Department of Mining Engineering

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A Review of Exploitation Techniques of Barite Deposits of Nasarawa State, Nigeria
(2022) Abdulraman Sikiru Ottan; Itohan Otoijamun; Adedoyin Adeonipekun Dele; Azikwe Peter Onwualu
The geometry and types of barite deposit affect mining economics and processing complexity. Nasarawa state barite deposits are cavity filling types with inherent complex geometry that is beyond the comprehension of the workforce (artisanal miners) involved in the production value chain. This study reviewed the barite production from Nasarawa State; and the current exploitation techniques were evaluated through monitoring of field operations; questionnaire; and personal interview. The questionnaire addressed critical issues relating to exploitation of barite which include management and control of barite mining and processing operations; level of technical skill; mechanization; mine safety and hygiene; mine productivity; host community relation; and mineral economics related matters such as monetization of mined products. Twelve (12) barite mining locations were visited, and eighteen (18) barite veins were studied. The veins run almost parallel to each other and averagely 80cm thick, 1m wide, and overlaid by about 20m overburden of varying materials (laterite, and sandstone, etc.). Consensus submission of the respondents and interviewees is that lack of technical skill and support hinders efficient operations at the mine sites. Barite mining pits are abandoned prematurely and inexhaustibly resulting from poor exploitation techniques due to lack of adequate profiling of the deposits that impacts negatively on sustainable development of Nasarawa state barite deposits. It becomes imperative therefore to delineate the deposits and adopt appropriate exploitation technique while enhancing the technical skills of the workforce through human capacity development.
ASSESSMENT OF PHOENIX DACTYLIFERA SEED EXTRACT AS A GREEN INHIBITOR FOR THE CORROSION OF MILD STEEL IN AN ACIDIC SOLUTION
(2024) Y. L. SHUAIB–BABATA; I. V. AYINDE; Y. O. BUSARI; R. A. YAHYA; M. O. AMEEN; S. O. ABDULRAMAN; I. O. AMBALI; K. S. AJAO; T.A. NURUDEEN; J. O. ADEGBOLA
Metal corrosion continues to be a major problem for a variety of sectors, prompting the investigation of innovative and environmentally acceptable corrosion prevention techniques. This study examined the potential of Phoenix dactylifera (date palm) seed extract as a green corrosion inhibitor for mild steel in an acidic environment (HCl). The study thoroughly investigated the inhibitory effects of various extract concentrations (0.2–1.0 g/l) on corrosion rate and efficiency across exposure times of 168 hours using both gravimetric and Tafel polarisation methods. According to experimental findings, extract concentrationand corrosion inhibition effectiveness were strongly correlated. Corrosion rates were significantly reduced at higher extract concentrations, supporting the extract's potential as a powerful inhibitor. From the results, optimum inhibiting efficiency of 96.4% with concentration of 1.0 g/l after 72 hours of exposure and 61.99% from 1.0 g/l extract were observed for gravimetric and Tafel polarization, respectively. By emphasizing the extract's capacity to adsorb components onto the steel surface and create a shield that prevents corrosion, the research also contributes to the evolving field of corrosion science through introduction of a natural and eco–friendly corrosion inhibitor.
Characterization of a Feldspar Mineral from Adogo, Ajaokuta Deposit
(2022) Y. L. Shuaib-Babata; S. O. Abdulraman; Y. O. Busari; I. O. Ambali; K. S. Ajao; O. M. Yusuf
This study considered the suitability of Adogo feldspar deposit in Kogi State, Nigeria for glass and ceramic production. The feldspar's sample was characterised through analysis of its physical, chemical and mineralogical properties. The results of the physical analysis showed that the mineral has a bulk density of 1.3551 g/cm3 and tapped density of 1.5209 g/cm3, which was used to determine the compressibility index and Hausner ratio. The index shows that the powdered mineral has a good flow character. The result also revealed that the mineral has a very low percentage of moisture content (1.75%) and clay content of 2.9%. Meanwhile, the chemical analysis showed that the feldspar mineral has dominant elements of Silicon (70%) and Aluminium (20%), with 73% and 23% oxides of silicon and aluminium respectively, negligible values of other elements and oxides in the feldspar. The mineralogical analysis revealed that the feldspar deposit was of low-grade soda feldspar, while the phases present showed that the mineral was a low-grade feldspar Albite Feldspar. Though, the physical and chemical properties of the feldspar revealed the potential of the feldspar as a suitable raw material in ceramics and glass industry but further beneficiation was needed to meet suitability for the production of ceramic and glass.
