Analisis coal losses pada kegiatan penambangan di Pit Inul Middle Panel 3 PT Kaltim Prima Coal

Coal Losses merupakan proses hilangnya batubara yang terjadi pada saat proses penambangan berlangsung sampai pada saat pengiriman batubara ke tujuan. Proses penambangan batubara seperti clean up roof batubara, proses pemuatan batubara, serta saat pengangkutan batubara menuju stockpile berpotensi menimbulkan coal losses. PT Kalimantan Prima Coal menetapkan coal recovery criteria sebesar 98,5%, lebih ketat dari yang ditetapkan Kementerian Energi dan Sumber Daya Mineral (ESDM) sebesar 90%. Penelitian ini bertujuan untuk menghitung coal losses pada proses clean up batubara, pemuatan batubara di loading point, dan pengangkutan batubara; mengetahui faktor-faktor yang menyebabkan terjadinya coal losses; dan memberi rekomendasi upaya penanganan coal losses.Penelitian dilakukan di Pit Inul Middle Panel 3 pada PT KPC bulan Mei dan Juni 2019. Ada lima seam batubara yang diamati, yaitu seam K17LR, K13, K12, K9 dan K4. PT KPC menggunakan survey yang dibandingkan dengan truck count untuk menghitung coal recovery. Total coal losses yang didapat dari setiap seam dibagi menjadi tiga proses penambangan batubara, yaitu coal losses pada saat clean up roof batubara, di loading point, dan saat hauling.Coal Losses yang didapatkan pada seam K17LR bulan Mei dan Juni 2019 sebesar 4,49% dan 3,93%; seam K13 bulan Mei dan Juni 2019 sebesar 2,83% dan 1,47%; seam K12 bulan Mei dan Juni 2019 sebesar 3,57% dan 2,71%; seam K9 bulan Mei dan Juni 2019 sebesar 4,24% dan 4,15%; seam K4 bulan Mei dan Juni 2019 sebesar 4,3% dan 1,11%. Coal losses yang terjadi masih di atas dari kriteria yang diberikan oleh ESDM sehingga masih memenuhi batas kriteria. Persentase coal losses terbesar terjadi di loading point sehingga dilakukan simulasi pengurangan coal losses di loading point. Total losses 19.43% pada Bulan Mei and dan 13.38% pada Bulan Juni berhasil diturunkan menjadi 9,44% and 6,98%. Kata-kata kunci : batubara, recovery, clean up, loading point, hauling

Water structure and dynamics in the hydration layer of a type III anti-freeze protein

The tetrahedral structure of hydration water (S) and its reorientation decay time (τ) correlates negatively for selected amino-acids in the vicinity of the ice binding site (left and right panels) of the antifreeze protein, but positively for the ice binding site central amino-acid (middle panel).

Mesoporous layered hexagonal platelets of Co3O4 nanoparticles with (111) facets for battery applications: high performance and ultra-high rate capability

High performance battery behaviour (left panel) of mesoporous layered hexagonal platelets (middle panel) composed of highly crystalline Co3O4 nanoparticles with (111) facets (right panel) in an aqueous electrolyte of 2 M KOH.

Vom Ambo zum Retabel – Das Klosterneuburger Goldschmiedewerk von Nikolaus von Verdun

The only signed work by Nicholas of Verdun, the metalwork which adorned the former ambo in the Klosterneuburg Monastery, was integrated into a foldable altarpiece around 1330 and thus transformed into a new medium. Besides being reframed, it was combined with new monumental paintings on the rear side of the triptych. It was not only handled differently and defined spatially in completely different terms, but the precious enamel- and metalwork could be hidden from sight by closing the wings. The added plates of metalwork at the center of the middle panel break up the hieratical and Eucharistic program of the original work, focusing the program on devotional affects. The metalwork and paintings form a sophisticated iconic reference system, pointing to the provost Stephan of Sierndorf, who had ordered the reframing. His painted figure, kneeling before the crucified Christ, reveals itself not only as the image of the donor, but also as the ideal beholder of the work or a further exemplum of perfect piety.

Women and Space: The Flowering of Desire

Thomas pynchon's oedipa maas sees in the Varo triptych echoes of her own Rapunzel-like state, her world a tower from which Pierce Inverariety has ineffectually tried to rescue her. Pynchon does not comment on the other two panels of the triptych. In the first, the young women (more slender than frail) file away on bicycles from their conventlike towers – out for exercise or a trip to town; in the last, one of the maidens departs with her knight of deliverance. Nor does Pynchon observe that in the middle panel the young women, embroidering the tapestry of the world in their communal solitude, create the world. In which panel, one might ask, are the young women most free?The work of Remedios Varo is filled with women in towers; spinning, weaving, writing poetry, composing music – creating the world. All of the women are the same woman. She frightens Pynchon. “Such a captive maiden,” he writes, “soon realizes that her tower, its height and architecture, are like her ego only incidental: that what really keeps her where she is is magic, anonymous and malignant.”