This paper presents an automated system for optimizing earthmoving operations. The proposed system can assist earthmoving contractors, during bid preparation stage, in estimating the time and cost required in order to accomplish the task at hand. It also provides a methodology for recommending the most suitable equipment fleet that satisfies the job requirements and the stated objectives of contractors. The system consists of four components: 1) simulation module; 2) equipment cost application (ECA); 3) equipment database application (EDA); 4) reporting module. The paper provides a brief description of the system and focuses primarily on the design of the simulation module utilizing object-oriented simulation (OOS). A numerical example is presented to demonstrate the use of the developed system and illustrate its capabilities.