CHARACTERIZATIONS OF SOME NIGERIAN BED MATERIALS FOR FLUIDIZED BED COMBUSTOR
(2009) I. I. Ozigis; Abdulraman Sikiru Ottan
Bed materials processing involves solid minerals reduction to sizes of about 100-600pm and density of about 1400-3000 kg/m". Apart from the physical criteria, the chemical properties were also essential in respect of its absorbent and agglomeration effects in the fluidized bed combustor. In this work, we present the process technology to produce and select bed materials from Nigerian solid minerals. Firstly, the chemical composition of the various processed bed materials were determined using wet chemical method. Secondly, we subjected the materials at 100um to dustiness test which provided the proportion trapped by the cyclone and filter. Nigerian bed materials were high in qualities and they met the requirements of fluidized bed combustion technology.
Comparative analysis of drilling performance of kymera and PDC bits in salt formation
(2020) Alaba O.C.; Abdulraman S. O
The study compares the drilling performance of Kymera and PDC bits in salt formation using River and Delta State Continental Shelf of Nigeria as a case study. The measurement while drilling (MWD) and the logging while drilling (LWD) methods were used to measure the real time well drilling operation. well formation and drilling statistics. The data obtained from the Ogbaimbiri. Ossiomo. Utorogu and Okporhuftu wells have the penetration rate of 6.2 m/hr. 5.9 m/hr. 12.2 m/hr. 6.3 m/hr for Kymera bit and 4.2 m/hr. 3.4 m/hr. 6.8 m/hr. 3.9 m/hr for PDC bit respectively. The pearson correlation coefficient has a value of r = 0.897. n = 4. p<0.05 and r = 0.784. n = 4. p<0.05 for both kymera and PDC bits. The results established a strong and positive correlation between the penetration rate and distance drilled in each bit. It also shows that the higher the penetration rate the more the distance drilled by each bit. The study concluded that the Kymera bit was more efficient as it was able to penetrate the different formations with a lesser time and at a greater penetration rate.
CORRELATION OF BLASTING PERFORMANCE WITH LOADING AND CRUSHING TIME TO MINIMIZE ENERGY CONSUMPTION
(2020) Olanrewaju Alaba; S.O. Abdulraman
Blasting performance with loading and crushing time were correlated in order to minimize energy consumption in quarry operation. A measure scaled object was placed within the muck pile of blasted rock fragments. Digital camera was used to take the photograph of the scaled object and the blasted rock fragments before the commencement of loading and crushing operations. The data collected were subjected to fragmentation analysis using split desktop App while the correlation analyses were carried with Microsoft Excel App. The fragmentation and distribution analysis showed that the fine cut off sizes are 8.75 cm, 9.55 cm, 7.58 cm, 8.58 cm and 11.75 cm while their mean size distribution are 35.99 cm, 10.25 cm, 24.86 cm, 16.78 cm and 16.10 cm respectively. The R squared values (R2) obtained during the correlation of digging time with size of fragmentation passes (P50), mean deviation and bucket passes were given as 0.94, 0.39 and 0.63 with p-values of 0.00, 0.34 and 0.82 respectively. Consequently, the R2 values during the correlation of crushing time with P50, mean deviation and range were specified as 0.64, 0.62 and 0.27 with p-values of 0.00, 0.11 and 0.07 respectively. The study therefore established that only the regression equation for P50 is statistically significant while statistically insignificant for mean deviation, range and number of bucket passes.
