What are the factors that have to be taken into account when chartering self-discharging cement carriers? Practical experience gained during a substantial hydropower dam construction project in Panama provides the answer. Ad Ligthart of Cement Distribution Consultants, who was responsible for the purchase of 260,000t of cement and flyash and the logistics to transport them to the concrete dam site, reports.
Between the end of 2007 and 2011 a large construction project on the Changuinola river on the Caribbean side of Panama, close to Costa Rica, was realised by Changuinola Civil Works, a joint venture between E Pihl & Son and MT Højgaard, the two largest contractors in Denmark. The project consisted of a large concrete dam of 100m high and 600m wide at the top for which about 900,000m3 of concrete were required. From the dam, a tunnel of over 4km was blasted through a hill cutting off a bend of the river and adding another 40m of water pressure above two 105MW turbines in a powerhouse at the end of the tunnel. A mini powerhouse of 10MW was added at the base of the dam to maintain an environmental flow through the river bend which was cut off by the tunnel. The project also consisted of 22km of permanent roads, including four bridges. A description of the project was provided in ICR August 2010 when building work was in full swing.
The construction of the dam was realised in 17 months from December 2009 to April 2011. This meant that between November 2009 and March 2011 a total of 220,000t of cement and fly ash had to be transported to the project. Before the construction of the dam could start, two years of preparations were required. These included the construction of roads to the project, realising an 8000kW power plant, a crushing plant, aggregate and sand mining operations, two ready-mix plants, a huge workshop and two camps for personnel (one of them for expatriates). During this period work on the tunnel, powerhouse and foundation of the dam also took place. About 40,000t of cement and fly ash were imported in Big Bags during this period.