factor were synthesized using additive model to generate subsurface CR-index corrosivity model map which indicates that the northwestern, north-eastern and southern parts of the area are moderately (0.4 - 0.6) to strongly corrosive (0.6 - 0.8), while the upper central area and the flanks are slightly corrosive. The moderately and strongly corrosive zones correspond to the low elevation and water logged zones of the study area. The corrosivity model map was validated by the pH and corrosivity data. Keywords: Geotechnical, Liquid Limit, Plastic Limit, Plasticity Index, Clay Plasticit

Quality Evaluation of Udane–Biomi Coal in the Northern Anambra Basin of Nigeria

Communication in Physical Sciences 2021, 7(4): 444-453 Authors: Felix Bamidele Fatoye* and Michael Adewale Ibitomi Received: 29 November 2021/Accepted 08 December 2021 Coal is a significant fuel for several industrial operations, however, its scope of application depends on some quality parameters. In this study, a geochemical investigation of Udane–Biomi (in Northern Anambra Basin) coal deposit has been carried out to ascertain its potential relevance to possible industrial applications. Results from the proximate analysis indicated that the average composition of the coal includes 4.49 % moisture, 76.06 % ash, 11.76 % volatile matter and 7.69 % fixed carbon. The ultimate analysis also reveals that coal consists of 10.58 % carbon, 1.66 % hydrogen, 0.29 % nitrogen, 6.82 % oxygen, 0.12 % sulphur and 0.02 % phosphorus. The average heating value of the coal is 1891Btu/1b and a free swelling index of 0.0 (zero). This observed composition of the investigated coal contradicts with data expected for cooking coals. However, coal is appropriate for electricity generation, heating boilers and ovens in industrial process heating. Coal can also be useful in the cement, glass, ceramic, paper and brick industrie