Corrosion Inhibition Efficacy of Hybrid Organic Extracts from Prosopisafricana and Citrulluslanatus on Mild Steel in Acidic Medium
(2023) Yusuf Lanre SHUAIB-BABATA; Israel Victor AYINDE; Yusuf Olanrewaju BUSARI; Mubarak Oloduowo AMEEN; Raheem Abolore YAHYA; Ibrahim Owolabi AMBALI; Ishaaq Na’allah AREMU; Sikiru Ottan ABDULRAMAN; Kabiru Suleiman AJAO; Abdulateef Alabi GARUBA
Each of Prosopis Africana pod extract (PAPE) and Citrulluslanatus (WMPE) performed quite well as green inhibitors in the electrochemical corrosion in acidic solution at ambient temperature in previous research. However, the hybridization of these compounds was varied with the concentration ratio in this study to optimize the efficiency of the green inhibitor in a hydrochloric acid medium using mild steel. The extraction process of the inhibitor samples was carried out with the Soxhlet apparatus using n-hexane as the solvent. Furthermore, the potential inhibition efficiency was monitored using various corrosion measurement techniques at room temperature. The inhibitive response of the extracts could be attributed to the adsorption of the extracts’ components on mild steel surface by physisorption mechanism according to the Langmuir adsorption isotherm model. The results revealed that inhibition efficiency (IE%) depends on the concentration of the extracts. The peak IE% values were obtained with a hybrid ratio of 3:1 (PAPE: WMPE) for gravimetric technique. The Tafel polarization and gasometrical measurement technique is 96.7%, 98.5% and 83.1% respectively at the concentration of 1.0 g/L, which are above the peak IE% for PAPE (93.7%, 80.96% and 77.8%) and WMPE (92.7%, 80.5% and 75.6%).
CRUSHING PLANT PERFORMANCE EVALUATION USING OEE
(2019) Abdulraman S. O; Ozigis I. I
Over the years, economy of scale has been adopted as a panacea to the poor return on investment (ROI) in aggregate quarry establishments. This has forced quarries to increase their capital expenditure (CAPEX) due to acquisition of large capacity equipment that are often very costly. Low commodity (chippings) prices and high energy costs have further compelled quarry operators to adopt cost effective operating strategy. The true cost effectiveness of aggregate quarries lies in their performances and life cycle costs, of which their performances depend on their equipment availability, utilization and efficiency. Quarry equipment availability, utilization and efficiency are therefore very important performance indices that a quarry operator needs to constantly evaluate to work within the threshold, if the quarry business must deliver high ROI or quick payback which ultimately is the prime objective of any business. Overall Equipment Effectiveness (OEE) is a well-known performance metric which combines availability, utilization and efficiency for the evaluation of crushing plant effectiveness in an aggregate quarry. The performance metrics of F and P quarry, Abuja, Nigeria have been determined, and the plant availability (A); utilization (U); efficiency (E); and OEE evaluated to be 77.55%, 65.08%, 33.15%, and 16.62% respectively. The OEE value is far below the global best standard of 85% for manufacturing system, and reflects the influence of plant availability, utilization and efficiency on OEE value. However, there is no literature on the use of OEE for granite crushing plant, though; attempts have been made to use the metric on drilling machines, loading and haulage facilities. This paper presents a procedure for estimating OEE of a crushing plant; explains the cause for poor OEE in Nigerian plants during rainy season; and reason why Nigerian crushing plants should run with generators of adequate power outputs; and not on external power source.
Determination of an Appropriate Exploitation Method for Sobi and Oloje Clay Deposits for Production of Bricks and Ceramic Work; Ilorin, Nigeria
(2012) Abdulraman S. O; Olaleye, B.M
Current exploitation practice of llorin clay deposits in Nigeria has been investigated to be largely dominated by female artisans (old and young) who depend solely on crude implements such as sticks, spades and baskets with resultant premature abandonment of mined out pits. Exploratory pits were dug to probe the profile of the deposits in the two locations (Sobi and Oloje) and the borehole data of the deposits were used to produce isopach map of the deposits. Several equipment combinations were considered for the exploitation of the deposits. Stripping by bulldozer was favoured to be most appropriate.
