loading DATA with sql loader

Hi all

I want ot load 600,000 records on table like

SQL> desc research.CLOSEDCASE_TEMP
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 CASENUMBER                                         CHAR(15)

with one flat file like this

318072018000024
318072018000025
318072018000026
318072018000029
318072018000030
318072018000031
318072018000034
318072018000036
318072018000040
318072018000041
318072018000042
318072018000047

so i was thinking to use the next commands and control file

sqlldr username/password@server control=loader.ctl

the loader.ctl file would have

load data
infile *
 into table RESEARCH.CLOSEDCASE_TEMP
 (   casenumber(01:15) char(15)
  )
begindata
BEGINDATA
11111AAAAAAAAAA
22222BBBBBBBBBBB

Regards

Jesus