This technical paper presents a comprehensive analysis of a pilot trial and full-scale sampling conducted at a manganese beneficiation plant. This development in manganese beneficiation allows for improved recovery of manganese, an element essential for steel production and battery manufacture. The trial aimed to compare the performance and efficiency of two pilot-scale REFLUX Classifiers (RC300's) in recovering manganese sand (~P100 1180 um). The existing Beneficiation Plant consists of five parallel full scale REFLUX Classifiers (RC2000s), each with lamella plates installed at 6 mm spacing. Operating data suggested the efficiency of separation is reduced for finer feed particles passing 300 um, owing to the broad feed particle size distribution. Narrower spacing results in increased shear induced lift force between the lamella plates for enhanced gangue rejection as well as increased effective settling area for improved recovery of fine heavy particles (Galvin et al, 2020). The pilot trials aimed to compare the difference in performance between 3 mm and 6 mm lamella plate spacing by taking feed directly from the beneficiation plant feed and operating two RC300's in parallel with each other. One RC300 was installed with 6 mm spaced lamella plates and the other was installed with 3 mm spaced lamella plates. Each RC300 was operated with the same operational set points, and the product and rejects streams sampled to determine the differences in separation efficiency. The successful trial indicated that between a 4.7 to 8.8 per cent manganese recovery improvement could be expected by switching to the 3 mm spaced plates. an average absolute recovery improvement of 9 per cent was measured at full scale. This paper discusses the pilot plant experiment set-up, test work methodology, data collection, analysis, and statistical assessments use to compare the performance of 3 mm and 6 mm lamella spacing to make a recommendation about the viability of retrofitting the existing RC2000s with 3 mm spaced plates as well as full scale results following the full retrofit.