This paper presents an approach for modeling the supply chain in the semi-integrated steel industry. A case study is taken from a Colombian company. The production of this company is based on waste management: recycled iron and steel scrap. The supply chain is modeled using linear programming. The model looks for the minimization of total logistics (production and distribution) costs considering intermediate and final products. Input data and constraints concerning raw material suppliers, manufacturing plants, distribution centers and local sales and imports are considered. The model is intended to be used as a support tool for decision-making at a strategic and tactical decision levels. The strength of this contribution is that it gives some insights about the situation and the structure of the semi-steel industry (i.e., based on recycled steel waste) in Colombia by modeling the different costs for production and transportation.