EFFECTS OF SAWDUST PARTICLES REINFORCEMENT ON THE MICROSTRUCTURAL, PHYSICAL, AND MECHANICAL PROPERTIES OF CEMENT-BASED COMPOSITES: AN EXPERIMENTAL STUDY
(2024) Kabiru MUSTAPHA; Sikiru O. ABDULRAMAN; Moyosoreoluwa O. KING-OKUNEYE
This study investigates the effect of varying sawdust reinforcement volumes on the physical and mechanical properties of Portland cement composites. Sawdust from a local sawmill in Moro, Kwara, Nigeria, was incorporated into cement composites at volume fractions from 40% to 90%. Composites samples were produced for physical, mechanical and microstructural characterizations. Results showed that water absorption increased with higher sawdust content, peaking at 41.78% for 90% sawdust composite, and bulk density also rose, reaching a maximum of 193.33 g/m. at 90%. Apparent void volume generally decreased with increasing sawdust content. Optimal mechanical properties were observed at 60% sawdust content, with the highest compressive strength of 20.32 MPa, flexural strength of 8.36 MPa, and fracture toughness of 0.85 MPa.m1/2, while hardness decreased with increasing sawdust, peaking at 42.99 HRBS at 40% sawdust. Microstructural analysis using scanning electron microscopy (SEM) revealed a uniform distribution of sawdust particles within the cement matrix, with improved interfacial bonding observed at the optimal 60% sawdust content, contributing to the enhanced mechanical properties of the composite. In conclusion, 60 vol.% sawdust reinforcement is optimal for enhancing the mechanical performance of Portland cement composites, offering a balance between strength and sustainability, suggesting its potential as a cost-effective, eco-friendly reinforcement for cement-based materials in sustainable construction practices.
Equipment Maintenance Management Audit of Some Granite Aggregate Quarries in Part of South - West Nigeria.
(2016) Abdulraman S. O.; Olaleye B.M; Saliu M.A
This paper analyses an existing maintenance management system in some selected typical granite aggregate quarries (represented as K1, K2 and K3) in part of South-west Nigeria using modified questionnaire and interview. The quarries' current maintenance management effectiveness was evaluated with respect to five basic elements of maintenance management. The quarries were rated in accordance with global best practices with credits/ points ranging from 1 to 3. Investigation shows that K1 and K2 had average overall ratings of 1.45 and 1.39 respectively. These scores fell below average performance, which informed their inability to operate at profit and call for urgent improvement decisions in all elements of maintenance management benchmarked. K3 scored 2.48, which indicates that the quarry adopts an effective maintenance management system, but will also need to improve on its preventive maintenance and maintenance scheduling. This paper is therefore an assessment initiative for maintenance and productivity continuous improvement and can be integrated as apart of a decision support system for maintenance management in the quarry industry.
Evaluation of Equipment Maintenance Effectiveness in Selected Typical Granite Quarries in South-West Nigeria
(2018) ABDULRAHMAN, S.O.; OLALEYE, B.M.; SALIU, M.A.
Equipment maintenance performance indices allow quarries to understand the value created by maintenance, in a bid to re- evaluate and revise their maintenance policies and techniques, to justify investment in new trends and techniques for maintenance management. This research has attempted to evaluate and compare three maintenance performance indices I1, I2 and I3 (maintenance index; downtime index; and production index respectively) for the studied quarries computed from their records of operational output and maintenance costs for the period reviewed. The index I1 was determined to be between 10 and 20% as against the global standard of less than 6%; index I2 ranged between 19 and 25% as against the industry norm of less than 1% and index I3 averaged 28.5%, while global standard is between 12 and 14%. These indices are not in conformity with the global best standard, this performance is worrisome and has a negative impact on the viability of the quarry business. It becomes imperative therefore that their maintenance policies be revised and their maintenance strategies overhauled to enhance higher performance that can impact positively on the overall corporate goal of the quarries.
