The system dynamics methodology originally developed by J. W. Forrester for modelling and simulation of decision-making processes at enterprises is nowadays applied to many different fields, such as transportation, ecology, healthcare, biology, economics, etc. Instead of traditional flow diagrams and equations in the DYNAMO language, a block-textual specification is proposed. This form is considered to be more convenient for engineers familiar with control engineering. A model of transportation of kimberlite ore created in the modelling and simulation environment ISMA is given in order to illustrate the approach.