Egyptian gold miner Centamin has maintained its gold guidance for the year despite challenges during the first quarter from lower grades and poor mining fleet availability underground.Total gold production for the quarter was 74,241 ounces, a 14% decrease on the corresponding quarter in 2013 and 19% lower than the fourth quarter of 2013. The FTSE 250 company said that although gold production was affected by a temporary reduction in the underground average grade, it generated record levels of material movement from the underground mine and process plant throughput.Centamin said all areas of its operations "provided a solid foundation for the year ahead", with production guidance for 2014 unchanged at 420,000 ounces of gold. The total material moved from its open pit mines continued well from the previous quarter with a small increase of 1% to 9,749 kilotonnnes (kt). A decrease in open pit ore production of 26% on the fourth quarter of 2013 to 2,325kt was due to a focus on waste stripping activities in line with the mine plan. The run of mine ore stockpile balance decreased by 216kt to 1,540kt at the end of the period. Record quarterly throughput at the process plant was 1,486kt, a 6% increase on the prior year period and a 6% increase on the previous quarter3, exceeding the nameplate annualised rate of 5mn tonnes for the fifth successive quarter with continued high levels of productivity and availability. The Stage 4 commissioning process will progressively lift overall plant throughput and hence gold production levels through the remainder of the year. Centamin said: "The primary challenge faced during the quarter was from poor mining fleet availability within the high-grade stoping areas of the underground mine. Whilst the operation delivered a record 206kt of ore, up 18% on Q4 2013, this limited ability to remotely mine the high-grade stopes reduced the average mined grade to below planned levels and thus restricted the contribution to overall production."These problems with equipment availability were rectified late in the quarter.OH