Evaluation of Remedial Option's Efectiveness of Lead Contaminated Site in Bagega Community, Zamfara State , Nigeria
(2017) Alaba O. C.; Abdulraman S. O
The study evaluates the remedial option's effectiveness of lead contaminated site in Bagega community, Zamfara state. Samples of soil and water were collected from residential compounds (BRC), residential garden (BRG), village common area (BVC), processing areas (BPA), farmland areas (BFA), wells (BWE), boreholes (BBH) and ponds (BPO)water at the same locations before and after remediation using standard procedures of ASTM D6907 and APHA respectively. The concentrations of lead metal in soil and water samples before and after remediation were determined using Atomic Absorption Spectrophotometer (AAS) in accordance with ASTM D 3559 and ASTM D1976 standard methods. The results revealed that soil samples recorded the highest lead concentration reduction of 96.1% in BRG while the least lead concentration reduction of 51.7% was recorded in BFA after remediation. Water samples recorded least lead concentration reduction of 21.0 % in BBH and highest lead concentration reduction of 70.8% in BPO after remediation. On the health risk analyses, BPA/01, 07 and 11; BFA/04, 07 and 08 posed health risk to the people while BPO/02, 06 and 09 posed no health risk to the people after remediation. The study therefore concluded that remediation was completely effective at BRC, BRG and BVC but it was not completely effective at BPA and BFA.
Flame Jet Burner Application and Performance characteristics in Cutting Miya Granite for Dimension Stone
(2014) Idris Ibrahim Ozigis; Abdulrahman S. Ottan
This work examines the application and performance characteristics of FA300A flame jet burner in cutting Miya granite for dimension stone. The application procedures involves preparation to start flame jet cutting by removal of overburden, boulders and other impurities using bulldozer, payloader and compressed air, respectively. Furthermore, ignition of the flame jet burner involves combustion of diesel gas at appropriate time using acetylene gas and oxygen as well as compressed air. The flame jet cutting operation utilized continuous heating of rock to its spallation until flakes are formed from the surface of granite kerf. Performance test of flame jet burner in cutting Miya granite for dimension stone were conducted with reference to actual cutting speed, heat release rate, penetration rate and productivity. The heat input of the flame jet burner was determined to be 483.1 kW resulting in heat release rate per unit internal cross sectional area of the burner as 680,433.5 kW/m2 while heat release rate per unit volume of flame jet burner was 1, 134, 038 kW/m3. The penetration rate of 0.4 mm/s was obtained when FA300A flame jet burner was applied to cut Miya granite for dimension stone. The flame jet burner had cutting speed of 1.65 m2/hr and productivity of 16.6 kg/m2.s in cutting Miya granite for dimension stone. Also highlighted were operating parameters of the flame jet burner that must be kept in mind for its improved adaptation in Nigerian mineral extractive industry.
