Abstract. Based on the conditions, the production target planned by the company was not reached. This can be caused by the factors of obstacles as well as the material loss factors that occur during the processing and distribution of materials. Therefore it is necessary to conduct a study of the crushing plant cycle unit in order to evaluate the performance of the tools used so that the company's production targets can be achieved. The research methodology used is by collecting data directly in the field and taking secondary data related to the processing of research data needed from various related sources. For data processing is done by calculating the efficiency of the tool work, the production of each tool, the reduction ratio, and the number of material losses that occur during the processing based on belt cut test data. Based on the results of research and data processing, it is known that the highest average obstacle time is at the secondary crushing I stage 89,03 minutes/day (standby) and at the primary crushing stage 9,72 minutes/day (repair). For the condition or condition of each tool and the effectiveness of its use it is known that the highest EU value is at the primary crushing stage 76,99%, the highest AI value at the secondary crushing I stage 97,76%, the highest PA is 98,25% at the secondary crushing I stage and highest UA at 78,89% at the primary crushing stage. For the results of the calculation of production based on the belt cut test it is known that the primary crushing production is 105,45 tph, secondary crushing I is 150 tph, secondary crushing II is 49,54 tph, and sizing is 154,21 tph. The highest reduction ratio value is known as primary jaw crusher of 2.49 and categorized as medium RR.Not achieving the production target set by the company one of the factors is due to the highest losses of materials at primary crushing stage 0,45 tph or 0,42% of the number of incoming feeds.Keywords: crushing plant, production, losses materials, efficiency, reduction ratioAbstrak. Berdasarkan kondisi di lapangan, target produksi yang direncanakan oleh perusahaan tidak tercapai. Hal ini bisa disebabkan adanya faktor hambatan serta faktor losses material yang terjadi pada saat proses pengolahan maupun saat pendistribusian material. Oleh karena itu perlu dilakukan suatu penelitian terhadap siklus unit crushing plant demi mengevaluasi kinerja alat yang digunakan agar target produksi perusahaan dapat tercapai. Adapun metodologi penelitian yang digunakan yaitu dengan cara pengambilan data secara langsung di lapangan maupun pengambilan data sekunder yang terkait dengan pengolahan data penelitian yang dibutuhkan dari berbagai sumber terkait. Untuk pengolahan data dilakukan dengan cara memperhitungkan parameter availability dan efisiensi kerja alat, produksi masing-masing alat, reduction ratio, serta jumlah losses materials yang terjadi pada saat proses pengolahan berdasarkan data uji belt cut. Berdasarkan hasil penelitian dan pengolahan data, diketahui rata-rata waktu hambatan tertinggi yaitu pada tahap secondary crushing I sebesar 89,03 menit/hari (standby) dan pada tahap primary crushing sebesar 9,72 menit/hari (repair). Untuk keadaan atau kondisi masing-masing alat serta efektivitas penggunaannya diketahui bahwa nilai E.U tertinggi yaitu pada tahap primary crushing sebesar 76,99%, nilai A.I tertinggi yaitu pada tahap secondary crushing I sebesar 97,76%, P.A tertinggi sebesar 98,25% pada secondary crushing I serta U.A tertinggi sebesar 78,89% pada primary crushing. Untuk hasil perhitungan produksi uji belt cut diketahui bahwa produksi primary crushing sebesar 105,45 tph, secondary crushing I sebesar 150 tph, secondary crushing II sebesar 49,54 tph, dan sizing sebesar 154,21 tph. Untuk nilai reduction ratio tertinggi diketahui yaitu pada alat primary jaw crusher sebesar 2,49 dan dikategorikan dalam kategori RR sedang. Tidak tercapainya target produksi yang ditetapkan oleh perusahaan salah satu faktornya karena adanya losses materials tertinggi yaitu pada tahapan sizing sebesar 0,45 tph atau 0,42% dari jumlah feed yang masuk.Kata Kunci: crushing plant, production, losses materials, efficiency, reduction ratio