diff --git a/src/Generating/GridStructGen.cpp b/src/Generating/GridStructGen.cpp
index 3bbc89054..bfa6bccb1 100644
--- a/src/Generating/GridStructGen.cpp
+++ b/src/Generating/GridStructGen.cpp
@@ -22,6 +22,15 @@ cGridStructGen::cGridStructGen(
 	m_MaxStructureSizeZ(a_MaxStructureSizeZ),
 	m_MaxCacheSize(a_MaxCacheSize)
 {
+	size_t NumStructuresPerQuery = (size_t)((m_MaxStructureSizeX / m_GridSizeX + 1) * (m_MaxStructureSizeZ / m_GridSizeZ + 1));
+	if (NumStructuresPerQuery > m_MaxCacheSize)
+	{
+		m_MaxCacheSize = NumStructuresPerQuery * 4;
+		LOGINFO(
+			"cGridStructGen: The cache size is too small (%u), increasing the cache size to %u to avoid inefficiency.",
+			(unsigned)a_MaxCacheSize, (unsigned)m_MaxCacheSize
+		);
+	}
 }
 
 
diff --git a/src/Generating/MineShafts.cpp b/src/Generating/MineShafts.cpp
index 391e4c04f..81ae6481d 100644
--- a/src/Generating/MineShafts.cpp
+++ b/src/Generating/MineShafts.cpp
@@ -1283,7 +1283,7 @@ cStructGenMineShafts::cStructGenMineShafts(
 	int a_Seed, int a_GridSize, int a_MaxSystemSize,
 	int a_ChanceCorridor, int a_ChanceCrossing, int a_ChanceStaircase
 ) :
-	super(a_Seed, a_GridSize, a_GridSize, 120 + a_MaxSystemSize * 10, 120 + a_MaxSystemSize * 10, 100),
+	super(a_Seed, a_GridSize, a_GridSize, a_MaxSystemSize, a_MaxSystemSize, 100),
 	m_Noise(a_Seed),
 	m_GridSize(a_GridSize),
 	m_MaxSystemSize(a_MaxSystemSize),