Fostering the Sustainability of Artisanal and Small-Scale Mining (ASM) of Barite in Nasarawa State, Nigeria
(2021) Itohan Otoijamun; Moses Kigozi; Sikiru Ottan Abdulraman; Adelana Rasak Adetunji; Azikiwe Peter Onwualu
The exploration and mining of Nigerian barite are primarily by artisanal and small-scale miners (ASM) whose operations are characterized by poor productivity. As a result, the quantity and quality of barites produced do not satisfy the nation’s oil sector demands and other industries that require the mineral. This situation leads to massive importation of the mineral with negative impact on the country’s drive toward increasing the contribution of solid minerals to the gross domestic product (GDP). This study reviews the existing policies and government interventions on ASM of Nigerian barite; evaluates the operations of ASM through a survey of mines in Nasarawa state, Nigeria; identifies factors that affect sustainability of the sector and proffers solutions to foster sustainability of ASM of barite in the region. The study adopted the 4Is optimization technique (Information gathering, Interpretation, Implication, and Implementation) through personal interactions with the stakeholders at the barite mining sites, and government agencies, regarding policies and interventions specific to ASM of barite. Challenges identified include: weak implementation and enforcement of mining laws; inadequate support from government and development partners; poor access to mining equipment and technology; poor infrastructure (access road, water, electricity); poor pricing of products (marketing challenges); poor remuneration of mine workers; poor mining skills; inadequate formal education; limited awareness on environmental health and safety hazards; fragility and conflict; insufficient information and data on mines and miners; security issues; lack of access to finance; lack of formalization of operations and poor legal framework for operations. The strategies suggested for fostering the sustainability of ASM of barites include: enhanced policy and legislation formulation and implementation, strengthening of institutions, formalization of ASM operations, training of miners, awareness campaign, improvement in environmental and safety of operations, empowerment and support by government and development partners for individual miners and processors and organized groups within the sector (such as Miners Association of Nigeria, Association of Miner and Processors of Barite, AMAPOB). Implementation of these strategies will lead to sustainable operations of the sector and hence improved rural livelihoods, stimulation of entrepreneurship in an environmentally responsible manner, and improvement in the contribution of the mineral sector to the nation’s gross domestic product (GDP), and hence national development.
IMPACTS OF COVID-19 PANDEMIC ON NIGERIA’S ECONOMY: EFFECTIVE FOUNDRY TECHNOLOGY AS A SUSTAINABLE SOLUTION
(2022) Yusuf Lanre SHUAIB-BABATA, Olanrewaju Yusuf BUSARI; Rasheedat Modupe MAHAMOOD, Salihu Swarnu YARU; Lawal Babatunde ABDULQADIR, Ibrahim Owolabi AMBALI; Kabiru Suleiman AJAO, Sikiru Ottan ABDULRAMAN
This study considered the effect of the Covid-19 pandemic on the economy of Nigeria and investigated the effective application of foundry technology to proffer a sustainable solution to the problem. Domestication of production of motorcycle components, being a significant means of transportation that is required for the development of any society was considered. Aluminium scraps from a waste dump and Belle and Oyun natural moulding sands in Kwara State, Nigeria, which have been previously recommended for non-ferrous casting in previous studies were considered and used for casting of motorcycle/tricycle parts (centre stand and brake pedal) using AFS guidelines. The scraps’ chemical compositions were analysed. Thereafter, some mechanical properties with the microstructure of the aluminium casts and that of commercially obtained imported types were examined using appropriate ASTM standards. Cast aluminium alloy produced using scrap had no casting defects and had some mechanical properties comparable to those available on the markets (imported). Thus, effective usage of naturally available moulding sands in Nigeria for foundry applications would help to proffer sustainable solutions to the nation’s economic problem as a result of the adverse effects of the Covid-19 pandemic.
Important Technical Considerations in the Development of Bankable Documents for Quarry Operations
(2017) S. O. Abdulraman
Today's quarry operations are characterised by high capital expenditure, low product priceand high operating costs including energy costs (diesel cost). Consequently, when deciding on quarry investment, there is little room for inefficiency in quarry design and production scheduling and consequently, in the estimates of the quarry project's value. A doubtful and badly implemented quarry evaluation process could wrongly classify a non-profitable venture as being profitable with appreciable probability, and vice versa. And the consequence of a badly implemented quarry investment evaluation process has economic implications to both the promoters and stake holders of the project with financial institution (BOI') inclusive. Many quarries financed by Nigerian banks record poor performances due to the technical flaws inherent in the So-called Bankable Feasibility study reports submitted during the loan Application process. This paper suggests the need to engage competent hands (Mining Engineers /Mining Consultants) to carry out technical due diligence on every mining project funding or loan applications to guarantee effective and efficient funding of mining projects and justify BOl’s contribution to nation's minerals industry. Also, engage team of engineers to monitor the performance of the quarry throughout the loan period. So as to ensure that the quarry run optimally to guarantee quick pay back and return on investment.
