Investigation of particles with high crack density produced by HPGR and its effect on the redistribution of the particle size fraction in heaps

The application of comminution technology such as the High-pressure grinding rolls (HPGR), which is able to generate a high density of cracks in the ore particles, is favourable for leaching processes. Extraction of metallic values by the heap leach process, can take place on the particles with partial exposure of mineral grains, if it can provide sufficient surface front for chemical attack by leaching solution. The aim of this study was to assess the benefits of high crack density in the ore particles produced using the HPGR and how it could diminish due to inadequate percolation of the leaching agent. A zinc ore was comminuted using HPGR at three different pressure settings and with a cone crusher for the control experiment. Subsamples from the (+23/-25, +14/-16, +5.25/-6.75 mm) size fractions were characterized and packed into leach reactors. The reactors were stopped from time to time to investigate the progress of crack and micro-crack growth and its effect on metal extraction using the X-ray computed tomography (CT). The results are validated with those obtained using traditional techniques such as SEM and QEMSCAN. Investigation of the leach reactors residue indicated significant changes in the particle size distribution (PSD) of initial feed toward the fine size fraction. The residues from the reactors leaching the material prepared using the HPGR product contained more fine particles than the reactors, which were fed by cone crusher product. These differences were up to 10.3%

Pneumonia caused by Candida krusei and Candida glabrata in a patient with chronic myeloid leukemia receiving imatinib mesylate treatment

In this report we describe a patient suffering from chronic myeloid leukemia (CML), who was treated for 4.5 years with imatinib and developed pneumonia caused by two Candida species, i.e., C. krusei and C. glabrata. The patient was in complete hematologic remission and molecular analyses did not display the presence of TLR2-R752Q, TLR4-D299G and TLR4-T399I polymorphisms that may predispose individuals to fungal infections. This case report indicates that in some patients, as previously observed, the long-term administration of targeted therapy might affect immunity and predispose patients to opportunistic and life-threatening fungal infections