High-pressure　grinding　rolls　(HPGR)　technology　is　a　valuable　way　to　improve　the　extraction　efficiency　of　valuable　minerals;　however,　the　excessively　fine　particles　of　the　HPGR　products　affect　the　heap　permeability　and　limit　its　application　in　heap　leaching.　This　study　aims　at　investigating　whether　the　HPGR　products　can　still　be　leached　efficiently　after　agglomeration　to　provide　new　guidance　for　the　application　of　HPGR　in　heap　leaching.　In　this　study,　the　copper　grain　exposure　of　ores　with　different　particle　sizes　was　tested　by　X-ray　microtomography　(XMT),　and　the　microstructure　characteristics　of　the　ore　under　different　crushing　methods　were　analyzed　by　stereomicroscope,　scanning　electron　microscope　(SEM),　and　nuclear　magnetic　resonance　(NMR).　The　column　bioleaching　tests　were　carried　out　on　the　ores　with　different　particle　sizes　and　the　agglomerates　composed　of　fine-grained　ores　from　different　crushing　methods.　XMT,　SEM,　and　NMR　test　results　showed　that　copper　grain　exposure　increases　with　decreasing　particle　size,　and　HPGR　produces　particles　with　more　micro-cracks　and　higher　porosity.　The　column　bioleaching　tests　indicated　that　the　copper　extraction　increased　with　the　decrease　of　particle　size,　but　excessive　fine　particles　affected　the　heap＇s　permeability　in　the　column.　After　66　days　of　column　bioleaching,　the　copper　extractions　of　agglomerates　composed　of　fine-grained　ores　from　HPGR　and　jaw　crusher　were　55.82%　and　44.16%,　respectively,　while　the　copper　extraction　of　20–30　mm　coarse-grained　ores　was　only　28.54%.　These　results　demonstrated　that　the　increased　copper　grain　exposure　caused　by　the　reduced　particle　size　and　the　richer　micro-cracks　and　higher　porosity　of　the　HPGR　products　could　still　significantly　improve　the　leaching　efficiency　of　copper　ore　after　agglomeration.　©　2021　Elsevier　B.V.