Improving the Productivity of Basalt Rock Crusher through Workflow Process Redesign and Additional Crushing Components: A Case Study of the Terex TC1000 Crusher at PT Putra Perkasa Abadi Jobsite MAC

Abstract

Background: The crusher is the core of the basalt quarrying business at the PT Putra Perkasa Abadi (PPA) MAC jobsite. From April to June 2025, the productivity of the Terex TC1000 crusher averaged only 34.83 Lcm/h (87% of the 40 Lcm/h target), causing production shortfalls and a revenue gap against plan of –IDR 95.52 million. Methods: This applied study used an eight-step Plan-Do-Check-Act (PDCA) cycle and Quality Control Project (QCP) methodology to identify the root causes of low productivity and evaluate the effectiveness of a crushing-circuit modification, through Pareto analysis of downtime from January to June 2025 and a cause-and-effect (fishbone) diagram across the Man, Material, Machine, and Method categories. Results: Pareto analysis identified the MC Cone as the largest downtime contributor (124 hours; 36.6%), while the fishbone diagram revealed that most primary jaw product measured 20–30 cm, exceeding the ideal cone feed size of 10–15 cm, with an inadequate workflow design and component composition as the dominant root cause. The selected solution—a workflow redesign combined with a secondary jaw crusher, two vibrating screens, a second surge bin, a PLFC sand maker, and 11 additional conveyors (14 in total), with an investment of IDR 7.46 billion—raised average productivity in October–December 2025 to 57.44 Lcm/h (144%;

+64.9%), turned the revenue gap positive at IDR 457.05 million, and increased the crusher rental rate from USD 190 to USD 283, so that the Plant Department's average rental revenue rose 136.6% to IDR 1,645.46 million per month. Conclusion: Staged size reduction with closed-circuit screening effectively improved productivity, product quality (five fractions for LPA/LPB/LPC blending), and the financial performance of the basalt crusher, with an indicative revenue-based payback of about 7.9 months.