MOTIVECTION : Journal of Mechanical, Electrical and Industrial Engineering

Geometric Redesign and Cut-and-Fill Volume Estimation of a Non-Compliant Mine Haul Road at Pit Banko Tengah A, South Sumatra

Dwi Lestari — 2026-07-26

Mine haul roads must satisfy geometric standards to ensure safe and reliable heavy-equipment mobilization. This study evaluated the inactive Tesla haul road at Pit Banko Tengah A, South Sumatra, for reactivation using Komatsu HD-785 rigid dump trucks. Existing road geometry was assessed against operational standards, followed by 3D spatial redesign and cut-and-fill volume estimation in hilly terrain. The results showed that several straight segments require widening, with the largest correction reaching 7.93 m to meet the 24 m standard. Segment 5 also requires curve widening and superelevation correction, with actual superelevation of 0.064 m compared with the 1.223 m design requirement. Road grades remained within the 8% maximum limit. The redesign produced an excavation-dominant earthwork profile, consisting of 203.92 BCM of cut and 9.79 BCM of fill. These findings provide a practical basis for planning haul-road reactivation while aligning geometric compliance with earthwork requirements.

Comparative Exhaust-Gas Characteristics of Sugarcane Bagasse and Pineapple Waste Bioethanol Blends in a Fuel-Injected Motorcycle under a Common HHO-System Configuration

Calvin M. P. Sinaga — 2026-07-27

Agricultural waste-derived bioethanol offers a renewable gasoline-blending option for spark-ignition engines. This study compared sugarcane bagasse- and pineapple waste-derived bioethanol blends in a fuel-injected Honda BeAT motorcycle operated under a common HHO-system configuration. Five fuel formulations—E0, E5-SC, E10-SC, E5-PW, and E10-PW—were tested at 1500, 4000, and 7000 rpm. CO, HC, CO₂, and O₂ were measured using a four-gas analyzer, while λ and AFR were reported by the analyzer. Results are presented as means from three replicate runs. E10-SC recorded the lowest mean CO concentration at 4000 rpm and the lowest mean HC concentration at 7000 rpm, whereas E10-PW recorded the lowest mean CO concentration at 7000 rpm. The formulation rankings varied with engine speed and measured parameter. Because HHO was not tested independently, its specific contribution could not be determined.

Task-Level Mapping of Electrical and Oil-Handling Risks during Transformer Oil Purification: A Job Safety Analysis at PT PLN Batam

Nanda Putri Utami — 2026-07-27

Transformer oil purification combines electrical isolation, auxiliary power, pressurized oil transfer, dielectric testing, and recommissioning, creating interconnected electrical and oil-handling hazards. This study mapped task-level risks and specified stage-specific controls for the purification workflow at PT PLN Batam using Job Safety Analysis. A single-site case study examined ten stages through observation, 30 maintenance interviews, and operational safety-document review. Hazards were classified retrospectively using a 5 × 5 likelihood–severity matrix. Seven stages were rated high risk and three medium risk. Purification-unit connection received the highest score (15) because electrical and oil-transfer interfaces converge at this stage. Proposed controls emphasize verified isolation, lockout/tagout, competent authorization, pressure-rated connections, containment, spill readiness, and independent restoration checks. Under assumed full implementation and verification, the profile is projected to shift to seven medium-risk and three low-risk stages. The study provides a transparent task-level control map while distinguishing projected residual risk from measured outcomes.