An experimental investigation into the borehole drilling and strata characteristics

Measurement while drilling is an important part of the intelligent development of coal mines. The main purpose of this paper is to comprehensively analyze the response characteristics of borehole drilling parameters and find a better method to predict rock mechanical properties based on drilling parameters. Firstly, six concrete blocks and multiple specimens were prepared with different material ratios. Next, the concrete specimens were tested for mechanical properties in the laboratory. Meanwhile, the displacement, rotation speed, torque, and sound pressure level (SPL) were observed during the drilling of the concrete blocks. Finally, the response characteristics of drilling parameters such as rotation speed, rate of penetration (ROP), torque, and SPL were analyzed. Besides, multiple prediction models of rock mechanical parameters were obtained by data analysis. The research results indicate that the drilling process can be classified into the initial stage of drilling (fast speed) and the steady stage of drilling (slow speed). The torque work ratio accounts for more than 99%, which increases with the increase in rock strength. The penetration depth per revolution and torque work ratio are significantly related to rock uniaxial compressive strength, Brazilian tensile strength, cohesion, and elastic modulus. The ROP is the best choice for estimating rock mechanical parameters. This research provides an important reference for laboratory rock mechanics parameter testing and geological features detection based on drilling parameters.

FEASIBILITY ASSESSMENT FOR DRILLING AND REHABILITATION OF WATER SUPPLY BOREHOLE SCHEME AT AWARO CAMPUS, AMBO UNIVERSITY

Groundwater is a crucial element to water systems and supplies of small to large communities worldwide. This study is based on review of relevant previous studies, primary data collected through comprehensive field survey in the project area Ambo University Institute of Technology, secondary data gathered from various offices at regional levels, and consultations with project affected communities, Administrators, key stakeholders, NGOs and relevant experts. The cause of failure of the bore well is assessed and parts of the scheme component that need maintenance, repair and replacement in addition to water quality condition is estimated in monetary value to undertake systematic cost benefit analysis to decide whether to drill new boreholes or rehabilitate existing sites. Document analysis, interviewing, group discussion and reconnaissance survey/observational approach is used to gather data and information. The Costs and benefits of borehole drilling and rehabilitation analysis was estimated. The total cost was estimated at US$ 31,282 in the borehole drilling and US$ 10,167 in the borehole rehabilitation. The total economic benefit was estimated to be US$ 140,385 for 20 years in the borehole drilling and US$ 28,513 for 10 years in the borehole rehabilitation. The cost-benefit ratio was 4.5 for borehole drilling and 2.8 for borehole rehabilitation. The output of this analysis revealed that constructing the new borehole is better than rehabilitating that would save the institute from wastage of time and capital planned for rehabilitation in addition to sustainability and reliability function of the borehole for long period of time

Mechanism and Procedure of Repeated Borehole Drilling Using Wall Protection and a Soft Structure to Prevent Rockburst: A Case Study

With the increasing mining depth of coal mines, the occurrence of rockburst, especially in mine roadways, is becoming critical as a severe dynamic disaster. This paper explores the stability control of deep mine roadways and solves the contradiction between the support and pressure relief of roadways by studying the use of an internal steel pipe for wall protection and a soft structure for energy absorption during repeated borehole drilling. Numerical simulations are performed to examine the effects of active support technology on the support structure during repeated drilling. Internal steel pipes can effectively prevent the support structure from being damaged. When the soft structure cracks, the energy transmitted from the rockburst to the roadway is significantly reduced. According to the deformation and failure characteristics of the surrounding rock of the 21170 roadway, the combination of anchor active support, hydraulic lifting shed support, and soft structure energy absorption is proposed. An engineering case study shows that the support method can effectively maintain the stability of the surrounding rock and ensure the safe mining of the working face. The proposed control method can provide reference for the prevention and control of rockburst in mine roadways under similar geological conditions.

