Abstract. PT Semen Padang is a company engaged in mining and processing of limestone into cement. Based on Law no. 4 of 2009 states that the mining of limestone is included in non-metallic minerals. Mining location is located in Batu Gadang Village, Lubuk Kilangan Subdistrict, Padang City, West Sumatera Province.The process of loading limestone materials using mechanical equipment 1 unit Komatsu PC 1800 Excavator which has a capacity of 11 LCM bucket as loading equipment by serving 3 units of Komatsu HD 785 Dump Truck which has a capacity of 100 Ton as a hauling vehicle. The lifespan of each device has reached the age limit of use and is quite old, resulting in a decrease in engine performance. This greatly affects the productivity of the tool and requires special care, so the cost of operating the tool will continue to increase.In planning the replacement of mechanical devices, two main factors to note are technical factors and economic factors. Therefore, a technical review of productivity and economic studies assessed from the cost of production and the calculation of Present Worth Cost (PWC) is required. The productivity calculation results obtained by the old loading equipment is 2,781,368.BCM / year / unit and the new loading device is 4,185,982 BCM / year / unit. While the productivity of the old conveyance means 2,758,503 BCM / year / unit and the new conveyance is 3,499,315 BCM / year / unit. For the calculation of Present Worth Cost (PWC) the old loading device is Rp 101,364,165.856.65 / year / unit for new loading equipment is Rp 90,974,622,997.56 / year / unit, and the old conveyance is Rp 55,951,839,313.77 / year / unit and for new conveyance means Rp 67,672,945,104.14 / year / unit. Based on the study technically and economically for the old loading equipment needs to be replaced because the productivity of the new loading equipment is higher and cheaper while for the old transport equipment it is also recommended to be replaced because in the selection by using the old Production Cost Unit is higher than the new Production Cost Unit, and Production results Cost Old loading equipment unit Rp. 36,443.99 / ton and new loading equipment Rp. 20,918.92 / ton and old Production Cost Unit Rp. 20,283.39 / ton and new transportation equipment Rp. 19,338.91 / ton, then for loading equipment selection and transport can be done by choosing a new tool because it is more economical.Keywords: Device Life Productivity, Owning Cost, Operating Cost, Present Worth Cost (PWC), Production Cost Unit Abstrak. PT Semen Padang adalah perusahaan yang bergerak dalam bidang penambangan dan mengolah batu gamping menjadi semen. Berdasarkan Undang-Undang No. 4 tahun 2009 menyatakan bahwa pertambangan batu gamping termasuk dalam bahan galian non logam. Lokasi penambangan terletak di Kelurahan Batu Gadang, Kecamatan Lubuk Kilangan, Kota Padang, Provinsi Sumatera Barat. Proses pemuatan material batu gamping menggunakan alat mekanis 1 unit Excavator Komatsu PC 1800 yang memiliki kapasitas bucket 11 LCM sebagai alat muat (loading) dengan melayani 3 unit Dump Truck Komatsu HD 785 yang mempunyai kapasitas 100 ton sebagai alat pengangkutan (hauling). Umur dari setiap alat tersebut telah mencapai batas umur pemakaian dan tergolong cukup tua, sehingga mengakibatkan menurunnya kinerja mesin. Hal ini sangat mempengaruhi produktivitas alat dan membutuhkan perawatan khusus, sehingga biaya operasi alat tersebut akan terus mengalami kenaikan. Dalam merencanakan penggantian alat-alat mekanis tersebut, dua faktor utama yang perlu diperhatikan adalah faktor teknis dan faktor ekonomis. Oleh karena itu, perlu dilakukan kajian teknis produktivitas dan kajian ekonomis yang dinilai dari biaya produksi dan hasil perhitungan Present Worth Cost (PWC). Hasil perhitungan produktivitas diperoleh alat muat lama adalah 2.781.368.BCM/tahun/unit dan alat muat baru sebesar 4.185.982 BCM/tahun/unit. Sedangkan produkstivitas alat angkut lama adalah 2.758.503 BCM/tahun/unit dan alat angkut baru adalah 3.499.315 BCM/tahun/unit. Untuk perhitungan Present Worth Cost (PWC) alat muat lama adalah Rp 101.364.165.856,65 /tahun/unit untuk alat muat baru adalah Rp 90.974.622.997,56/tahun/unit, serta alat angkut lama adalah Rp 55.951.839.313,77 /tahun/unit dan untuk alat angkut baru adalah Rp 67.672.945.104,14 /tahun/unit. Berdasarkan kajian secara teknis dan ekonomis untuk alat muat lama perlu diganti karena produktvitas alat muat baru lebih tinggi dan lebih murah sedangkan untuk alat angkut lama juga disarankan diganti karena dalam pemilihan dengan menggunakan Production Cost Unit lama lebih tinggi dari Production Cost Unit baru, dan hasil Production Cost Unit alat muat lama Rp 36.443,99/BCM dan alat muat baru Rp 20.918.92/BCM serta Production Cost Unit alat angkut lama Rp 20.283,39/BCM dan alat angkut baru Rp 19.338,91 /BCM, maka untuk pemilihan alat muat dan angkut dapat dilakukan dengan memilih alat yang baru karena lebih ekonomis.Kata Kunci : Umur Alat, Produktivitas, Biaya Operasi, Biaya Kepemilikan, Present Worth Cost (PWC), Production Cost Unit
PT Semen Padang is a company engaged in mining and processing of limestone into cement. Based on Law no. 4 of 2009 states that the mining of limestone is included in non-metallic minerals. Mining location is located in Batu Gadang Village, Lubuk Kilangan Subdistrict, Padang City, West Sumatera Province.The process of loading limestone materials using mechanical equipment 1 unit Komatsu PC 1800 Excavator which has a capacity of 11 LCM bucket as loading equipment by serving 3 units of Komatsu HD 785 Dump Truck which has a capacity of 100 Ton as a hauling vehicle. The lifespan of each device has reached the age limit of use and is quite old, resulting in a decrease in engine performance. This greatly affects the productivity of the tool and requires special care, so the cost of operating the tool will continue to increase.In planning the replacement of mechanical devices, two main factors to note are technical factors and economic factors. Therefore, a technical review of productivity and economic studies assessed from the cost of production and the calculation of Present Worth Cost (PWC) is required. The productivity calculation results obtained by the old loading equipment is 2,781,368.BCM / year / unit and the new loading device is 4,185,982 BCM / year / unit. While the productivity of the old conveyance means 2,758,503 BCM / year / unit and the new conveyance is 3,499,315 BCM / year / unit. For the calculation of Present Worth Cost (PWC) the old loading device is Rp 101,364,165.856.65 / year / unit for new loading equipment is Rp 90,974,622,997.56 / year / unit, and the old conveyance is Rp 55,951,839,313.77 / year / unit and for new conveyance means Rp 67,672,945,104.14 / year / unit. Based on the study technically and economically for the old loading equipment needs to be replaced because the productivity of the new loading equipment is higher and cheaper while for the old transport equipment it is also recommended to be replaced because in the selection by using the old Production Cost Unit is higher than the new Production Cost Unit, and Production results Cost Old loading equipment unit Rp. 36,443.99 / ton and new loading equipment Rp. 20,918.92 / ton and old Production Cost Unit Rp. 20,283.39 / ton and new transportation equipment Rp. 19,338.91 / ton, then for loading equipment selection and transport can be done by choosing a new tool because it is more economical.