Influence of thermal ageing on the microstructural and mechanical characteristics of banana stem particles reinforced aluminium-alloy matrix composites
(2024) Sefiu Adekunle Bello; Abdul Ganiyu Funsho Alabi; Suleiman Danjuman Daudu; Stephen Durowaye; Mohammed Kayode Adebayo; Luqman Babatunde Eleburuike; Sikiru Ottan Abdulraman; Shuaib Ajibola Mohammed
The influence of thermal ageing on the microstructural and mechanical characteristics of banana stem particles (BSp) reinforced aluminium-alloy matrix composites was investigated. Sand casting was used to produce the composites, comprising aluminium alloy matrix reinforced with BSp of varying weight ratio of 0 wt. %, 1 wt. %, 3 wt. %, 4 wt. %, 5 wt. % and 6 wt. % were thoroughly mixed. Test samples for mechanical characterisation were prepared from the sand cast (6 mm diameter by 125 mm rods for tensile test). Thermal ageing was done for 2 hours (hrs) at 350 0C. The composites were evaluated for tensile, modulus of elasticity, hardness, and microstructural characteristics. The thermally aged samples demonstrated greater tensile strength and toughness as the concentration of BSp increased up to 5 wt. % in the composite in comparison with the as-cast samples. The greatest characteristics were demonstrated at 5 wt. % BSp concentration. Lower hardness was demonstrated by the as-cast samples in comparison with the aged-hardened samples. There was 5 wt. % BSp concentration in the alloy enhanced thermal ageing. These indicate that greater mechanical characteristics of the composites can be obtained by thermal ageing.
Investigation of Some Physical and Strength Properties of Clay and Weathered Bedrock for Production of Hydra Form Bricks
(2010) S. O. Abdulrahaman; B.M. Olaleye; M. A. Saliu
Clay and weathered bedrock samples at Ilorin, Kwara State, Nigeria have been investigated; as alternative earth materials for the production of hydraform bricks. Varying mixes of clay and weathered bedrock samples were evaluated and their physical and chemical properties determined. The compressive strength of the bricks made from different mixes were determined using Hydraform Block Tester. The result of the investigation showed that a 50:50 mix ratio of clay and weathered bedrock samples gave hydraform bricks of highest strength averaging 4.4 MPa which makes it better and stronger hydraform blocks than the ones produced from laterite which is 2.90 MPa. The mix ratio also has a medium absorption rate of 6.25% which falls within ASTM standard and which is quite adequate for construction works applications.
Investigation of the Effect of Weathering of Selected Charnockite Rocks in Nigeria on Its Engineering Properties
(2022) Abdulraman SO; Musa VI; Saliu MA; Abdulkadir IA
The effect of alteration in the petrographic characteristics of charnockite on its strength, its engineering properties and transformations of the specific gravity which took place during weathering has been examined in this study. This study characterized selected samples of un-weathered and weathered charnockite rocks of Ijare, Ondo State, Nigeria. The physical properties determined were specific gravity, density, porosity, water content and water absorption while the mechanical properties investigated include the point load strength index. Results from the analysis carried out reveal: the point load index of 5.74Mpa and 3.72Mpa for unweathered and weathered samples; average uniaxial compressive strength of 136.90Mpa and 65.50Mpa for unweathered and weathered samples; slake durability of 98.80% and 97.80% for unweathered and weathered sample; Schmidt rebound value of 49Mpa and 45Mpa for both the unweathered and weathered samples respectively. The rock samples were also subjected to petrographical analysis whose result shows that weathering increases some investigated physical properties like porosity, water content and water absorption of the rock while decreasing the specific gravity and density. The result of the tests shows the bulk and dry densities increase for both the weathered and unweathered samples; increased degree of weathering equally results in a major reduction in the strength of the charnockite rock which is directly associated with changes in mineralogy and associated porosity. The point load strength, uniaxial compressive strength test and rebound hardness result values decreases because of weathering. Weathering processes also affected the physical properties of rock, mineralogy, chemical composition as well as the mechanical properties of the rock thereby reducing the strength and mechanical behavior of the rock materials.

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