Striving for Borehole Drilling Professionalism in Africa: A Review of a 16-Year Initiative through the Rural Water Supply Network from 2004 to 2020

Drilled boreholes are vital to achieving universal, safe drinking water and meeting Sustainable Development Goal (SDG) 6.1, particularly in Africa. Poor quality siting, borehole design, drilling and completion lead to premature failure of the water supply. From 2004 to 2020, a multi-stakeholder initiative through the Rural Water Supply Network (RWSN) has endeavored to raise the professionalism of borehole drilling and its management in Africa. The initiative comprised in-country and desk studies, training, and the development of guidelines, manuals, training materials, short animated films for advocacy as well as using blogs, webinars and online communities of practice to share experiences. The initiative was funded to approximately USD 750,000 in total. Funding was fragmented throughout, but the initial support by the World Bank Water and Sanitation Programme Africa (WSP-AF), consistent leadership and subsequent partnerships between Skat Foundation, United Nations Children’s Fund (UNICEF), WaterAid UK and others enabled progression on the topic, as well as innovation and opportunities to be harnessed. The initiative has raised the profile of drilling professionalism, provided a wealth of materials and inspired others to take action. Thousands of stakeholders have improved their knowledge. Academic research on the topic has also increased and capacity strengthening of groundwater management and professional drilling is now an action area for the African Ministers Council on Water (AMCOW). UNICEF and WaterAid are among the organizations that have made changes to procurement and project management as a result of the initiative. Despite a growing recognition of the importance of drilling professionalism, reliable, long-term investment in in-country training and professional development, and addressing challenges in the institutional environment remains inadequate. Despite the importance of water well drilling, and commitments to SDG 6.1, capacity strengthening in this area remains a marginal issue for national and international political leadership, and arguably for international funding agencies.

Challenges of private provision of potable water in Obio/Akpor Local Government Area and its Socio-economic implications

Water is a basic and necessary requirement for the existence of animals and plants, yet it is limited in supply in several parts of the world. Surges in human population and demand for water for different purposes such as agricultural, domestic and industrial usages are the major factors leading to water scarcity. Nigeria and the study area are blessed with abundant water resources including surface and groundwater, yet there is a palpable lack of adequate and safe potable water. Consequently, the populace resorts to private sources of water supply which has its negative externalities even though the effort seems laudable. Based on the above, the study examined the proliferation of private water supply, its challenges and socio-economic implications in Obio /Akpor local government area. The study adopted a cross-sectional survey, and data were collected with the use of both closed and open-ended questionnaire. It also involved the collection of the private borehole points with the use of a handheld global positioning system (GPS). Data were analyzed using the descriptive method of analysis and data presented in charts and tables. The result of the study showed that there were no specific distances maintained between borehole points, a good number of borehole locations were clustered in some parts of the study area. Also, distances between soakaway pits and borehole points were inadequate in some communities. Based on the prevalent minimum wage in the study area, both households that operate boreholes and those that buy water spent more. Some of the socio-economic implications of private provision of water supply include too much spending on water, creation of livelihoods for water vendors and vulnerability to waterborne disease such as typhoid since there is no minimum standard for borehole drilling and distance in the study area. The study recommended that the government should develop a private borehole drilling standard that would include the minimum distance that must be maintained between two boreholes on vertical and horizontal lines. Also, the activities of the private water vendors should be regulated, and operating license obtained before operating commercial boreholes. The study concluded thus, there should be a synergy between the private and public sector to ensure safe and affordable water supply since their activities cannot be undermined.

Efficacy of Geophysical Techniques for Groundwater Exploration in the Volta Basin, Northern Region of Ghana

Groundwater, traditionally extracted from hand-dug wells and boreholes is the main drinking water source in the Northern Region of Ghana. Many boreholes have been constructed in the region to increase accessibility to potable water mainly as part of rural water supply projects where borehole siting has to be relatively cheaper. These projects have resulted in low success rates of borehole drilling because of the application of inefficient and simple geophysical techniques supposed to be cheaper. Field surveys were conducted with the Electrical Resistivity Imaging (ERI) technique, Electrokinetic System (EKS) sounding technique and Radon (222Rn) technique with the objectives of determining the best geophysical methods for borehole siting and its efficiency in the Volta Basin (VB) in the Northern Region of Ghana. The surveys were conducted at stations of existing dry and positive boreholes. Results show that the three geophysical techniques are efficient to identify groundwater accumulation zones. The ERI, EKS and 222Rn are efficient to identify discontinuities, calculate hydraulic conductivity of discontinuities and identify areas of water circulation respectively. It is recommended that the ERI be used to obtain discontinuities and weak zones for drilling on rural water supply projects in the VB. The EKS and 222Rn should be conducted to evaluate these features when high yield boreholes are required. Keywords: Geophysical Techniques, Volta Basin, Borehole Drilling, Success Rates