Add spaces: Speciallicenseswereneededforvariousoperations,sothattheremainingonesfounditverydifficulttooperate.

Answer: Special licenses were needed for various operations, so that the remaining ones found it very difficult to operate.

Add spaces: Saturday17February,201861944880requestssinceTuesday16December,2003

Answer: Saturday 17 February, 2018 61944880 requests since Tuesday 16 December, 2003

Add spaces: Toavoidreliefwithlayersandcoatings,mountingmayhelptoimprovetheresult.

Answer:
To avoid relief with layers and coatings, mounting may help to improve the result.